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PIMCO ETF Trust

01/14/2026 | Press release | Distributed by Public on 01/14/2026 13:25

Prospectus by Investment Company (Form 497)

PIMCO ETF Trust

Prospectus

December 2, 2025 (as supplemented January 14, 2026)

	TICKER	EXCHANGE
PIMCO US Stocks PLUS Active Bond Exchange-Traded Fund	SPLS	Cboe

Neither the U.S. Securities and Exchange Commission nor the U.S. Commodity Futures Trading Commission has approved or disapproved these securities, or determined if this prospectus is truthfuI or compIete. Any representation to the contrary is a criminaI offense.

Table of Contents

	Page
Fund Summary	1
PIMCO US Stocks PLUS Active Bond Exchange-Traded Fund	1
Summary of Other Important Information Regarding Fund Shares	5
Summary Information About the Fund	7
Description of Principal Risks	7
Disclosure of Portfolio Holdings	21
Management of the Fund	22
Buying and Selling Shares	25
How Net Asset Value Is Determined	27
Fund Distributions	28
Tax Consequences	28
Characteristics and Risks of Securities and Investment Techniques	30
Financial Highlights	50
Appendix A - Description of Securities Ratings	A-1

PIMCO US Stocks PLUS Active Bond Exchange-Traded Fund

Investment Objective

The Fund seeks total return which exceeds that of its benchmark index consistent with prudent investment management.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees (fees paid directly from your investment):

N/A

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Management Fees	0.35%
Other Expenses(1)	0.05%
Acquired Fund Fees and Expenses(1)(2)	0.03%
Total Annual Fund Operating Expenses	0.43%
Fee Waiver and/or Expense Reimbursement(2)(3)	(0.25%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	0.18%

"Other Expenses" and "Acquired Fund Fees and Expenses" reflect estimated expenses for the Fund's first fiscal year.

Pacific Investment Management Company LLC ("PIMCO") has contractually agreed, through October 31, 2027, to waive its management fee, or reimburse the Fund, to the extent that organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustees' fees exceed 0.0049% of the Fund's average net assets (the "Expense Limit"). Under the Expense Limitation Agreement, which renews annually for a full year unless terminated by PIMCO upon at least 30 days' notice prior to the end of the contract term, PIMCO may recoup these waivers and reimbursements in future periods, not exceeding three years, provided that organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustees' fees, plus recoupment, do not exceed the Expense Limit (or the amount of the expense limit in place at the time the amount being recouped was originally waived if lower than the Expense Limit).

PIMCO has contractually agreed, through October 31, 2027, to reduce its management fee by 0.20% of the average daily net assets of the Fund. In any month in which the investment management agreement is in effect, PIMCO is entitled to reimbursement by the Fund of any portion of the management fee waived as set forth above (the "Fee Waiver Reimbursement Amount") during the previous thirty-six months from the time of the waiver, provided that such amount paid to PIMCO will not: 1) together with any recoupment of organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustee fees pursuant to the Expense Limitation Agreement, exceed the Expense Limit (calculated as a percentage of average daily net assets) (or the amount of the expense limit in place at the time the amount being recouped was originally waived if lower than the Expense Limit); 2) exceed the total Fee Waiver Reimbursement Amount; or 3) include any amounts previously reimbursed to PIMCO.

Example. The Example is intended to help you compare the cost of investing in the Fund with the costs of investing in other exchange-traded funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then hold or sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's

operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 Year	3 Years
$18	$113

Portfolio Turnover

The Fund pays transaction costs when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example tables, affect the Fund's performance. The Fund had not yet commenced operations as of the most recent fiscal year end. Thus, no portfolio turnover rate is provided for the Fund.

Principal Investment Strategies

The Fund seeks to provide investors with two different sources of exposure: (1) a portfolio of U.S.-listed equities, which is primarily designed to gain exposure to the 500 largest U.S.-listed companies, weighted by market capitalization (the "Equity Portfolio"), and (2) a portfolio of Fixed Income Instruments of varying maturities, which is primarily expected to consist of exposure to one or more PIMCO actively-managed fixed-income ETFs (the "Fixed Income Portfolio"). "Fixed Income Instruments" include bonds, debt securities and other similar instruments issued by various U.S. and non-U.S. public- or private-sector entities. The Fund will invest, under normal circumstances, at least 80% of its assets in a combination of the Equity Portfolio and Fixed Income Portfolio, which may be represented by underlying funds, options, futures contracts, or swap agreements.

The Fund generally intends to consider the federal income tax impact of the manner in which it seeks to obtain and dispose of investment exposures. The Fund's benchmark index is the S&P 500 Index.

Equity Portfolio

With respect to the Equity Portfolio, the Fund will, under normal circumstances, invest directly in U.S.-listed equity securities and/or indirectly in instruments (such as investments in one or more other funds, which may include third-party managed exchange-traded funds ("ETFs"), and/or derivative instruments) with the intent of, in the aggregate, providing gross returns approximately resembling those of the 500 largest U.S.-listed companies, weighted by market capitalization. The Fund expects to primarily obtain such exposure through indirect investments, such as through investments in one or more third-party managed funds.

Fixed Income Portfolio

With respect to the Fixed Income Portfolio, the Fund will, under normal circumstances, invest indirectly through investments in, or derivatives on, one or more actively-managed fixed-income funds of PIMCO ETF Trust ("PIMCO Active Fixed-Income ETFs"). When determining the target PIMCO Active Fixed-Income ETF allocation, PIMCO intends to use risk-based analysis and consider related

PIMCO ETF Trust | Prospectus 1

PIMCO US Stocks PLUS Active Bond Exchange-Traded Fund

funding costs, which may be an implicit cost within derivatives instruments. The risk-based framework is developed and maintained by PIMCO, and is subject to change over time without notice in PIMCO's discretion. The notional fixed income exposure of the Fund is expected to be at or above the Fund's net assets. To the extent the Fund seeks exposure to PIMCO Active Fixed-Income ETFs, PIMCO expects to select such ETFs without considering or canvassing the universe of available unaffiliated funds. Under non-normal circumstances, the Fixed Income Portfolio may be invested directly in Fixed Income Instruments.

The Fund expects to primarily obtain such exposure through derivatives (such as entering into total return swaps, purchasing call options, and/or selling put options) on PIMCO Active Fixed-Income ETFs. Although the Fund may gain exposure to multiple PIMCO Active Fixed-Income ETFs, the Fund generally expects to primarily gain exposure to the PIMCO Enhanced Short Maturity Active Exchange-Traded Fund, the PIMCO Enhanced Low Duration Active Exchange-Traded Fund, and the PIMCO Ultra Short Government Active Exchange-Traded Fund. You may view the PIMCO Enhanced Short Maturity Active Exchange-Traded Fund's, the PIMCO Enhanced Low Duration Active Exchange-Traded Fund's, and the PIMCO Ultra Short Government Active Exchange-Traded Fund's prospectus, Statement of Additional Information, Form N-CSR and annual and semi-annual reports at www.pimcoetfs.com.

The Fund may also invest without limit in securities issued by the U.S. Government, its agencies or government-sponsored entities, derivatives and repurchase agreements related thereto (such as U.S. Treasury futures and interest rate swaps), and/or interest rate futures. The allocation to such instruments will also be evaluated within the risk-based framework alongside the exposure to PIMCO Active Fixed-Income ETFs. The Fund may also engage in financing transactions, such as reverse repurchase agreements and/or total return swaps.

Subject to the risk-based framework described above, the Fund's Fixed Income Portfolio may be of any duration. Duration is a measure used to determine the sensitivity of a security's price to changes in interest rates. The longer a security's duration, the more sensitive it will be to changes in interest rates. The Fund's Fixed Income Portfolio may be exposed to high yield securities ("junk bonds") of any rating or unrated securities. The Fund's Fixed Income Portfolio may invest in securities denominated in foreign currencies, securities of foreign issuers, and securities and instruments economically tied to emerging market countries.

The Fund may invest, without limitation, in derivative instruments, such as options, futures contracts or swap agreements. The Fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis and may engage in short sales. The Fund is non-diversified, which means that it may invest its assets in a smaller number of issuers than a diversified fund.

The total return sought by the Fund may include both capital appreciation arising from increases in the market value of the Fund's holdings and income earned on the Fund's investments, if any. Investors

should be aware that the investments made by the Fund and the results achieved by the Fund at any given time, including for the same or similar investments, are not expected to be the same as those made by other funds for which PIMCO acts as investment adviser, including funds with names, investment objectives and policies, and/or portfolio management teams, similar to the Fund.

Principal Risks

It is possible to lose money on an investment in the Fund.Under certain conditions, generally in a market where the value of both the Fund's Equity Portfolio and Fixed Income Portfolio are declining or in periods of heightened market volatility, the Fund may experience greater losses or lesser gains than would be the case if it invested directly in Fixed Income Instruments and/or equities instead of derivatives.

The principal risks of investing in the Fund include risks from direct investments and/or indirect exposure through investment in, or taking derivative positions on, PIMCO Active Fixed-Income ETFs and third-party managed funds. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return, are:

New Fund Risk: the risk that a new fund's performance may not represent how the fund is expected to or may perform in the long term. In addition, new funds have limited operating histories for investors to evaluate and new funds may not attract sufficient assets to achieve investment and trading efficiencies

Small Fund Risk: the risk that a smaller fund may not achieve investment or trading efficiencies or may be limited in ability to participate in certain investment opportunities due to its size. Additionally, a smaller fund may be more adversely affected by large purchases or redemptions by investors

Acquired Fund Risk: the risk that the Fund's performance is closely related to the risks associated with the securities and other investments held by the PIMCO Active Fixed-Income ETFs and third-party managed funds in which the Fund invests or enters into derivatives on ("underlying funds"), and that the ability of the Fund to achieve its investment objective will depend upon the ability of the underlying funds to achieve their investment objectives. Investments in, or derivatives exposure to, underlying funds that are exchange-traded funds are also subject to market risk, tracking error, the potential for trading at a discount or premium to their net asset value, bid/ask spread risk as well as the risks of the underlying securities they hold. In addition, the Fund's performance will be reduced by the Fund's proportionate amount of the expenses of any underlying funds in which it invests or enters into derivatives on

Market Trading Risk: the risk that an active secondary trading market for Fund shares does not continue once developed, that the Fund may not continue to meet a listing exchange's trading or listing requirements, that trading in Fund shares may be halted or become less liquid, or that Fund shares trade at prices other than the Fund's net asset value and are subject to trading costs. These risks may be exacerbated if the creation/redemption process becomes less effective, particularly during times of market stress or volatility

2 Prospectus| PIMCO ETF Trust

Prospectus

Interest Rate Risk: the risk that fixed income securities and dividend-paying equity securities will fluctuate in value due to changes in interest rates; a fund with a longer average portfolio duration will be more sensitive to changes in interest rates than a fund with a shorter average portfolio duration. Factors such as government policy, inflation, the economy, and market for bonds can impact interest rates and yields

Call Risk: the risk that an issuer may exercise its right to redeem a fixed income security earlier than expected (a call). Issuers may call outstanding securities prior to their maturity for a number of reasons including declining interest rates, changes in credit spreads and improvements in the issuer's credit quality. If an issuer calls a security that the Fund has invested in, the Fund may not recoup the full amount of its initial investment or may not realize the full anticipated earnings from the investment and may be forced to reinvest in lower-yielding securities, securities with greater credit risks or securities with other, less favorable features

Credit Risk: the risk that the Fund could experience losses if the issuer or guarantor of a fixed income security, or the counterparty to a derivative contract, or the issuer or guarantor of collateral, is unable or unwilling, or is perceived (whether by market participants, rating agencies, pricing services or otherwise) as unable or unwilling, to meet its financial obligations

High Yield Risk: the risk that high yield securities and unrated securities of similar credit quality (commonly known as "junk bonds") are subject to greater levels of market, credit, call and liquidity risks. High yield securities are considered primarily speculative by rating agencies with respect to the issuer's continuing ability to make principal and interest payments, and their values may be more volatile than higher-rated securities of similar maturity

Market Risk: the risk that the value of securities owned by the Fund may fluctuate, sometimes rapidly or unpredictably, due to a variety of factors affecting securities markets generally or particular industries or sectors

Issuer Risk: the risk that the value of a security may decline for reasons related to the issuer, such as management performance, changes in financial condition or credit rating, financial leverage, reputation or reduced demand for the issuer's goods or services

Liquidity Risk: the risk that a particular investment may be difficult to purchase or sell and that the Fund may be unable to sell investments at an advantageous time or price or achieve its desired level of exposure to a certain sector. Liquidity risk may result from the lack of an active market, reduced number and capacity of traditional market participants to make a market in fixed income securities, and may be magnified in a rising interest rate environment or other circumstances where investor redemptions from fixed income funds may be higher than normal, causing increased supply in the market due to selling activity. The liquidity of the Fund's shares may be constrained by the liquidity of the Fund's portfolio holdings

Derivatives Risk: the risk of investing in derivative instruments (such as forwards, futures, options, swaps and structured securities) and other

similar investments, including leverage, liquidity, interest rate, market, counterparty (including credit), operational, legal and management risks, and valuation complexity. Changes in the value of a derivative or other similar investment may not correlate perfectly with, and may be more sensitive to market events than, the underlying asset, rate or index, and the Fund could lose more than the initial amount invested. Changes in the value of a derivative or other similar instrument may also create margin delivery or settlement payment obligations for the Fund. The Fund's use of derivatives or other similar investments may result in losses to the Fund, a reduction in the Fund's returns and/or increased volatility. Non-centrally-cleared over-the-counter ("OTC") derivatives or other similar investments are also subject to the risk that a counterparty to the transaction will not fulfill its contractual obligations to the other party, as many of the protections afforded to centrally-cleared derivative transactions might not be available for non-centrally cleared OTC derivatives or other similar investments. The primary credit risk on derivatives or other similar investments that are exchange-traded or traded through a central clearing counterparty resides with the Fund's clearing broker or the clearinghouse. Changes in regulation relating to a registered fund's use of derivatives and related instruments could potentially limit or impact the Fund's ability to invest in derivatives, limit the Fund's ability to employ certain strategies that use derivatives or other similar investments and/or adversely affect the value of derivatives or other similar investments and the Fund's performance When the Fund obtains indirect exposure to another fund through derivatives, the investing fund will bear expenses embedded within the derivative, which generally would be expected to include the fees and expenses of the underlying fund as well as other expenses, such as those imposed by a counterparty or clearing agency. These accumulated costs and expenses will detract from the gross performance of the derivative and a fund's economic returns for such an investment will be net of these fees and expenses. Unlike direct investment in shares of the underlying funds, these expenses will not be considered acquired fund fees and expenses and therefore will not be included in the Fund's Annual Fund Operating Expenses table. PIMCO will not waive any expenses of an underlying PIMCO fund that are embedded within the derivative from the investing fund's (such as the Fund's) management fees. As a result, PIMCO may receive management fee revenue from the increase in assets in the underlying PIMCO fund associated with any hedging activity by the counterparty to the investing fund's (such as the Fund's) derivatives, as it is common for such counterparties to hedge their derivatives exposure by investing directly in the underlying reference asset, which fees are in addition to the Fund's management fees.

Issuer Non-Diversification Risk: the risk of focusing investments on a small number of issuers, including being more susceptible to risks associated with a single economic, political or regulatory occurrence than a more diversified portfolio might be. Funds that are "non-diversified" may invest a greater percentage of their assets in the securities of a single issuer (such as bonds issued by a particular state) than funds that are "diversified"

December 2, 2025 (as supplemented January 14, 2026) | Prospectus 3

PIMCO US Stocks PLUS Active Bond Exchange-Traded Fund

Exchange-Traded Fund Risk: the risk that an exchange-traded fund may not achieve its investment objective, among other reasons, because of regulatory restrictions, including, for example, exchange rules, market prices of shares of an exchange-traded fund may fluctuate rapidly and materially, or shares of an exchange-traded fund may trade significantly above or below net asset value, any of which may cause losses to the Fund invested in the exchange-traded fund

Equity Risk: the risk that the value of equity or equity-related securities, such as common stocks and preferred securities, may decline due to general market conditions which are not specifically related to a particular company or to factors affecting a particular industry or industries. Equity or equity-related securities generally have greater price volatility than fixed income securities. In addition, preferred securities may be subject to greater credit risk or other risks, such as risks related to deferred and omitted distributions, limited voting rights, liquidity, interest rates, regulatory changes and special redemption rights

Mortgage-Related and Other Asset-Backed Securities Risk: the risks of investing in mortgage-related and other asset-backed securities, including interest rate risk, extension risk, prepayment risk and credit risk. The Fund may invest in any tranche of mortgage-related and other asset-backed securities, including junior and/or equity tranches (to the extent consistent with other of the Fund's guidelines), which generally carry higher levels of the foregoing risks

Foreign (Non-U.S.) Investment Risk: the risk that investing in foreign (non-U.S.) securities may result in the Fund experiencing more rapid and extreme changes in value than a fund that invests exclusively in securities of U.S. companies, due to smaller or less developed markets, differing financial reporting, accounting, corporate governance and auditing standards, increased risk of delayed settlement of portfolio transactions or loss of certificates of portfolio securities, and the risk of unfavorable U.S. or foreign government actions, including nationalization, expropriation or confiscatory taxation, currency blockage, political changes, diplomatic developments, trade restrictions (including tariffs) or the imposition of sanctions and other similar measures. Foreign securities may also be less liquid and more difficult to value than securities of U.S. issuers

Emerging Markets Risk: the risk of investing in emerging market securities, primarily increased foreign (non-U.S.) investment risk

Sovereign Debt Risk: the risk that investments in fixed income instruments issued by sovereign entities may decline in value as a result of default or other adverse credit events resulting from an issuer's inability or unwillingness to make principal or interest payments in a timely fashion

Currency Risk: the risk that foreign (non-U.S.) currencies may fluctuate in value relative to the U.S. dollar, which can affect the value of the Fund's investments in foreign (non-U.S.) currencies or in securities that trade in, and receive revenues in, or in derivatives that provide exposure to, foreign (non-U.S.) currencies

Leveraging Risk: the risk that certain transactions of the Fund, such as reverse repurchase agreements, loans of portfolio securities, the use of when-issued, delayed delivery or forward commitment transactions, or derivative instruments and that the Fund's portfolio providing fixed income exposure that is in addition to the targeted equity returns of the Fund, will give rise to leverage, magnifying gains and losses and causing the Fund to be more volatile than if it had not been leveraged. This means that leverage entails a heightened risk of loss. The use of leverage may also increase the Fund's sensitivity to interest rate risks

Management Risk: the risk that the investment techniques and risk analyses applied by PIMCO will not produce the desired results and that actual or potential conflicts of interest, legislative, regulatory, or tax restrictions, policies or developments may affect the investment techniques available to PIMCO and the individual portfolio managers in connection with managing the Fund and may cause PIMCO to restrict or prohibit participation in certain investments. There is no guarantee that the investment objective of the Fund will be achieved

Model Risk: the risk that the Fund's investment models used in making investment allocation decisions may not adequately take into account certain factors, or may contain design flaws or faulty assumptions, and may rely on incomplete or inaccurate data inputs, any of which may result in a decline in the value of an investment in the Fund. The performance of the investment models may be impacted by software or other technology malfunctions, human error, programming inaccuracies, power loss, and other events or circumstances, which may be difficult to detect and may be beyond the control of the Fund

Futures Contract Risk: the risk that, while the value of a futures contract tends to correlate with the value of the underlying asset that it represents, differences between the futures market and the market for the underlying asset may result in an imperfect correlation. Futures contracts may involve risks different from, and possibly greater than, the risks associated with investing directly in the underlying assets. The purchase or sale of a futures contract may result in losses in excess of the amount invested in the futures contract. In addition, futures contracts may expose the Fund to leverage risk, liquidity risk, market volatility, and margin requirements

Short Exposure Risk: the risk of entering into short sales or other short positions, including the potential loss of more money than the actual cost of the investment, and the risk that the third party to the short sale or other short position will not fulfill its contractual obligations, causing a loss to the Fund

Collateralized Loan Obligations Risk: the risk that investing in collateralized loan obligations ("CLOs") and other similarly structured investments exposes the Fund to heightened credit risk, interest rate risk, liquidity risk, market risk and prepayment and extension risk, as well as the risk of default on the underlying asset. In addition, investments in CLOs carry additional risks, including, but not limited to: (i) the possibility that distributions from collateral securities will not be adequate to make interest or other payments; (ii) the quality of the collateral may decline in value or default; (iii) risks related to the capability of the servicer of the securitized assets; (iv) the risk that the

4 Prospectus| PIMCO ETF Trust

Prospectus

Fund may invest in tranches of CLOs that are subordinate to other tranches; (v) the structure and complexity of the transaction and the legal documents may not be fully understood at the time of investment and could lead to disputes with the issuer or among investors regarding the characterization of proceeds or unexpected investment results; and (vi) the CLO's manager may perform poorly

Tax-Efficient Investing Risk: the risk that investment strategies intended to manage the tax consequences of the Fund's investments may not succeed, and that such strategies may reduce investment returns or result in investment losses. Further, the Fund may realize taxable gains in order to satisfy cash redemptions or incur other tax consequences of transactions that PIMCO otherwise believes are beneficial to the Fund

Turnover Risk: the risk that high levels of portfolio turnover may increase transaction costs and taxes and may lower investment performance

Tracking Error Risk: the risk that the Equity Portfolio, to the extent it seeks to track the investment results of a group of issuers' equity securities, may not closely track the performance of such a group for a number of reasons. For example, the Fund incurs operating expenses, which are not applicable to the group of issuers' equity securities, and the costs of buying and selling securities, especially when rebalancing the Equity Portfolio to reflect changes in the composition of the group of issuers' equity securities. Performance of the Equity Portfolio and the group of issuers' equity securities may vary due to asset valuation differences and differences between the Fund's portfolio and the group of issuers' equity securities due to legal restrictions, cost or liquidity restraints. The risk that performance of the Fund and the group of issuers' equity securities may be heightened during periods of increased market volatility or other unusual market conditions. In addition, to the extent an underlying fund uses a representative sampling approach, such underlying fund's returns may be less correlated to the return of the group of issuers' equity securities than if the underlying fund held all of the securities in the group of issuers' equity securities

Indexing Risk: the risk that the Equity Portfolio, to the extent that it seeks to track the investment results of a group of issuers' equity securities, is negatively affected by general declines in the asset classes represented by the group of issuers' equity securities

Please see "Description of Principal Risks" in the Fund's prospectus for a more detailed description of the risks of investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Investment Adviser/Portfolio Managers

PIMCO serves as the investment adviser for the Fund. The Fund's portfolio is jointly and primarily managed by Jerome Schneider, Joshua Spitz and Tanuj Dora. Mr. Schneider is a Managing Director of PIMCO. Mr. Spitz is an Executive Vice President of PIMCO. Mr. Dora is a Senior Vice President of PIMCO. Messrs Schneider, Spitz and Dora have managed the Fund since its inception.

Performance Information

The Fund does not have a full calendar year of performance. Thus, no bar chart or Average Annual Total Returns table is included for the Fund. Once the Fund commences operations, performance for the Fund will be updated daily and quarterly and may be obtained as follows: daily and quarterly updates on the net asset value and performance page at https://www.pimco.com/us/en/product-finder?filters=products=etf.

Purchase and Sale of Fund Shares

The Fund is an exchange-traded fund ("ETF"). Individual Fund shares may only be purchased and sold on a national securities exchange through a broker-dealer and may not be purchased or redeemed directly with the Fund.

The price of Fund shares is based on market price, and because ETF shares trade at market prices rather than net asset value ("NAV"), shares may trade at a price greater than NAV (a premium) or less than NAV (a discount). An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund ("bid") and the lowest price a seller is willing to accept for shares ("ask") when buying or selling shares in the secondary market (the "bid-ask spread"). Recent information, including information about the Fund's NAV, market price, premiums and discounts, and bid-ask spreads, is included on the Fund's website at https://www.pimco.com/en-us/investments/etf.

Tax Information

The Fund's distributions are generally taxable to you as ordinary income, capital gains, or a combination of the two, unless you are investing through a tax-deferred arrangement, such as a 401(k) plan or an individual retirement account, in which case distributions may be taxable upon withdrawal.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase Fund shares through a broker-dealer or other financial intermediary, PIMCO or other related companies may pay the intermediary for the sale of Fund shares or related services. These payments may create a conflict of interest by influencing the

December 2, 2025 (as supplemented January 14, 2026) | Prospectus 5

PIMCO US Stocks PLUS Active Bond Exchange-Traded Fund

broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary's website for more information.

6 Prospectus| PIMCO ETF Trust

Prospectus

Summary Information About the Fund

This prospectus describes the PIMCO US Stocks PLUS Active Bond Exchange-Traded Fund (the "Fund") offered by PIMCO ETF Trust (the "Trust"). The Fund provides access to the professional investment advisory services offered by PIMCO.

ETFs are funds that trade like other publicly-traded securities and may be designed to track an index or to be actively managed. Unlike conventional ETFs, the Fund is not an index fund. The Fund is actively managed and does not seek to replicate the performance of a specified index. Unlike shares of a mutual fund, which can be bought from and redeemed by the issuing fund by all shareholders at a price based on NAV, shares of the Fund may be directly purchased from and redeemed by the Fund at NAV solely by a member or participant of a clearing agency registered with the Securities and Exchange Commission, which has a written agreement with the Fund's Distributor that allows such member or participant to place orders for the purchase and redemption of Creation Units (as defined below) ("Authorized Participant"). Also unlike shares of a mutual fund, shares of the Fund are listed on a national securities exchange and trade in the secondary market at market prices that change throughout the day.

Once operational, shares of the Fund are listed and traded at market prices on Cboe BZX Exchange, Inc. ("Cboe") and other secondary markets. The market price for the Fund's shares may be different from the Fund's NAV. The Fund issues and redeems shares at NAV only in aggregations of a specified number of shares ("Creation Units"). Only Authorized Participants may purchase or redeem Creation Units directly with the Fund at NAV. These transactions are in exchange for securities and/or cash. Except when aggregated in Creation Units, shares of the Fund are not redeemable securities. Shareholders who are not Authorized Participants may not purchase or redeem shares directly from the Fund.

If the Fund were to effect redemptions with an Authorized Participant primarily for cash, the Fund may be required to sell portfolio securities in order to obtain the cash needed to distribute redemption proceeds. The sale of portfolio securities could cause the Fund to recognize gains that it might not otherwise have recognized if redemptions were effected in-kind, or to recognize such gain sooner than would otherwise be required. Such gains will generally be distributed to shareholders to avoid taxation at the Fund level and to ensure compliance with other special tax rules that apply to the Fund. Moreover, the sale of portfolio securities will generally subject the Fund to transaction costs, which may be partially or totally offset by the variable transaction fee charged by the Fund to redeeming Authorized Participants.

An investment in the Fund alone should not constitute an entire investment program. This prospectus explains what you should know about the Fund before you invest. Please read it carefully. Certain affiliates of the Fund and PIMCO may purchase and resell Fund shares pursuant to this prospectus.

On each business day, before commencement of trading on Cboe, the Fund will disclose on www.pimcoetfs.com the identities and quantities of the Fund's portfolio holdings that will form the basis for the Fund's calculation of NAV at the end of the business day. The Fund fact sheet provides additional information regarding the Fund and may be requested by calling 1.888.400.4ETF (1.888.400.4383).

Description of Principal Risks

The value of your investment in the Fund changes with the market price of the Fund's shares determined in the secondary market. Market price may be determined, in part, by the values of the Fund's investments. Many factors can affect those values. The factors that are most likely to have a material effect on the Fund's portfolio as a whole are called "principal risks." The principal risks of the Fund are identified in the Fund Summary and are described in this section. The Fund may be subject to additional risks other than those identified and described below because the types of investments made by the Fund can change over time. Securities and investment techniques mentioned in this summary that appear in bold type are described in greater detail under "Characteristics and Risks of Securities and Investment Techniques." That section and "Investment Objectives and Policies" in the Statement of Additional Information ("SAI") also include more information about the Fund, its investments and the related risks. There is no guarantee that the Fund will be able to achieve its investment objective. It is possible to lose money by investing in the Fund.

As the Fund may invest in shares of PIMCO Active Fixed-Income ETFs and third-party managed funds, the risks of investing in a Fund may be closely related to the risks associated with PIMCO Active Fixed-Income ETFs and third-party managed funds and their investments. However, as the Fund may also invest its assets directly in stocks or bonds of other issuers and in other instruments, such as forwards, options, futures contracts or swap agreements, the Fund may be directly exposed to certain risks described below. As such, unless stated otherwise, any reference in this section only to a "Fund" includes the Fund, together with the PIMCO Active Fixed-Income ETFs and third-party managed funds in which the Fund invests and/or enters into derivatives on.

New Fund Risk

A new Fund's performance may not represent how the Fund is expected to or may perform in the long term if and when it becomes larger and has fully implemented its investment strategies. Investment positions may have a disproportionate impact (negative or positive) on performance in new Funds. New Funds may also require a period of time before they are fully invested in securities that meet their investment objectives and policies and achieve a representative portfolio composition. Fund performance may be lower or higher during this "ramp-up" period, and may also be more volatile, than would be the case after the Fund is fully invested. Similarly, a new Fund's investment strategy may require a longer period of time to show returns that are representative of the strategy. New Funds have limited performance histories for investors to evaluate and new Funds may not

December 2, 2025 (as supplemented January 14, 2026) | Prospectus 7

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attract sufficient assets to achieve investment and trading efficiencies. If a new Fund were to fail to successfully implement its investment strategies or achieve its investment objective, performance may be negatively impacted, and any resulting liquidation could create negative transaction costs for the Fund and tax consequences for investors.

Small Fund Risk

A smaller fund may not grow to or maintain an economically viable size to achieve investment or trading efficiencies or may be limited in ability to participate in certain investment opportunities due to its size, which may negatively impact performance and/or force the fund to liquidate. Additionally, a smaller fund may be more adversely affected by large purchases or redemptions by investors, which can occur at any time and may impact the fund in the same manner as a high volume of purchases or redemptions.

Acquired Fund Risk

Because the Fund may invest its assets in or take derivative positions on PIMCO Active Fixed-Income ETFs and third-party managed funds, the risks associated with investing in the Fund may be closely related to the risks associated with the securities and other investments held by the PIMCO Active Fixed-Income ETFs and third-party managed funds. The ability of the Fund to achieve its investment objective may depend upon the ability of the PIMCO Active Fixed-Income ETFs and third-party managed funds to achieve their respective investment objectives. Investments in or derivative positions on PIMCO Active Fixed-Income ETFs and third-party managed funds that are exchange-traded funds are also subject to market risk, tracking error, the potential for trading at a discount or premium to their net asset value, bid/ask spread risk as well as the risks of the underlying securities they hold. In addition, the Fund's performance will be reduced by the proportionate amount of the expenses of any PIMCO Active Fixed-Income ETFs and third-party managed funds in which the Fund invests or enters into derivative positions on. In addition, shareholders of the Fund will bear the Fund's direct fees and expenses. There can be no assurance that the investment objective of any PIMCO Active Fixed-Income ETFs or third-party managed funds will be achieved.

The Fund's net asset value ("NAV") will fluctuate in response to changes in the NAVs and/or market prices of the PIMCO Active Fixed-Income ETFs and third-party managed funds in which it invests. The extent to which the investment performance and risks associated with the Fund correlates to those of a particular PIMCO Active Fixed-Income ETFs or third-party managed fund will depend upon the extent to which the Fund's assets are allocated from time to time for investment in the PIMCO Active Fixed-Income ETFs or third-party managed funds, which may vary.

As discussed under "Description of Principal Risks-Market Risk," because the NAV of the Fund is related to the NAVs and/or market prices of the PIMCO Active Fixed-Income ETFs and third-party managed funds in which it invests, inaccuracies, delays or other disruptions in the calculation of a PIMCO Active Fixed-Income ETF's or third-party managed fund's NAV and/or market prices may adversely impact the Fund.

Market Trading Risk

The Fund is subject to secondary market trading risks. Shares of the Fund are listed for trading on an exchange, however, there can be no guarantee that an active trading market for such shares will develop or continue. Shares of the Fund may be listed or traded on U.S. and foreign (non-U.S.) exchanges other than the Fund's primary U.S. listing exchange. There can be no guarantee that the Fund's shares will continue trading on any exchange or in any market or that the Fund's shares will continue to meet the listing or trading requirements of any exchange or market. The Fund's shares may experience higher trading volumes on one exchange as compared to another and investors are subject to the execution and settlement risks of the market where their broker directs trades.

Secondary market trading in the Fund's shares may be halted by an exchange because of market conditions. Pursuant to exchange or market rules, trading in the Fund's shares on an exchange or in any market may be subject to trading halts caused by extraordinary market volatility. If secondary market trading is halted or an exchange closes earlier than anticipated, it may be impossible to purchase or sell Fund shares. Additionally, the secondary market for trading an exchange-traded fund's shares may become less liquid in stressed market conditions and when the underlying holdings of the exchange-traded fund are difficult to buy or sell. There can be no guarantee that the Fund's exchange listing or ability to trade its shares will continue or remain unchanged. In the event the Fund ceases to be listed on an exchange, the Fund may cease operating as an "exchange-traded" fund and operate as a mutual fund, provided that shareholders are given advance notice.

Buying or selling the Fund's shares on an exchange may require the payment of brokerage commissions. The commission is frequently a fixed amount and may be a significant cost for investors seeking to buy or sell small amounts of shares. In addition, an investor who buys or sells may also incur the cost of the spread (the difference between the bid price and the ask price). The spread varies over time for shares of the Fund based on their trading volume and market liquidity and is generally less if the Fund has more trading volume and market liquidity and more if the Fund has less trading volume and market liquidity. Due to the costs inherent in buying or selling the Fund's shares, frequent trading may detract significantly from investment returns. Investment in the Fund's shares may not be advisable for investors who expect to engage in frequent trading.

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Prospectus

Shares of the Fund may trade on an exchange at prices at, above or below their most recent NAV, which could result in an investor buying shares of the Fund at a higher price than the Fund's NAV or selling shares of the Fund at a lower price than the Fund's NAV. The market prices of Fund shares will fluctuate, sometimes rapidly and materially, in response to changes in the Fund's NAV, the value of Fund holdings and supply and demand for Fund shares. Although the creation/redemption feature of the Fund generally makes it more likely that Fund shares will trade close to NAV, market volatility, lack of an active trading market for Fund shares, disruptions at market participants (such as Authorized Participants or market makers) and any disruptions in the ordinary functioning of the creation/redemption process may result in Fund shares trading significantly above (at a "premium") or below (at a "discount") NAV. Additionally, to the extent the Fund holds securities traded in markets that close at a different time from the Fund's listing exchange, liquidity in such securities may be reduced after the applicable closing times, and during the time when the Fund's listing exchange is open but after the applicable market closing, fixing or settlement times, bid/ask spreads and the resulting premium or discount to the Fund's shares' NAV may widen. Selling shares may be difficult or may result in significant losses if transactions in Fund shares occur under these and other circumstances. Neither PIMCO nor the Trust can predict whether Fund shares will trade above, below or at NAV. The Fund's investment results are based on the Fund's daily NAV. Investors transacting in Fund shares in the secondary market, where market prices may differ from NAV, may experience investment results that differ from results based on the Fund's daily NAV. There are various methods by which investors can purchase and sell shares and various orders that may be placed. Investors should consult their financial intermediary before purchasing or selling shares of the Funds.

The Fund has a limited number of intermediaries that act as Authorized Participants, and none of these Authorized Participants are or will be obligated to engage in creation or redemption transactions. To the extent that these intermediaries exit the business or are unable to or choose not to proceed with creation and/or redemption orders with respect to the Fund and no other Authorized Participant is able and willing to create or redeem, shares may trade at a discount to NAV and possibly face trading halts and/ or delisting. Additionally, while Fund shares are listed for trading on an exchange, there can be no assurance that active trading markets for Fund shares will be maintained by market makers or Authorized Participants.

Decisions by market makers or Authorized Participants to reduce their role or "step away" from these activities in times of market stress or volatility may inhibit the effectiveness of the creation/redemption process in maintaining the relationship between the underlying value of the Fund's holdings and the Fund's NAV. Such reduced effectiveness could result in the Fund's shares trading at a discount to its NAV and also in greater than normal intraday bid/ask spreads for the Fund's shares.

Interest Rate Risk

Interest rate risk is the risk that fixed income securitiesand other instruments in the Fund's portfolio will fluctuate in value due to changes, or the anticipation of changes, in interest rates. Factors including central bank monetary policy, rising inflation rates, and changes in general economic conditions may cause interest rates to rise, which could cause the value of the Fund's investments to decline. For example, as nominal interest rates rise, the value of certain securities held by the Fund is likely to decrease. A nominal interest rate can be described as the sum of a real interest rate and an expected inflation rate. Interest rate changes can be sudden and unpredictable, and the Fund may experience losses as a result of movements in interest rates. The Fund may not be able to hedge against changes in interest rates or may choose not to do so for cost or other reasons. In addition, any hedges may not work as intended.

Fixed income securitieswith longer durations tend to be more sensitive to changes in interest rates, usually making them more volatile than securities with shorter durations. The values of equity and other non-fixed income securities may also decline due to fluctuations in interest rates. Inflation-indexed bonds, including Treasury Inflation-Protected Securities ("TIPS"), decline in value when real interest rates rise. In certain interest rate environments, such as when real interest rates are rising faster than nominal interest rates, inflation-indexed bondsmay experience greater losses than other fixed income securitieswith similar durations.

Dividend-paying equity securities, particularly those whose market price is closely related to their yield, may be more sensitive to changes in interest rates. During periods of rising interest rates, the values of such securities may decline and may result in losses to the Fund.

Variable and floating rate securitiesgenerally are less sensitive to interest rate changes but may decline in value if their interest rates do not rise as much, or as quickly, as interest rates in general. Conversely, floating rate securities will not generally increase in value if interest rates decline. Inverse floating rate securities may decrease in value due to changes in interest rates. Inverse floating rate securities may also exhibit greater price volatility than a fixed rate obligation with similar credit quality. When the Fund holds variable or floating rate securities, a decrease (or, in the case of inverse floating rate securities, an increase) in market interest rates will adversely affect the income received from such securities and the NAV of the Fund's shares.

A wide variety of factors can cause interest rates or yields of U.S. Treasury securities (or yields of other types of bonds) to rise, including but not limited to central bank monetary policies, changing inflation or real growth rates, general economic conditions, increasing bond issuances or reduced market demand for low yielding investments. Risks associated with changes in interest rates are heightened under certain market conditions, such as during times when the U.S. Federal Reserve (the "Federal Reserve") raises interest rates or when such rates remain elevated following a period of historically low levels. Additionally, the U.S. and other governments have increased, and are likely to continue increasing, their debt issuances, which may also

December 2, 2025 (as supplemented January 14, 2026) | Prospectus 9

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heighten these risks. There is the risk that the income generated by investments may not keep pace with inflation. Actions by governments and central banking authorities can result in increases or decreases in interest rates. Periods of higher inflation could cause such authorities to raise interest rates, which may adversely affect the Fund and its investments. In addition, changes in monetary policy may exacerbate the risks associated with changing interest rates. Further, in market environments where interest rates are rising, issuers may be less willing or able to make principal and interest payments on fixed income investments when due.

Rising interest rates may result in periods of volatility and a decline in value of the Fund's fixed income investments. Further, while U.S. bond markets have steadily grown over the past three decades, dealer "market making" ability has remained relatively stagnant. As a result, dealer inventories of certain types of bonds and similar instruments, which provide a core indication of the ability of financial intermediaries to "make markets," are at or near historic lows in relation to market size. Because market makers provide stability to a market through their intermediary services, the significant reduction in dealer inventories could potentially lead to decreased liquidity and increased volatility in the fixed income markets. Such issues may be exacerbated during periods of economic uncertainty. All of these factors, collectively and/or individually, could cause the Fund to lose value.

During periods of very low or negative interest rates, the Fund may be unable to maintain positive returns. Certain European countries have previously experienced negative interest rates on certain fixed income instruments. Very low or negative interest rates may magnify interest rate risk. Changing interest rates, including rates that fall below zero, may have unpredictable effects on markets, may result in heightened market volatility and may detract from the Fund's performance to the extent the Fund is exposed to such interest rates.

Measures such as average durationmay not accurately reflect the true interest rate sensitivity of the Fund. This is especially the case if the Fund consists of securities with widely varying durations. Therefore, if the Fund has an average durationthat suggests a certain level of interest rate risk, a Fund may in fact be subject to greater interest rate risk than the average would suggest. This risk is greater to the extent the Fund uses leverage or derivativesin connection with the management of the Fund.

Convexity is an additional measure used to understand a security's or the Fund's interest rate sensitivity. Convexity measures the rate of change of durationin response to changes in interest rates. With respect to a security's price, a larger convexity (positive or negative) may imply more dramatic price changes in response to changing interest rates. Convexity may be positive or negative. Negative convexity implies that interest rate increases result in increased duration, and vice versa, meaning increased sensitivity in prices in response to changes in interest rates. Thus, securities with negative convexity, which may include bonds with traditional call features and certain mortgage-backed securities, may experience greater losses in periods of rising interest rates. Accordingly, if the Fund holds such securities, the Fund may be subject to a greater risk of losses in periods of rising interest rates.

Call Risk

Call risk refers to the possibility that an issuer may exercise its right to redeem a fixed income securityearlier than expected (a call). Issuers may call outstanding securities prior to their maturity for a number of reasons (e.g.,declining interest rates, changes in credit spreads and improvements in the issuer's credit quality). If an issuer calls a security in which the Fund has invested, the Fund may not recoup the full amount of its initial investment or may not realize the full anticipated earnings from the investment and may be forced to reinvest in lower-yielding securities, securities with greater credit risks or securities with other, less favorable features.

Credit Risk

The Fund could experience losses if the issuer or guarantor of a fixed income security (including a security purchased with securities lending collateral), the counterparty to a derivativescontract or a repurchase agreement, a borrower of portfolio securities, or the issuer or guarantor of collateral, is unable or unwilling, or is perceived (whether by market participants, rating agencies, pricing services or otherwise) as unable or unwilling, to make timely principal and/or interest payments, or to otherwise honor its obligations. The risk that such issuer, guarantor or counterparty is less willing or able to do so is heightened in market environments where interest rates are changing, notably when rates are rising. The downgrade of the credit rating of a security or of the issuer of a security held by the Fund may decrease its value. Securities are subject to varying degrees of credit risk, which are often reflected in credit ratings. Measures such as average credit quality may not accurately reflect the true credit risk of the Fund. This is especially the case if the Fund consists of securities with widely varying credit ratings. Therefore, if the Fund has an average credit rating that suggests a certain credit quality, the Fund may in fact be subject to greater credit risk than the average would suggest. Credit risk is greater to the extent the Fund uses leverage or derivatives in connection with the management of the Fund, which would be magnified in the event that initial or variation margin is not provided by the counterparty to such transaction (or not provided below a certain threshold amount). Municipal bonds are subject to the risk that litigation, legislation or other political events, local business or economic conditions, or the bankruptcy of the issuer could have a significant effect on an issuer's ability to make payments of principal and/or interest. Debt instruments backed by an issuer's taxing authority may be subject to legal limits on the issuer's power to increase taxes or otherwise to raise revenue or may be dependent on legislative appropriation or government aid. Certain debt instruments are backed only by revenues derived from a particular project or source, rather than by an issuer's taxing authority, and thus may have a greater risk of default. Rising or high interest rates may deteriorate the credit quality of an issuer or a

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Prospectus

counterparty, particularly if an issuer or a counterparty faces challenges rolling or refinancing its obligations. The Fund's investments may be adversely affected if any of the issuers it is invested in are subject to an actual or perceived (whether by market participants, rating agencies, pricing services or otherwise) deterioration to their credit quality.

Credit risk includes credit spread risk, which is the risk that credit spreads (i.e., the difference in yield between securities that is due to differences in their actual or perceived credit quality) may increase when the market believes that investments generally have a greater risk of default. Increasing credit spreads may reduce the market values of the Fund's investments. Credit spreads often increase more for lower rated and unrated securities than for investment grade securities. In addition, when credit spreads increase, reductions in market value will generally be greater for longer-maturity securities. Further, credit spread duration (a measure of credit spread risk) can vary significantly from interest rate duration (e.g., for floating rate debt securities, credit spread duration typically will be higher than interest rate duration). The Fund may add credit spread duration to its portfolio, for example through the use of derivatives (e.g., credit default swaps), even while it has lower interest rate duration. The credit spread duration of the Fund may vary, in some cases significantly, from its interest rate duration.

High Yield Risk

Because the Fund may invest in high yield securitiesand unrated securitiesof similar credit quality (commonly known as "high yield securities" or "junk bonds"), it may be subject to greater levels of market risk, credit risk, call risk and liquidity risk than funds that do not invest in such securities. These securities are considered predominantly speculative by rating agencies with respect to an issuer's continuing ability to make principal and interest payments and their value may be more volatile than other types of securities. An economic downturn or individual corporate developments could adversely affect the market for these securities and reduce the Fund's ability to sell these securities at an advantageous time or price. An economic downturn could also generally lead to a higher non-payment rate and, a high yield securitymay lose significant market value before a default occurs. High yield securitiesstructured as zero-coupon bonds or pay-in-kind securities tend to be especially volatile as they are particularly sensitive to downward pricing pressures from rising interest rates or widening spreads and may require the Fund to make taxable distributions of imputed income without receiving the actual cash currency. Issuers of high yield securitiesmay have the right to "call" or redeem the issue prior to maturity, which may result in the Fund having to reinvest the proceeds in other high yield securitiesor similar instruments that may pay lower interest rates. The Fund may also be subject to greater levels of liquidity risk than funds that do not invest in high yield securities. In addition, the high yield securitiesin which the Fund invests may not be listed on any exchange and a secondary market for such securities may be comparatively illiquid relative to markets for other more liquid fixed income securities. Consequently, transactions in high yield securitiesmay involve greater costs than transactions in more actively traded securities. A lack of publicly available information, irregular trading activity and wide bid/ask spreads among other factors, may, in certain circumstances, make high yield debt more difficult to sell at an advantageous time or price than other types of securities or instruments. These factors may result in the Fund being unable to realize full value for these securities and/or may result in the Fund not receiving the proceeds from a sale of a high yield securityfor an extended period after such sale, each of which could result in losses to the Fund. In addition, adverse publicity and investor perceptions, whether or not based on fundamental analysis, may decrease the values and liquidity of high yield securities, especially in thinly traded markets. When secondary markets for high yield securitiesare less liquid than the market for other types of securities, it may be more difficult to value the securities because such valuation may require more research, and elements of judgment may play a greater role in the valuation because there is less reliable, objective data available. Because of the risks involved in investing in high yield securities, an investment in the Fund should be considered speculative.

Market Risk

The market price of securities owned by the Fund may fluctuate, sometimes rapidly or unpredictably. Securities may decline in value due to factors affecting securities markets generally or particular industries or issuers represented in the securities markets. The value of a security may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in inflation, interest or currency rates, adverse changes to credit markets or adverse investor sentiment generally. The value of a security may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously even if the performance of those asset classes is not otherwise historically correlated. Investments may also be negatively impacted by market disruptions and by attempts by other market participants to manipulate the prices of particular investments. Equity securitiesgenerally have greater price volatility than fixed income securities. Credit ratingsdowngrades may also negatively affect securities held by the Fund. Even when markets perform well, there is no assurance that the investments held by the Fund will increase in value along with the broader market.

In addition, market risk includes the risk that geopolitical and other events will disrupt the economy on a national or global level. For instance, actual or threatened war or armed conflicts, terrorism, social unrest, recessions, supply chain disruptions, market manipulation, government defaults, government shutdowns, political and regulatory changes, diplomatic developments, or the imposition of sanctions and other similar measures, including the imposition of tariffs, or other U.S. economic policies and any related public health emergencies (such as the spread of infectious

December 2, 2025 (as supplemented January 14, 2026) | Prospectus 11

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diseases, pandemics and epidemics) and natural/environmental disasters can all negatively impact the securities markets, which could cause the Fund to lose value. These events could reduce consumer demand or economic output, result in market closures, changes in interest rates, inflation/deflation, travel restrictions or quarantines, and significantly adversely impact the economy.

As computing technology and data analytics advance, there has been a trend towards machine driven and artificially intelligent trading systems, particularly with respect to increasing levels of autonomy in trading decision capabilities. Regulators of financial markets have become increasingly focused on the potential impact of artificial intelligence on investment activities and may issue regulations that affect the use of artificial technology in trading activities. Any such regulations may not have the effect on financial markets that regulators intend. Moreover, advancements in artificial intelligence and other technologies may result in the introduction of errors, defects or security vulnerabilities, which can go undetected. The potential speed of such trading and other technologies may exacerbate the impact of any such incidents, particularly where such incidents are exploited by other artificially intelligent systems designed to impair or prevent the intervention of human control.

The domestic political environment, as well as political and diplomatic events within the United States and abroad, or the U.S. government's inability at times to agree on a long-term budget and deficit reduction plan, has resulted, and may in the future result, in a government shutdown or otherwise adversely affect the U.S. regulatory landscape, the general market environment and/or investor sentiment, which could have an adverse impact on the Fund's investments and operations. Additional and/or prolonged U.S. federal government shutdowns may affect investor and consumer confidence and may adversely impact financial markets and the broader economy, perhaps suddenly and to a significant degree. Governmental and quasi-governmental authorities and regulators throughout the world have previously responded to serious economic disruptions with a variety of significant fiscal and monetary policy changes, including but not limited to, direct capital infusions into companies, new monetary programs and dramatically lower interest rates. An unexpected or sudden reversal of these policies, or the ineffectiveness of these policies, could increase volatility in securities markets, which could adversely affect the Fund's investments. Any market disruptions could also prevent the Fund from executing advantageous investment decisions in a timely manner. Funds that have focused their investments on a region enduring geopolitical market disruption will face higher risks of loss, although the increasing interconnectivity between global economies and financial markets can lead to events or conditions in one country, region or financial market adversely impacting a different country, region or financial market. Thus, investors should closely monitor current market conditions to determine whether the Fund meets their individual financial needs and tolerance for risk.

When inflationary price movements occur, fixed income securitiesmarkets may experience heightened levels of interest rate, volatility and liquidity risk. Interest rate increases in the future could cause the value of a fund that invests in fixed income securitiesto decrease, which could force the Fund to liquidate investments at disadvantageous times or prices, therefore adversely affecting the Fund and its shareholders.

Higher interest rates generally lower the values of real estate-related assets. When this does not occur as expected, it presents an increased risk of a correction or severe downturn in real estate-related asset prices, which could adversely impact the value of other investments as well, such as loans, securitized debt and other fixed income securities. Such an impact could materialize in one real estate sector and not another, or in a different manner in different real estate sectors. Examples of the risks faced by real estate-related assets include: tenant vacancy rates, increased tenant turnover and tenant concentration; general real estate headwinds, including delinquencies and difficulties in collecting rents and other payments (which increases the risk of owners being unable to pay or otherwise defaulting on their own borrowings and obligations); decreases in property values; increases in inflation, upkeep costs and other expenses; fluctuations in rents; and increased concentration in ownership of certain types of properties.

Exchanges and securities markets may close early, close late or issue trading halts on specific securities or generally, which may result in, among other things, the Fund being unable to buy or sell certain securities or financial instruments at an advantageous time or accurately price its portfolio investments. In addition, the Fund may rely on various third-party sources to calculate its NAV. As a result, the Fund is subject to certain operational risks associated with reliance on service providers and service providers' data sources. In particular, errors or systems failures and other technological issues may adversely impact the Fund's calculations of its NAV, and such NAV calculation issues may result in inaccurately calculated NAVs, delays in NAV calculation and/or the inability to calculate NAVs over extended periods. Also, because the NAV of the Fund is related to the NAVs of the PIMCO Active Fixed-Income ETFs and third-party managed funds in which it invests, the Fund may be adversely impacted by such inaccuracies, delays or other disruptions in the calculation of a PIMCO Active Fixed-Income ETF's or third-party managed fund's NAV. The Fund may be unable to recover any losses associated with such failures.

Issuer Risk

The value of a security may decline for reasons related to the issuer, such as management performance, major litigation, investigations or other controversies, changes in the issuer's financial condition or credit rating, changes in government regulations affecting the issuer or its competitive environment and strategic initiatives such as mergers, acquisitions or dispositions and the market response to any such initiatives, financial leverage, reputation or reduced demand for the issuer's goods or services, as well as the historical and prospective earnings of the issuer and the value of its assets. A change in the financial condition of a single issuer may affect one or more other issuers or securities markets as a whole. These risks can apply to the Fund and to the issuers of securities and other instruments in which the Fund invests.

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Prospectus

Liquidity Risk

The Securities and Exchange Commission (the "SEC") defines liquidity risk as the risk that the Fund could not meet requests to redeem shares issued by the Fund without significant dilution of remaining investors' interests in the Fund. Liquidity risk exists when particular investments are difficult to purchase or sell. Illiquid investmentsare investments that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. Illiquid investmentsmay become harder to value, especially in changing markets. The Fund's investments in illiquid investmentsmay reduce the returns of the Fund because it may be unable to sell the illiquid investmentsat an advantageous time or price or possibly require the Fund to dispose of other investments at unfavorable times or prices in order to satisfy its obligations, which could prevent the Fund from taking advantage of other investment opportunities. Illiquidity can be caused by, among other things, a drop in overall market trading volume, an inability to find a willing buyer, or legal restrictions on the securities' resale. Additionally, the market for certain investments may become illiquid under adverse market or economic conditions independent of any specific adverse changes in the conditions of a particular issuer, such as during political events (including periods of rapid interest rate changes). There can be no assurance that an investment that is deemed to be liquid when purchased will continue to be liquid while it is held by the Fund and/or when the Fund wishes to dispose of it. Bond markets have consistently grown over the past three decades while the capacity for traditional dealer counterparties to engage in fixed income trading has not kept pace and in some cases has decreased. As a result, dealer inventories of corporate bonds, which provide a core indication of the ability of financial intermediaries to "make markets," are at or near historic lows in relation to market size. Because market makers seek to provide stability to a market through their intermediary services, the significant reduction in dealer inventories could potentially lead to decreased liquidity and increased volatility in the fixed income markets. Such issues may be exacerbated during periods of economic uncertainty.

In such cases, the Fund, due to regulatory limitations on investments in illiquid investmentsand the difficulty in purchasing and selling such securities or instruments, may be unable to achieve its desired level of exposure to a certain sector. To the extent that the Fund's principal investment strategies involve securities of companies with smaller market capitalizations, foreign (non-U.S.) securities, Rule 144A securities, Regulation S securities, illiquid sectors of fixed income securities, derivativesor securities with substantial market and/or credit risk, the Fund will tend to have the greatest exposure to liquidity risk. Further, fixed income securitieswith longer durationsuntil maturity face heightened levels of liquidity risk as compared to fixed income securitieswith shorter durationsuntil maturity. Finally, liquidity risk refers to the risk of unusually high redemption requests, redemption requests by certain large shareholders such as institutional investors or asset allocators, or other unusual market conditions that may make it difficult for the Fund to sell investments within the allowable time period to meet redemptions. Meeting such redemption requests could require the Fund to sell securities at reduced prices or under unfavorable conditions, which would have an adverse effect on the Fund. It may also be the case that other market participants may be attempting to liquidate fixed income holdings at the same time as the Fund, causing increased supply in the market and contributing to liquidity risk and downward pricing pressure.

The action(s) of governments and regulators may have the effect of reducing market liquidity, market resiliency and money supply. Certain accounts or PIMCO affiliates may from time to time own (beneficially or of record) or control a significant percentage of the Fund's shares. Redemptions by these shareholders of their holdings in the Fund may impact the Fund's NAV and the market price and secondary market liquidity of Fund shares. These redemptions may also force the Fund to sell its securities, which may negatively impact the Fund's brokerage costs.

Liquidity risk also refers to the risk that the Fund may be required to hold additional cash or sell other investments in order to obtain cash to close out derivativesor meet the liquidity demands that derivativescan create to make payments of margin, collateral, or settlement payments to counterparties. The Fund may have to sell a security at a disadvantageous time or price to meet such obligations.

Derivatives Risk

Derivativesand other similar instruments (referred to collectively as "derivatives") are financial contracts whose value depends on, or is derived from, the value of an underlying asset, reference rate or index. The various derivativeinstruments that the Fund may use are referenced under "Characteristics and Risks of Securities and Investment Techniques-Derivatives" in this prospectus and described in more detail under "Investment Objectives and Policies" in the SAI. The Fund may use derivativesas a substitute for taking a position in the underlying asset, as part of strategies designed to gain exposure to, for example, issuers, portions of the yield curve, indexes, sectors, currencies and/or geographic regions, and/or to manage (which may mean either to increase or decrease) exposure to other risks, such as interest rate, credit or currency risk. The Fund may also use derivativesfor leverage, in which case their use would involve leveraging risk, and in some cases, may subject the Fund to the potential for unlimited loss. The use of derivativesor other similar instruments may cause the Fund's investment returns to be impacted by the performance of assets the Fund does not own, potentially resulting in the Fund's total investment exposure exceeding the value of its portfolio.

Investments in derivativesmay take the form of buying and/or writing (selling) derivatives, and/or the Fund may otherwise become an obligor under a derivativestransaction. These transactions may produce short-term capital gains in the form of premiums or other returns for the Fund (which may support, constitute and/or increase the distributions paid by, or the yield of, the Fund) but create the risk of losses that can significantly exceed such current income or other returns. For example, the premium received for writing a call option may be dwarfed by the losses the Fund may incur if the call option is exercised, and derivativetransactions where the Fund is an obligor can produce an up-front benefit, but the potential for

December 2, 2025 (as supplemented January 14, 2026) | Prospectus 13

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leveraged losses. The distributions, or distribution rate, paid by the Fund should not be viewed as the total returns or overall performance of the Fund. These strategies may also produce adverse tax consequences (for example, the Fund's income and gain-generating strategies may generate current income and gains taxable as ordinary income) and limit the Fund's opportunity to profit or otherwise benefit from certain gains. The Fund may enter into opposing derivativetransactions, or otherwise take opposing positions. Such transactions can generate distributable gains (which, as noted elsewhere, may be taxed as ordinary income) and create the risk of losses and NAV declines.

The Fund's use of derivativeinstruments involves risks different from, and possibly greater than, the risks associated with investing directly in securities and other traditional investments. Derivativesmay increase market exposure and are subject to a number of risks, such as liquidity risk (which may be heightened for highly-customized derivatives), interest rate risk, market risk, leverage risk, counterparty (including credit) risk, operational risk (such as documentation issues, settlement issues and systems failures), legal risk (such as insufficient documentation, insufficient capacity or authority of a counterparty, and issues with the legality or enforceability of a contract), management risk, risks arising from changes in applicable regulatory requirements, risks arising from margin requirements, risks arising from mispricing or valuation complexity (including the risk of improper valuation), governmental risk, risks associated with the underlying asset, reference rate or index, and risks associated with sanctions. They also involve the risk that changes in the value of a derivativeinstrument may not correlate perfectly with the underlying asset, rate or index. In this regard, the Fund may seek to achieve its investment objective, in part, by investing in derivatives that are designed to closely track the performance of an index on a daily basis. However, the overall investment strategies of the Fund are not generally designed or expected to produce returns which replicate the performance of the particular index, and the degree of variation could be substantial, particularly over longer periods. There are a number of factors which may prevent the Fund, or the derivatives or other strategies used by the Fund, from achieving desired correlation with an index, such as the impact of fees, expenses and transaction costs, the timing of pricing, and disruptions or illiquidity in the markets for derivative instruments or securities in which the Fund invests. By investing in a derivativeinstrument, the Fund could lose more than the initial amount invested and derivativesmay increase the volatility of the Fund, especially in unusual or extreme market conditions. Certain derivativeshave the potential for unlimited loss, regardless of the size of the initial investment. The Fund may utilize asset segregation and posting of collateral for risk management or other purposes. The Fund may be required to hold additional cash or sell other investments in order to obtain cash to close out a position and changes in the value of a derivativemay also create margin delivery or settlement payment obligations for the Fund. Also, suitable derivativetransactions may not be available in all circumstances and there can be no assurance that the Fund will engage in these transactions to reduce exposure to other risks when that would be beneficial or that, if used, such strategies will be successful. In addition, the Fund's use of derivativesmay increase or accelerate the amount of taxes payable by shareholders. Non-centrally-cleared over-the-counter ("OTC") derivatives are also subject to the risk that a counterparty to the transaction will not fulfill its contractual obligations to the other party, as many of the protections afforded to centrally-cleared derivativetransactions might not be available for non-centrally-cleared OTC derivatives. The primary credit risk on derivativesor other similar investments that are exchange-traded or traded through a central clearing counterparty resides with the Fund's clearing broker or the clearinghouse.

Derivativesthat are cleared by a central clearing organization can still be subject to different risks, including the creditworthiness of the central clearing organization and its members.

In addition, derivativesthat are traded on an exchange are subject to the risk that an exchange may limit the maximum daily price fluctuation of a derivativecontract and restrict or suspend trading of a contract that has reached a limit. Such limit governs only price movements of a contract during a particular trading day and therefore does not limit potential losses because the limit may work to prevent the liquidation of unfavorable positions. A daily limit may be reached for several consecutive days with little or no trading.

Participation in the markets for derivativeinstruments involves investment risks and transaction costs to which the Fund may not be subject absent the use of these strategies. The skills needed to successfully execute derivativestrategies may be different from those needed for other types of transactions. If the Fund incorrectly forecasts the value and/or creditworthiness of securities, currencies, interest rates, counterparties or other economic factors involved in a derivativetransaction, the Fund might have been in a better position if the Fund had not entered into such derivativetransaction. In evaluating the risks and contractual obligations associated with particular derivativeinstruments or other similar investments, it is important to consider that certain derivativetransactions, absent a default or termination event, may only be modified or terminated by mutual consent of the Fund and its counterparty. Therefore, it may not be possible for the Fund to modify, terminate, or offset the Fund's obligations or the Fund's exposure to the risks associated with a derivativetransaction prior to its scheduled termination or maturity date, which may create a possibility of increased volatility and/or decreased liquidity to the Fund. In such cases, the Fund may experience losses.

Because the markets for certain derivativeinstruments (including markets located in foreign countries) are relatively new and still developing, appropriate derivativetransactions may not be available in all circumstances for risk management or other purposes. Upon the expiration of a particular contract, the Fund may wish to retain its position in the derivativeinstrument by entering into a similar contract, but may be unable to do so if the counterparty to the original contract is unwilling to enter into the new contract and no other appropriate counterparty can be found. When such markets are unavailable, the Fund will be subject to increased liquidity and investment risk.

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Prospectus

When a derivativeis used as a hedge against a position that the Fund holds, any loss generated by the derivativegenerally should be substantially offset by gains on the hedged investment, and vice versa. Although hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivativeand the underlying instrument, and there can be no assurance that the Fund's hedging transactions will be effective. Derivativesused for hedging or risk management may not operate as intended or may expose the Fund to additional risks. In addition, derivativesused for hedging may partially protect the Fund from the risks they were intended to hedge yet not fully mitigate the impact of such risks.

The regulation of the derivativesmarkets has increased over time, and additional future regulation of the derivativesmarkets may make derivativesmore costly, may limit the availability or reduce the liquidity of derivatives, or may otherwise adversely affect the value or performance of derivatives. Any such adverse future developments could impair the effectiveness or raise the costs of the Fund's derivativetransactions, impede the employment of the Fund's derivativesstrategies, or adversely affect the Fund's performance and cause the Fund to lose value.

When the Fund obtains indirect exposure to another fund through derivatives, the investing fund will bear expenses embedded within the derivative, which generally would be expected to include the fees and expenses of the underlying fund as well as other expenses, such as those imposed by a counterparty or clearing agency. These accumulated costs and expenses will detract from the gross performance of the derivative and a fund's economic returns for such an investment will be net of these fees and expenses. Unlike direct investment in shares of the underlying funds, these expenses will not be considered acquired fund fees and expenses and therefore will not be included in the Fund's Annual Fund Operating Expenses table. PIMCO will not waive any expenses of an underlying PIMCO fund that are embedded within the derivativefrom the investing fund's management fees. As a result, PIMCO may receive management fee revenue from the increase in assets in the underlying PIMCO fund associated with any hedging activity by the counterparty to the investing fund's derivatives, as it is common for such counterparties to hedge their derivativesexposure by investing directly in the underlying reference asset, which are in addition to the Fund's management fees.

Issuer Non-Diversification Risk

Focusing investments on a small number of issuers increases risk. Funds that are "non-diversified" may invest a greater percentage of their assets in the securities of a single issuer (such as bonds issued by a particular state) than funds that are "diversified." Funds that invest in a relatively small number of issuers are more susceptible to risks associated with a single economic, political or regulatory occurrence than a more diversified portfolio might be. Some of those issuers also may present substantial credit or other risks.

Exchange-Traded Fund ("ETF") Risk

Investments in ETFs entail certain risks. In the case of actively managed ETFs, there is a risk that the ETF may not achieve its investment objective. Investments in ETFs designed to track an index involve the risk that the ETF's performance may not track the performance of the index the ETF is designed to track. This deviation may occur due to cash inflows and outflows from and to investors buying and redeeming shares or due to occasional differences between the composition of the index and the securities held by the ETF. In addition, investments in ETFs involve the risk that the market prices of ETF shares will fluctuate, sometimes rapidly and materially, in response to changes in the ETF's NAV, the value of ETF holdings and supply and demand for ETF shares. Although ETFs will generally trade close to NAV, market volatility, lack of an active trading market for ETF shares, disruptions at market participants (such as authorized participants or market makers) and any disruptions in the ordinary functioning of the creation/redemption process may result in ETF shares trading significantly above (at a "premium") or below (at a "discount") NAV. Significant losses may result when transacting in ETF shares in these and other circumstances.

Equity Risk

Equity or equity-related securities represent an ownership interest, or the right to acquire an ownership interest, in an issuer. Equity or equity-related securities also include, among other things, common stocks, preferred securities, convertible stocks and warrants. The values of equity securities, such as common stocks and preferred securities, may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in inflation, interest or currency rates, or adverse investor sentiment generally. They may also decline due to factors that affect a particular industry or industries, such as regulatory changes, labor shortages or increased production costs and competitive conditions within an industry. Conversely, a change in financial condition or other event affecting a single issuer or industry may adversely impact securities markets as a whole. In addition, preferred securities may be subject to greater credit risk or other risks, such as risks related to deferred and omitted distributions, limited voting rights, liquidity, interest rates, regulatory changes and special redemption rights. Equity or equity-related securities generally have greater price volatility than most fixed income securities. These risks are generally magnified in the case of equity investments in distressed companies.

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PIMCO ETF Trust

Mortgage-Related and Other Asset-Backed Securities Risk

Mortgage-related and other asset-backed securitiesrepresent interests in "pools" of mortgages or other assets such as consumer loans or receivables held in trust and often involve risks that are different from or possibly more acute than risks associated with other types of debt instruments. Generally, rising interest rates tend to extend the duration of fixed rate mortgage-related securities, making them more sensitive to changes in interest rates. Compared to other fixed income investments with similar maturity and credit, mortgage-related securitiesmay increase in value to a lesser extent when interest rates decline and may decline in value to a similar or greater extent when interest rates rise. As a result, in a period of rising interest rates, if the Fund holds mortgage-related securities, it may exhibit additional volatility since individual mortgage holders are less likely to exercise prepayment options, thereby putting additional downward pressure on the value of these securities and potentially causing the Fund to experience losses. This is known as extension risk. Mortgage-backed securities can be highly sensitive to rising interest rates, such that even small movements can cause an investing Fund to lose value. Mortgage-backed securities, and in particular those not backed by a government guarantee, are subject to credit risk. In addition, adjustable and fixed rate mortgage-related securitiesare subject to prepayment risk. When interest rates decline, borrowers may pay off their mortgages sooner than expected. This can reduce the returns of the Fund because the Fund may have to reinvest that money at the lower prevailing interest rates. In addition, the creditworthiness, servicing practices, and financial viability of the servicers of the underlying mortgage pools present significant risks. For instance, a servicer may be required to make advances in respect of delinquent loans underlying the mortgage-related securities; however, servicers experiencing financial difficulties may not be able to perform these obligations. Additionally, both mortgage-related and asset-backed securitiesare subject to risks associated with fraud or negligence by, or defalcation of, their servicers. These securities are also subject to the risks of the underlying loans. In some circumstances, a servicer's or originator's mishandling of documentation related to the underlying collateral (e.g., failure to properly document a security interest in the underlying collateral) may affect the rights of security holders in and to the underlying collateral. In addition, the underlying loans may have been extended pursuant to inappropriate underwriting guidelines, to no underwriting guidelines at all, or to fraudulent origination practices. The owner of a mortgage-backed security's ability to recover against the sponsor, servicer or originator is uncertain and is often limited.

The Fund's investments in other asset-backed securitiesare subject to risks similar to those associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets. Payment of principal and interest on asset-backed securitiesmay be largely dependent upon the cash flows generated by the assets backing the securities, and asset-backed securitiesmay not have the benefit of any security interest in the related assets. The Fund may invest in any tranche of mortgage-related and other asset-backed securities, including junior and/or equity tranches (to the extent consistent with the Fund's guidelines), which generally carry higher levels of the foregoing risks. Additionally, to the extent the Fund invests directly in mortgages and other types of collateral (consistent with its investment guidelines), the Fund would be subject to risks similar (and in some cases to a greater degree) to those described above.

Foreign (Non-U.S.) Investment Risk

Foreign (non-U.S.) securities may experience more rapid and extreme changes in value than securities of U.S. issuers or securities that trade exclusively in U.S. markets. The securities markets of many foreign (non-U.S.)countries are relatively small, with a limited number of companies representing a small number of industries. Additionally, issuers of foreign (non-U.S.) securitiesare usually not subject to the same degree of regulation as U.S. issuers. Reporting, legal, corporate governance, accounting and auditing standards of foreign (non-U.S.)countries differ, in some cases significantly, from U.S. standards. Global economies and financial markets are becoming increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. Foreign (non-U.S.) market trading hours, clearance and settlement procedures, and holiday schedules may limit the Fund's ability to buy and sell securities. Investments in foreign (non-U.S.)markets may also be adversely affected by governmental actions such as the imposition of capital controls, nationalization of companies or industries, expropriation of assets or the imposition of punitive taxes. The governments of certain countries may prohibit or impose substantial restrictions on foreign investing in their capital markets or in certain sectors or industries. In addition, a foreign (non-U.S.)government may limit or cause delay in the convertibility or repatriation of its currency which would adversely affect the U.S. dollar value and/or liquidity of investments denominated in that currency. Certain foreign (non-U.S.)investments may become less liquid in response to market developments or adverse investor perceptions, or become illiquid after purchase by the Fund, particularly during periods of market turmoil and may render holdings in that foreign (non-U.S.)country illiquid or even worthless. A reduction in trading in securities of issuers located in countries whose economies are heavily dependent upon trading with key partners may have an adverse impact on the Fund's investments. Additionally, events and evolving conditions in certain markets or regions may alter the risk profile of investments tied to those markets or regions. This may cause investments tied to such markets or regions to become riskier or more volatile, even when investments in such markets or regions were perceived as comparatively stable historically.

Also, nationalization, expropriation or confiscatory taxation, unstable governments, decreased market liquidity, currency blockage, market disruptions, political changes, security suspensions, diplomatic developments, trade restrictions (including tariffs) or the imposition of sanctions or other similar measures could adversely affect the Fund's investments in a foreign (non-U.S.)country and may render holdings in that foreign (non-U.S.) country illiquid or even worthless. In the event of nationalization, expropriation or other confiscation, the Fund could lose its entire investment in

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Prospectus

foreign (non-U.S.) securities. The type and severity of sanctions and other similar measures, including counter sanctions and other retaliatory actions, that may be imposed could vary broadly in scope, and their impact is difficult to ascertain. These types of measures may include, but are not limited to, banning a sanctioned country or certain persons or entities associated with such country from global payment systems that facilitate cross-border payments, restricting securities transactions, restricting dealings with entities that are critical to the infrastructure of securities and related transactions in specific jurisdictions, restricting transactions in specified sectors of certain countries, and freezing the assets of particular countries, entities or persons. The imposition of sanctions and other similar measures could, among other things, result in a decline in the value and/or liquidity of affected securities, downgrades in the credit ratings of affected or related securities, currency devaluation or volatility, and increased market volatility and disruption in the securities or sanctioned country and throughout the world. Sanctions and other similar measures could directly or indirectly limit or prevent the Fund from buying and selling securities, receiving interest or principal payments due on the securities, significantly delay or prevent the settlement of securities transactions and adversely impact the Fund's liquidity and performance and/or prevent the liquidation of the Fund holding sanctioned securities. The U.S. government may renegotiate some of its global trade relationships with foreign governments and may impose or threaten to impose significant tariffs. The imposition of tariffs, trade restrictions, currency restrictions or similar actions (or retaliatory measures taken in response to such actions) could contribute to volatility or overall declines in the U.S. and global investment markets. Adverse conditions in a certain region can adversely affect securities of other countries whose economies appear to be unrelated. To the extent the Fund invests a significant portion of its assets in a specific geographic region or in securities denominated in a particular foreign (non-U.S.)currency, the Fund will generally have more exposure to regional economic risks, including weather emergencies and natural disasters, associated with foreign (non-U.S.)investments. Foreign (non-U.S.) securitiesmay also be less liquid (particularly during market closures due to local holidays or other reasons) and more difficult to value than securities of U.S. issuers.

Emerging Markets Risk

Foreign (non-U.S.) investment risk may be particularly high to the extent the Fund invests in emerging market securities. Emerging market securitiesmay present market, credit, currency, liquidity, volatility, legal, political, technical, headline, reputational, and other risks different from, and potentially greater than, the risks of investing in securities and instruments economically tied to developed foreign countries. To the extent the Fund invests in emerging market securitiesor other investments that are economically tied to a particular region, country or group of countries, the Fund may be more sensitive to adverse political, social, environmental and health events affecting that region, country or group of countries. Economic, business, political or social instability may affect emerging market securitiesdifferently, and often more severely, than developed market securities. A Fund that focuses its investments in multiple asset classes of emerging market securitiesmay have a limited ability to mitigate losses in an environment that is adverse to emerging market securitiesin general. Emerging market securitiesmay also be more volatile, less liquid (particularly during market closures due to local holidays or other reasons) and more difficult to value than securities economically tied to developed foreign countries. The systems and procedures for trading and settlement of securities in emerging markets are less developed and less transparent and transactions may take longer to settle. Emerging market countries typically have less established regulatory, disclosure, legal, accounting, recordkeeping and financial reporting systems than those in more developed markets, which may increase the potential for market manipulation or reduce the scope or quality of financial information available to investors. Governments in emerging market countries are often less stable and more likely to take extra-legal action with respect to companies, industries, assets, or foreign ownership than those in more developed markets. Moreover, it can be more difficult for investors to bring litigation or enforce judgments, or to obtain information needed to pursue or enforce such judgments, against issuers in emerging markets or for U.S. regulators to bring enforcement actions against such issuers. In addition, foreign companies with securities listed on U.S. exchanges may be delisted if they do not meet U.S. accounting standards and auditor oversight requirements, which may decrease the liquidity and value of the securities. Emerging markets may also be more susceptible to fraud, corruption, money laundering and economic sanctions risk, which may result in negative commercial consequences in relation to the value, liquidity and tradability of investments in or related to those regions. The Fund will also be subject to Emerging Markets Risk if it invests in derivativesor other securities or instruments whose value or return are related to the value or returns of emerging markets securities. Rising interest rates, combined with widening credit spreads, could negatively impact the value of emerging market debt and increase funding costs for foreign issuers. In such a scenario, foreign issuers might not be able to service their debt obligations, the market for emerging market debt could suffer from reduced liquidity, and any investing Fund could experience losses. The economy of some emerging markets may be particularly exposed to or affected by a certain industry or sector, and therefore issuers and/or securities of such emerging markets may be more affected by the performance of such industries or sectors.

Sovereign Debt Risk

Sovereign debt risk is the risk that fixed income instrumentsissued by sovereign entities may decline in value as a result of default or other adverse credit events resulting from an issuer's inability or unwillingness to make principal or interest payments in a timely fashion. A sovereign entity's failure to make timely payments on its debt can result from many factors, including, without limitation, insufficient foreign (non-U.S.) currencyreserves or an inability to sufficiently manage fluctuations in relative currency valuations, an inability or unwillingness to satisfy the demands of creditors and/or relevant supranational entities regarding debt service or economic reforms, the size of the debt burden relative to economic output and tax revenues, cash flow difficulties, and other political and social considerations. The risk of loss to the Fund in the event of a

December 2, 2025 (as supplemented January 14, 2026) | Prospectus 17

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sovereign debt default or other adverse credit event is heightened by the unlikelihood of any formal recourse or means to enforce its rights as a holder of the sovereign debt. In addition, sovereign debt restructurings, which may be shaped by entities and factors beyond the Fund's control, may result in a loss in value of the Fund's sovereign debt holdings.

Currency Risk

If the Fund invests directly in foreign (non-U.S.) currenciesor in securities that trade in, and receive revenues in, foreign (non-U.S.) currencies, or in derivatives or other instruments that provide exposure to foreign (non-U.S.) currencies, it will be subject to the risk that those currencies will decline in value relative to the U.S. dollar, or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency being hedged. Although the Fund may attempt to hedge its currency exposure into the U.S. dollar, it may not be successful in reducing the effects of currency fluctuations. The Fund may also hedge from one foreign currency to another. In addition, the Fund's use of currency hedging may not be successful and the use of such strategies may lower the Fund's potential returns.

Currency rates in foreign (non-U.S.) countries may fluctuate significantly over short periods of time for a number of reasons, including due to changes in interest or inflation rates, balance of payments and governmental surpluses or deficits, intervention (or the failure to intervene) by U.S. or foreign (non-U.S.) governments, central banks or supranational entities such as the International Monetary Fund, the imposition of currency controls or other political developments in the U.S. or abroad. As a result, the Fund's investments in or exposure to foreign (non-U.S.) currenciesand/or foreign (non-U.S.) currency-denominated securities may reduce the returns of the Fund. Devaluation of a currency by a country's government or banking authority can significantly impact the value of any investments denominated in that currency. The Fund may also be adversely impacted by expenses incurred by converting between currencies to purchase and sell securities not valued in the U.S. dollar, as well as by currency restrictions, exchange control regulation, or governmental restrictions that limit or otherwise delay the Fund's ability to convert currencies.

Currency risk may be particularly high to the extent that the Fund invests in foreign (non-U.S.) currenciesor engages in foreign currency transactionsthat are economically tied to emerging market countries. These currency transactions may present market, credit, currency, liquidity, legal, political and other risks different from, or greater than, the risks of investing in developed foreign (non-U.S.) currenciesor engaging in foreign currency transactionsthat are economically tied to developed foreign countries.

Leveraging Risk

Certain transactions may give rise to a form of leverage. Such transactions may include, among others, reverse repurchase agreements, loans of portfolio securities,and the use of when-issued, delayed delivery or forward commitment transactions. The use of derivativesmay also create leveraging risk. A Fund also may be exposed to leveraging risk by borrowingmoney for investment purposes and by the Fund's portfolio providing fixed income exposure that is in addition to the targeted equity returns of the Fund. Leverage may cause the Fund to liquidate portfolio positions to satisfy its obligations when it may not be advantageous to do so. Leverage, including borrowing, may cause the Fund to be more volatile than if the Fund had not been leveraged. This is because leverage tends to exaggerate the effect of any increase or decrease in the value of the Fund's portfolio securities. The use of leverage may also increase the Fund's sensitivity to interest rate risks. Certain types of leveraging transactions, such as short salesthat are not "against the box" (i.e., short sales where the Fund does not hold the security or have the right to acquire it without payment of further consideration), could theoretically be subject to unlimited losses in cases where the Fund, for any reason, is unable to close out the transaction. In addition, to the extent the Fund borrows money, interest costs on such borrowingsmay not be recovered by any appreciation of the securities purchased with the borrowed amounts and could exceed the Fund's investment returns, resulting in greater losses. Moreover, to make payments of interest and other loan costs, the Fund may be forced to sell portfolio securities when it is not otherwise advantageous to do so. When the Fund reduces or discontinues its use of leverage ("deleveraging"), it may be required to sell portfolio securities at inopportune times to repay leverage obligations, which could result in realized losses and a decrease in the Fund's net asset value. Deleveraging involves complex operational processes, including the coordination of asset sales, repayment of debt, and potential restructuring of the Fund's capital and may involve significant costs, including transaction costs associated with the sale of portfolio securities and prepayment penalties on borrowed funds. Leveraging transactions pursued by the Fund may increase its durationand sensitivity to interest rate changes and other market risks. The Fund may continue to use leverage even if available financing rates are higher than anticipated returns, including, for example, in cases where deleveraging, including any expenses related thereto, might be viewed as detrimental to the Fund's portfolio.

Management Risk

The Fund is subject to management risk because they are an actively managed investment portfolio. PIMCO and each individual portfolio manager will apply investment techniques and risk analysis and will, in some cases, rely partially or entirely upon or be informed by one or more quantitative models in making investment decisions for the Fund. PIMCO and each portfolio manager may not consider every factor or may determine that certain factors are more significant than others. There can be no guarantee that these decisions will produce the desired results or that the due diligence conducted by PIMCO and individual portfolio managers will evaluate every factor prior to investing in a company or issuer and expose all material risks associated with an investment. Additionally, PIMCO and individual portfolio managers may not be able to identify suitable investment

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Prospectus

opportunities and may face competition from other investment managers when identifying and consummating certain investments. Certain securities or other instruments in which the Fund seeks to invest may not be available in the quantities desired, including in circumstances where other funds for which PIMCO acts as investment adviser, including funds with names, investment objectives and policies, and/or portfolio management teams, similar to the Fund, are seeking to invest in the same or similar securities or instruments. In addition, regulatory restrictions, actual or potential conflicts of interest or other considerations may cause PIMCO to restrict or prohibit participation in certain investments. In such circumstances, PIMCO or the individual portfolio managers may determine to purchase other securities or instruments as substitutes. Such substitute securities or instruments may not perform as intended, which could result in losses to the Fund. To the extent the Fund employs strategies targeting perceived pricing inefficiencies, arbitrage strategies or similar strategies, it is subject to the risk that the pricing or valuation of the securities and instruments involved in such strategies may change unexpectedly, which may result in reduced returns or losses to the Fund. The Fund is also subject to the risk that deficiencies in the internal systems or controls of PIMCO or another service provider will cause losses for the Fund or hinder Fund operations. For example, trading delays or errors (both human and systemic) could prevent the Fund from purchasing a security expected to appreciate in value. Please refer to "Portfolio Managers - Conflicts of Interest" in the SAI for further information. Additionally, actual or potential conflicts of interest, legislative, regulatory, or tax restrictions, policies or developments may affect the investment techniques available to PIMCO and each individual portfolio manager in connection with managing the Fund may cause PIMCO to restrict or prohibit participation in certain investments and may also adversely affect the ability of the Fund to achieve its investment objective. There also can be no assurance that all of the personnel of PIMCO will continue to be associated with PIMCO for any length of time. The loss of services of one or more key employees of PIMCO could have an adverse impact on the Fund's ability to realize its investment objective.

Model Risk

In making investment allocation decisions for the Fund, PIMCO may utilize quantitative models that may be proprietary or developed by third-parties. These models are used by PIMCO to determine (or assist in determining) the Fund's target asset allocation and to identify potentially attractive relative value and risk hedging strategies. The investment models used in making investment allocation decisions may not adequately take into account certain factors, may contain design flaws or faulty assumptions, and may rely on incomplete or inaccurate data inputs, any of which may result in a decline in the value of an investment in the Fund. There can be no assurance that the models used by PIMCO will remain viable, due to various factors, which may include the quality of the data input into the models and the assumptions underlying such models, which to varying degrees involve the exercise of judgment, as well as the possibility of errors in constructing or using the model.

Models rely on accurate market data inputs. If inaccurate market data is entered into a model, the resulting information will be incorrect. In addition, the models used may be predictive in nature and such models may result in an incorrect assessment of future events. The models evaluate securities or securities markets based on certain assumptions concerning the interplay of market factors. The markets or the prices of individual securities may be affected by factors not foreseen in developing the models. In addition, when relying on a quantitative model and/or data supplied by third parties, PIMCO may have less insight into the construction, coding or testing of the third-party model or data, and PIMCO will be exposed to systems, cyber security and other risks associated with the third party that provides the model or data.

The use of models can be complex and involves financial, economic, econometric and statistical theories, research and modeling; and the results of those processes must then be translated into computer code. Although PIMCO seeks to hire individuals and/or third parties, as applicable, skilled in each of these functions and to provide appropriate levels of oversight, the complexity of the individual tasks, the difficulty of integrating such tasks, and the limited ability to perform "real world" testing of a model's end product raises the chances that a finished model may contain an error; one or more of such errors could adversely affect the Fund's performance.

Futures Contract Risk

A futures contract is an exchange-traded contract to buy or sell an underlying asset, such as a security, currency or commodity, for a set price on a future date. The risks associated with the Fund's use of derivative instruments, including futures contracts, are discussed in more detail under "Characteristics and Risks of Securities and Investment Techniques- Derivatives" in this prospectus and under "Investment Objectives and Policies" in the SAI. The purchase or sale of a futures contract may result in losses in excess of the amount invested in the futures contract. There can be no guarantee that there will be a correlation between price movements in the futures contract and the underlying asset. In addition, there are significant differences between the futures market and the markets for underlying assets, which could result in an imperfect correlation between the markets. The degree of imperfect correlation depends on circumstances such as variations in speculative market demand for futures and futures options on underlying assets, including technical influences in futures trading and futures options, and differences between the futures contract and underlying asset due to factors such as interest rate levels, maturities, and creditworthiness of issuers.

Futures contracts are traded on exchanges, so that, in most cases, a party can close out its position on the exchange for cash, without delivering the underlying asset. Because the futures utilized by the Fund are exchange-traded, the primary credit risk on futures contracts resides with the Fund's clearing broker or the clearinghouse. Changes in regulation relating to a registered fund's use of derivatives and related instruments could potentially limit or impact the Fund's ability to invest in derivatives, limit the Fund's ability to employ certain strategies that use derivatives and/or adversely affect

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the value of derivatives and the Fund's performance. Futures exchanges may limit the amount of fluctuation permitted in certain futures contract prices during a single trading day. There can be no assurance that a liquid market will exist at a time when the Fund seeks to close out a futures or a futures option position, and that the Fund would remain obligated to meet margin requirements until the position is closed.

In addition, certain futures contracts may be relatively new instruments without a significant trading history. As a result, there can be no assurance that an active secondary market will develop or continue to exist.

Short Exposure Risk

The Fund's short sales and short positions, if any, are subject to special risks. A short saleinvolves the sale by the Fund of a security that it does not own with the hope of purchasing the same security at a later date at a lower price. The Fund may also enter into a short position through a forward commitment or a short derivativeposition through a futures contract or swap agreement. If the price of the security or derivativehas increased during this time, then the Fund will incur a loss equal to the increase in price from the time that the short salewas entered into plus any transaction costs (i.e., premiums and interest) paid to the broker-dealer to borrow securities. Therefore, short salesinvolve the risk that losses may be exaggerated, potentially losing more money than the actual cost of the investment. By contrast, a loss on a long position arises from decreases in the value of the security and is limited by the fact that a security's value cannot decrease below zero.

By investing the proceeds received from selling securities short, the Fund could be deemed to be employing a form of leverage, which creates special risks. The use of leverage may increase the Fund's exposure to long security positions and make any change in the Fund's NAV greater than it would be without the use of leverage. This could result in increased volatility of returns. There is no guarantee that any leveraging strategy the Fund employs will be successful during any period in which it is employed.

In times of unusual or adverse market, economic, regulatory, environmental or political conditions, the Fund may not be able, fully or partially, to implement its short selling strategy. Periods of unusual or adverse market, economic, regulatory, environmental or political conditions generally may exist for as long as six months and, in some cases, much longer. In response to market events, the SEC and regulatory authorities in other jurisdictions may adopt (and in certain cases, have adopted) bans on, and/or reporting requirements for, short salesof certain securities, including short positions on such securities acquired through swaps. Restrictions on and/or reporting requirements applicable to short selling and short positions may negatively impact and materially impair a Fund's ability to execute certain transactions. Also, there is the risk that the third party to the short sale or short position will not fulfill its contractual obligations, causing a loss to the Fund.

Collateralized Loan Obligations Risk

The Fund may invest in collateralized loan obligations ("CLOs") and other similarly structured investments. A CLO is an asset-backed security typically collateralized by a pool of loans, which may include, among others, domestic and foreign senior secured loans, senior unsecured loans and subordinate corporate loans, including loans that may be rated below investment grade or equivalent unrated loans. In addition to the risks associated with investment in such underlying assets, the structure and characteristics of a CLO present certain additional risks. The Fund's investments in CLOs and other similarly structured investments may expose the Fund to heightened credit risk, interest rate risk, liquidity risk, market risk and prepayment and extension risk, as well as the risk of default on the underlying asset. In addition, investments in CLOs carry additional risks including, but not limited to: (i) the possibility that distributions from the collateral securities will not be adequate to make interest or other payments; (ii) the quality of the collateral may decline in value or default; (iii) risks related to the capability of the servicer of the securitized assets; (iv) the risk that the Fund may invest in tranches of CLOs that are subordinate to other tranches; (v) the structure and complexity of the transaction and the legal documents may not be fully understood at the time of investment and could lead to disputes with the issuer or among investors regarding the characterization of proceeds or unexpected investment results; and (vi) the CLO's manager may perform poorly. CLOs may charge management and other administrative fees, which are in addition to those of the Fund.

The cash flows from a CLO are split into portions, called tranches, varying in risk and yield. Losses caused by defaults on underlying assets are borne first by the holders of subordinate tranches. Tranches are categorized as senior, mezzanine and subordinated/equity, according to their degree of risk. Interest on a CLO may be paid in kind or deferred and capitalized (paid in the form of obligations of the same type rather than cash), which involves continued exposure to default risk with respect to such payments. If there are defaults or the CLO's collateral otherwise underperforms, scheduled payments to senior tranches take precedence over those of mezzanine tranches, and scheduled payments to mezzanine tranches take precedence over those of subordinated/equity tranches. The riskiest portion is the "equity" tranche which bears the first loss of any defaults from the underlying bonds or loans although more senior tranches may also bear losses. Since they are partially protected from defaults, senior tranches from a CLO typically have higher ratings and lower yields than their underlying securities, and can be rated investment grade. Despite the protection from the equity tranche, CLO tranches can experience substantial losses due to actual defaults, increased sensitivity to defaults due to collateral default and disappearance of protecting tranches, market anticipation of defaults, as well as aversion to CLO securities as a class.

The risks of an investment in a CLO depend largely on the type of the collateral securities and the class of the instrument in which the Fund invests. Typically, CLOs are privately offered and sold, and thus, are not registered under the securities laws.

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Tax-Efficient Investing Risk

The Fund may engage in investment strategies intended to manage the tax consequences of the Fund's investments. Any such strategy may be unsuccessful or only partially successful, and investors may experience adverse tax effects, including, but not limited to potentially greater tax liability than other PIMCO-advised funds. Changes to federal, state or local tax laws could also have an adverse effect on the Fund's tax-efficient approach. Additionally, such strategies may reduce investment returns or result in investment losses, which could cause the Fund and investors to experience losses. Further, the Fund may realize taxable gains in order to satisfy cash redemptions or incur other tax consequences of transactions that PIMCO otherwise believes are beneficial to the Fund.

Turnover Risk

A change in the securities held by the Fund is known as "portfolio turnover." Higher portfolio turnover involves correspondingly greater expenses to the Fund, including brokerage commissions or dealer mark-ups and other transaction costs on the sale of securities and reinvestments in other securities. Such sales may also result in realization of taxable capital gains, including short-term capital gains (which are generally taxed as ordinary income when distributed to individual shareholders), and may adversely impact the Fund's after-tax returns. The trading costs and tax effects associated with portfolio turnover may adversely affect the Fund's performance.

Tracking Error Risk

To the extent the Equity Portfolio of the Fund seeks to track the investment results of a group of issuers' equity securities, it may not invest in every component security of the group of issuers' equity securities. Imperfect correlation between the Fund's Equity Portfolio and the group of issuers' equity securities, asset valuation, timing variances, changes to the group of issuers' equity securities and regulatory requirements may cause the Equity Portfolio's performance to diverge from the performance of the group of issuers' equity securities. Tracking error may also result because the Fund incurs fees and expenses while the group of issuers' equity securities does not incur such fees and expenses. Such expenses include the costs of buying and selling securities, such as when the Fund rebalances its Equity Portfolio to reflect changes in the composition of the group of issuers' equity securities. The performance of the Fund's Equity Portfolio and the group of issuers' equity securities may vary due to differences between the Fund's portfolio and the group of issuers' equity securities due to legal restrictions, cost or liquidity restraints. The risk that performance of the Fund's Equity Portfolio and the group of issuers' equity securities may be heightened during periods of market volatility or other unusual market conditions. Because a group of issuers' equity securities is not subject to the tax diversification requirements to which the Fund must adhere, the Fund may be required to deviate its investments from the securities and relative weightings of the group of issuers' equity securities. For tax efficiency purposes, the Fund may sell certain securities to realize losses, which will result in a deviation from the group of issuers' equity securities. The Fund may not be fully invested at times either as a result of cash flows into the Fund or reserves of cash held by the Fund to meet redemptions and to pay expenses. In addition, to the extent an underlying fund uses a representative sampling approach, such underlying fund's returns may be less correlated to the return of the group of issuers' equity securities than if the underlying fund held all of the securities in the group of issuers' equity securities.

Indexing Risk

The Fund's Equity Portfolio may use an indexing approach and may be affected by a general decline in market segments or asset classes relating to a group of issuers' equity securities. To the extent that the Fund's Equity Portfolio does use an indexing approach, it invests in securities and instruments included in, or representative of, a group of issuers' equity securities regardless of the investment merits of the group of issuers' equity securities. Generally, the index provider does not provide any warranty, or accept any liability, with respect to the quality, accuracy, or completeness of either the group of issuers' equity securities or its related data.

Additionally, errors in the construction, calculation or transmission of the group of issuers' equity securities may occur from time to time, and the index provider may not identify or correct such errors for some period of time or at all. Any such construction, calculation or transmission error may adversely impact the Fund's Equity Portfolio, and any gains from such errors will be kept by the Fund and any losses or costs resulting from such errors will be borne by the Fund.

Additionally, unusual market conditions may cause the index provider to postpone a scheduled rebalance or reconstitution, which could cause the group of issuers' equity securities to vary from its normal or expected composition. This means that, based on market and economic conditions, the performance of the Fund's Equity Portfolio could be lower than funds that may actively shift their portfolio assets to take advantage of market opportunities or to lessen the impact of a market decline or a decline in the value of one or more issuers.

Disclosure of Portfolio Holdings

Please see "Disclosure of Portfolio Holdings" in the SAI for information about the availability of the complete schedule of the Fund's holdings.

December 2, 2025 (as supplemented January 14, 2026) | Prospectus 21

PIMCO ETF Trust

Management of the Fund

Investment Manager

PIMCO serves as the investment manager for the Fund. Subject to the supervision of the Board of Trustees, PIMCO is responsible for managing the investment activities of the Fund and the Fund's business affairs and other administrative matters.

PIMCO is located at 650 Newport Center Drive, Newport Beach, CA 92660. Organized in 1971, PIMCO provides investment management and advisory services to private accounts of institutional and individual clients and to mutual funds. As of September 30, 2025, PIMCO had approximately $2.20 trillion in assets under management, including $1.78 trillion in third-party client assets. Assets include $82.1 billion (as of June 30, 2025) in assets managed by Prime Real Estate (formerly Allianz Real Estate), an affiliate and wholly-owned subsidiary of PIMCO and PIMCO Europe GmbH, that includes PIMCO Prime Real Estate GmbH, PIMCO Prime Real Estate LLC and their subsidiaries and affiliates. PIMCO Prime Real Estate LLC investment professionals provide investment management and other services as dual personnel through Pacific Investment Management Company LLC. PIMCO Prime Real Estate GmbH operates separately from PIMCO.

Management Fees

The Fund pays for the advisory and supervisory and administrative services it requires under what is essentially an all-in fee structure. The Fund pays monthly Management Fees to PIMCO at the following annual rate (stated as a percentage of the average daily net assets of the Fund taken separately) of 0.35%.

In addition to providing investment advisory services, PIMCO provides or procures supervisory and administrative services for shareholders and also bears the costs of various third-party services required by the Fund, including audit, custodial, portfolio accounting, legal, transfer agency and printing costs. The Fund bears other expenses which are not covered under the management fee which may vary and affect the total level of expenses paid by shareholders, such as taxes and governmental fees, brokerage fees, commissions and other transaction expenses (including, without limitation, fees and expenses of outside legal counsel or third-party consultants retained in connection with reviewing, negotiating and structuring specialized loans and other investments made by a Fund, and any costs associated with originating loans, asset securitizations, alternative lending-related strategies and so-called "broken-deal costs" (e.g., fees, costs, expenses and liabilities, including, for example, due diligence-related fees, costs, expenses and liabilities, with respect to unconsummated investments)), organizational and offering expenses of the Trust and the Fund, and any other expenses which are capitalized in accordance with generally accepted accounting principles, costs of borrowing money, including interest expenses, securities lending expenses, extraordinary expenses (such as litigation and indemnification expenses) and fees and expenses of the Trust's Independent Trustees and their counsel. PIMCO generally earns a profit on the management fee paid by the Fund. Also, under the terms of the investment management agreement, PIMCO, and not Fund shareholders, would benefit from any price decreases in third-party services, including decreases resulting from an increase in net assets.

A discussion regarding the basis for the Board of Trustees' approval of the Fund's investment management agreement is available in the Fund's report filed on Form N-CSR.

Expense Limitation Agreement

PIMCO has contractually agreed, through October 31, 2027, to waive a portion of the Fund's Management Fee, or reimburse the Fund, to the extent that the Fund's organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata share of Trustee fees exceed 0.0049% (the "Expense Limit") (calculated as a percentage of the Fund's average daily net assets). The Expense Limitation Agreement will automatically renew for one-year terms unless PIMCO provides written notice to the Trust at least 30 days prior to the end of the then current term. In any month in which the investment management agreement is in effect, PIMCO is entitled to reimbursement by the Fund of any portion of the Management Fee waived or reimbursed as set forth above (the "Reimbursement Amount") within thirty-six months of the time of the waiver, provided that such amount paid to PIMCO will not: 1) together with any organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustee fees, exceed, for such month, the Expense Limit (or the amount of the expense limit in place at the time the amount being recouped was originally waived if lower than the Expense Limit); 2) exceed the total Reimbursement Amount; or 3) include any amounts previously reimbursed to PIMCO.

Fee Waiver Agreement

PIMCO has contractually agreed, through October 31, 2027, to waive or reduce its management fee by 0.20% of the average daily net assets of the Fund. In any month in which the investment management agreement is in effect, PIMCO is entitled to reimbursement by the Fund of any portion of the management fee waived as set forth above (the "Fee Waiver Reimbursement Amount") within thirty-six months of the time of the waiver, provided that such amount paid to PIMCO will not: 1) together with any recoupment of organizational expenses, pro rata share of expenses related to

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obtaining or maintaining a Legal Entity Identifier and pro rata Trustee fees pursuant to the Expense Limitation Agreement, exceed the Expense Limit (or the amount of the expense limit in place at the time the amount being recouped was originally waived if lower than the Expense Limit); 2) exceed the total Fee Waiver Reimbursement Amount; or 3) include any amounts previously reimbursed to PIMCO.

The Fund anticipates that it may invest in, or gain exposure to, other series of the Trust, series of PIMCO Funds, and series of PIMCO Equity Series (each series, an "Underlying Fund," and collectively, the "Underlying Funds"). The Fund pays a management fee directly to PIMCO at the annual rate stated above, based on the average daily net assets of the Fund. Each Investing Fund also indirectly pays its proportionate share of the advisory fees, supervisory and administrative fees and management fees charged by PIMCO to the Underlying Funds in which the Fund invests (collectively, the "Underlying PIMCO Fund Fees"). With respect to the Fund, PIMCO has contractually agreed, through October 31, 2027, to waive the management fee it receives from the Investing Fund in an amount equal to the actual amount of Underlying PIMCO Fund Fees indirectly incurred by the Fund in connection with its direct investments in Underlying Funds up to a maximum waived amount that is equal to the Fund's aggregate management fee. This waiver will automatically renew for one-year terms unless PIMCO provides written notice to the Trust at least 30 days prior to the end of the then current term. Investors should be aware that an Underlying Fund may engage in securities lending transactions, and the cash collateral received by an Underlying Fund engaging in a securities lending transaction may be invested in short-term liquid fixed income instruments or in money market or short-term funds, or similar investment vehicles, including affiliated money market or short-term funds, as further described in such Underlying Fund's registration statement. In such case, the Underlying Fund will incur investment advisory fees, supervisory and administrative fees, service fees or other fees in connection with such investment of cash collateral. Ultimately, such fees will be borne by the Fund and will not be waived under the contractual waiver described above. For the avoidance of doubt, exposure obtained by the Fund to Underlying PIMCO Funds through derivatives is not in scope for purposes of this fee waiver.

Fees Associated with Fund of Funds Structure

The Fund operates as a "fund-of-funds." The expenses associated with investing in a fund of funds are generally higher than those for funds that do not invest in other funds. The cost of investing in a fund of funds, such as the Fund, will generally be higher than the cost of investing in a fund that invests directly in individual stocks and bonds. By investing in the Fund, an investor will indirectly bear fees and expenses charged by third-party managed funds in addition to the Fund's direct fees and expenses. Similarly, the gross performance of the Fund's derivatives on PIMCO Active Fixed-Income ETFs will be reduced by the fees and expenses of such PIMCO Active Fixed-Income ETFs. In non-normal circumstances, the Fund may also invest directly in shares of underlying PIMCO funds and investors will indirectly bear fees and expenses charged by such underlying PIMCO funds. PIMCO will not waive any fees or expenses of an underlying PIMCO fund embedded in the returns of the derivatives entered into by the Fund. In addition, the use of a fund of funds structure could affect the timing, amount and character of distributions to the shareholders and may therefore increase the amount of taxes payable by shareholders.

Individual Portfolio Managers

The following individuals have or share primary responsibility for managing the Fund.

Portfolio Manager	Since	Recent Professional Experience
Jerome Schneider	*	Managing Director, PIMCO. Mr. Schneider is the leader of short-term portfolio management and funding. Morningstar named him Fixed-Income Fund Manager of the Year (U.S.) for 2015. Prior to joining PIMCO in 2008, Mr. Schneider was a senior managing director with Bear Stearns. There he most recently specialized in credit and mortgage-related funding transactions and helped develop one of the first "repo" conduit financing companies. Additionally, during his tenure at Bear Stearns he held various positions on the municipal and fixed income derivatives trading desks. Mr. Schneider has investment experience since 1995 and holds an undergraduate degree in economics and international relations from the University of Pennsylvania and an MBA from the Stern School of Business at New York University.

December 2, 2025 (as supplemented January 14, 2026) | Prospectus 23

PIMCO ETF Trust

Portfolio Manager	Since	Recent Professional Experience
Joshua Spitz	*	Mr. Spitz is an executive vice president and portfolio manager in the Newport Beach office, focusing on volatility and relative value trading strategies. Prior to joining PIMCO in 2022, he was a portfolio manager at JD Capital Management. Previously, he was a managing director and head of equities index trading at Wells Fargo. He also held prior roles heading equities index volatility trading at BNP, Barclays, and Lehman Brothers. He also taught mathematics at Bronx Outreach High School, a last-chance public high school in the South Bronx, New York City. He has 20 years of investment experience and holds an MBA from Harvard Business School and a bachelor's degree in economics from the University of California, Berkeley.
Tanuj Dora	*	Senior Vice President, PIMCO. Mr. Dora is a portfolio manager in the New York office. He heads capital markets for PIMCO's ETF business and works on efficient trading and portfolio management of PIMCO ETFs. Prior to joining PIMCO in 2021, Mr. Dora was a portfolio manager for fixed income ETFs and index mandates at DWS (formerly Deutsche Asset Management), managing over $7 billion in ETF assets. Mr. Dora joined DWS in 2016 and was responsible for launching and building out DWS's fixed income ETF business in the US. Prior to his role at DWS, he was based in London working for Deutsche Bank AG as an ETF market maker and trader. He holds B. Tech and M.Tech degrees in industrial engineering and management from Indian Institute of Technology Kharagpur.

Inception of the Fund.

Please see the SAI for additional information about other accounts managed by the portfolio managers, the portfolio managers' compensation and the portfolio managers' ownership of shares of the Fund.

The Trustees are responsible generally for overseeing the management of the Trust. The Trustees authorize the Trust to enter into service agreements with the Investment Adviser, the Distributor (as defined below), and other service providers in order to provide, and in some cases authorize service providers to procure through other parties, necessary or desirable services on behalf of the Trust and the Fund. Shareholders are not parties to or third-party beneficiaries of such service agreements. Neither this prospectus nor summary prospectus, the Trust's SAI, any contracts filed as exhibits to the Trust's registration statement, nor any other communications, disclosure documents or regulatory filings from or on behalf of the Trust or the Fund creates a contract between or among any shareholder of the Fund, on the one hand, and the Trust, the Fund, a service provider to the Trust or the Fund, and/or the Trustees or officers of the Trust, on the other hand. The Trustees (or the Trust and its officers, service providers or other delegates acting under authority of the Trustees) may amend this, or use a new prospectus, summary prospectus or SAI with respect to the Fund or the Trust, and/or amend, file and/or issue any other communications, disclosure documents or regulatory filings, and may amend or enter into any contracts to which the Trust or the Fund is a party, and interpret the investment objective(s), policies, restrictions and contractual provisions applicable to the Fund, without shareholder input or approval, except in circumstances in which shareholder approval is specifically required by law (such as changes to fundamental investment policies) or where a shareholder approval requirement is specifically disclosed in the Trust's then-current prospectus or SAI.

Distributor

The Trust's Distributor is PIMCO Investments LLC (the "Distributor"). The Distributor, located at 1633 Broadway, New York, NY 10019, is a broker-dealer registered with the SEC. The Distributor distributes Creation Units for the Fund and does not maintain a secondary market in shares of the Fund.

Distribution and Servicing Plan

The Trust has adopted a Distribution and Servicing Plan (the "12b-1 Plan") for shares of the Fund pursuant to Rule 12b-1 under the Investment Company Act of 1940, as amended (the "1940 Act"). The 12b-1 Plan permits compensation in connection with the distribution and marketing of Fund shares and/or the provision of certain shareholder services. The 12b-1 Plan permits the Fund to pay compensation at an annual rate of up to 0.25% of the Fund's average daily net assets. However, the Board of Trustees has determined not to authorize payment of a 12b-1 Plan fee at this time. The 12b-1 fee may only be imposed or increased when the Board of Trustees determines that it is in the best interests of shareholders to do so. Because these fees are paid out of the Fund's assets on an ongoing basis, to the extent that a fee is authorized, over time they will increase the cost of an investment in the Fund and therefore, the 12b-1 Plan fee may cost an investor more than other types of sales charges.

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Payments to Broker-Dealers and Other Financial Intermediaries

PIMCO or the Distributor (for purposes of this subsection only, collectively, "PIMCO") makes payments to broker-dealers or other financial intermediaries (each, an "Intermediary") related to activities that are designed to make registered representatives, other professionals and individual investors more knowledgeable about the Fund or for other activities, such as participation in marketing activities and presentations, educational training programs, the support of technology platforms and/or reporting systems. PIMCO also makes payments to Intermediaries for certain printing, publishing and mailing costs associated with the Fund or materials relating to ETFs in general. In addition, PIMCO makes payments to Intermediaries that make Fund shares available to their clients, including on no transaction fee platforms, or for otherwise promoting the sale and distribution of the Fund. Such payments, which may be significant to the Intermediary, are not made by the Fund. Rather, such payments are made by PIMCO from its own resources, which may come directly or indirectly in part from management fees paid by the Fund. Payments of this type are sometimes referred to as marketing support or revenue-sharing payments. Such payments may include the reimbursement of ticket charges and revenue sharing tied to assets under management. An Intermediary may make decisions about which investment options it recommends or makes available, or the level of services provided, to its customers based on the marketing support payments it is eligible to receive. Therefore, such payments to an Intermediary create conflicts of interest between the Intermediary and its customers and may cause the Intermediary to recommend the Fund over another investment. More information regarding these payments is contained in the SAI. A shareholder should contact his or her Intermediary's salesperson or other investment professional for more information regarding any such payments the Intermediary firm may receive from PIMCO.

Buying and Selling Shares

Shares of the Fund are listed for trading on a national securities exchange during the trading day. The Fund's primary listing exchange is Cboe. Shares can be bought and sold throughout the trading day like shares of other publicly traded companies. However, there can be no guarantee that an active trading market will develop or be maintained, or that the Fund shares listing will continue or remain unchanged. The Trust does not impose any minimum investment for shares of the Fund purchased on an exchange. Buying or selling the Fund's shares involves certain costs that apply to all securities transactions. When buying or selling shares of the Fund through a financial intermediary, you may incur a brokerage commission or other charges determined by your financial intermediary. Due to these brokerage costs, if any, frequent trading may detract significantly from investment returns. In addition, you may also incur the cost of the spread (the difference between the bid price and the ask price). The commission is frequently a fixed amount and may be a significant cost for investors seeking to buy or sell small amounts of shares. The spread varies over time for shares of the Fund based on its trading volume and market liquidity, and is generally less if the Fund has more trading volume and market liquidity and more if the Fund has less trading volume and market liquidity.

Shares of the Fund may be acquired through the Distributor or redeemed directly with the Fund only in Creation Units or multiples thereof, as discussed in the "Creations and Redemptions" section of the SAI. Once created, shares of the Fund generally trade in the secondary market in amounts less than a Creation Unit.

The Trust's Board of Trustees has not adopted a policy of monitoring for frequent purchases and redemptions of Fund shares ("frequent trading") that appear to attempt to take advantage of potential arbitrage opportunities presented by a lag between a change in the value of the Fund's portfolio securities after the close of the primary markets for the Fund's portfolio securities and the reflection of that change in the Fund's NAV ("market timing"). The Trust believes this is appropriate because an ETF, such as the Fund, is intended to be attractive to arbitrageurs, as trading activity is critical to ensuring that the market price of Fund shares remains at or close to NAV. Since the Fund issues and redeems Creation Units at NAV plus applicable transaction fees, and the Fund's shares may be purchased and sold on Cboe at prevailing market prices, the risks of frequent trading are limited.

The New York Stock Exchange ("NYSE") is open for trading Monday through Friday and is closed on the following holidays: New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Good Friday, Memorial Day, Juneteenth National Independence Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day.

A "Business Day" with respect to the Fund is each day NYSE is open. Orders from Authorized Participants to create or redeem Creation Units will only be accepted on a Business Day. On days when NYSE closes earlier than normal, the Fund may require orders to create or redeem Creation Units to be placed earlier in the day. See the SAI for more information.

Section 12(d)(1) of the 1940 Act restricts investments by registered investment companies and companies relying on Sections 3(c)(1) or 3(c)(7) of the 1940 Act in the securities of other investment companies. Because the Fund may invest a substantial portion of its assets in underlying funds, other registered investment companies may not be permitted to invest in the Fund beyond the limits set forth in Section 12(d)(1), unless an exemption is available.

The Trust typically does not offer or sell its shares to non-U.S. resident Authorized Participants. For purposes of this policy, a U.S. resident Authorized Participant is defined as an Authorized Participant that has a U.S. address of record at the time of sale.

December 2, 2025 (as supplemented January 14, 2026) | Prospectus 25

PIMCO ETF Trust

Book Entry

Shares of the Fund are held in book-entry form, which means that no stock certificates are issued. The Depository Trust Company ("DTC") or its nominee is the record owner of all outstanding shares of the Fund and is recognized as the owner of all shares for all purposes.

Investors owning shares of the Fund are beneficial owners as shown on the records of DTC or its participants. DTC serves as the securities depository for shares of the Fund. DTC participants include securities brokers and dealers, banks, trust companies, clearing corporations and other institutions that directly or indirectly maintain a custodial relationship with DTC. As a beneficial owner of shares, you are not entitled to receive physical delivery of stock certificates or to have shares registered in your name, and you are not considered a registered owner of shares. Therefore, to exercise any right as an owner of shares, you must rely upon the procedures of DTC and its participants. These procedures are the same as those that apply to any other exchange-traded securities that you hold in book-entry or "street name" form.

Share Prices

The trading prices of the Fund's shares in the secondary market generally differ from the Fund's daily NAV per share and are affected by market forces such as supply and demand, economic conditions and other factors. Information regarding the intraday indicative value ("IIV") of the Fund may be disseminated every 15 seconds throughout the trading day by the national securities exchange on which the Fund's shares are primarily listed or by market data vendors or other information providers. The IIV is based on the current market value of the securities and/or cash included in the Fund's IIV basket. The IIV does not necessarily reflect the precise composition of the current portfolio of securities and instruments held by the Fund at a particular point in time or the best possible valuation of the current portfolio. Unlike the Fund's NAV, the IIV may not reflect estimated accrued interest, dividends and other income, or Fund expenses. Therefore, the IIV should not be viewed as a "real-time" update of the NAV, which is computed only once a day. The IIV is generally determined by using both current market quotations and/or price quotations obtained from broker-dealers that may trade in the portfolio securities and instruments included in the Fund's IIV basket. The Fund is not involved in, or responsible for, the calculation or dissemination of the IIV and makes no representation or warranty as to its accuracy. An inaccuracy in the IIV could result from various factors, including the difficulty of pricing portfolio instruments on an intraday basis.

Premiums and Discounts

There may be differences between the daily market prices on secondary markets for shares of the Fund and the Fund's NAV. NAV is the price per share at which the Fund issues and redeems shares. See "How Net Asset Value Is Determined" below. The Fund's market price may be at, above or below its NAV. The NAV of the Fund will fluctuate with changes in the market value of its portfolio holdings. The market price of the Fund will fluctuate in accordance with changes in its NAV, as well as market supply and demand. Information regarding the Fund's NAV and market price can be found at https://www.pimco.com/en-us/investments/etf.

Premiums or discounts are the differences (expressed as a percentage) between the NAV and the market price of the Fund on a given day, generally at the time the NAV is calculated. A premium is the amount that the Fund is trading above the reported NAV, expressed as a percentage of the NAV. A discount is the amount that the Fund is trading below the reported NAV, expressed as a percentage of the NAV. A discount or premium could be significant. Information regarding the frequency of daily premiums or discounts, generally at the time the NAV is calculated, can be found at www.pimcoetfs.com.

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Request for Multiple Copies of Shareholder Documents

To reduce expenses, it is intended that only one copy of the Fund's prospectus and annual and semi-annual reports to shareholders, when available, will be mailed to those addresses shared by two or more accounts. If you wish to receive individual copies of these documents, please contact the financial intermediary through which you hold your shares.

Information Regarding State Escheatment Laws

Fund accounts can be considered abandoned property. States increasingly are looking at inactive accounts as possible abandoned or unclaimed property. Under certain circumstances, the Fund (or the broker or custodian of record having beneficial owner information) may be legally obligated to escheat (or transfer) an investor's account to the appropriate state's unclaimed property administrator. The Fund will not be liable to investors or their representatives for good faith compliance with state unclaimed or abandoned property (escheatment) laws.

Escheatment laws vary by state, and states have different criteria for defining inactivity and abandoned property. Generally, a fund account may be subject to "escheatment" (i.e., considered to be abandoned or unclaimed property) if the account owner has not initiated any activity in the account or contacted the fund for an "inactivity period" as specified in applicable state laws. Typically, an investor's last known address of record determines the state that has jurisdiction.

The process described above, and the application of state escheatment laws, may vary depending on how shareholders hold their shares in the Fund.

How Net Asset Value Is Determined

The NAV of the Fund is determined by dividing the total value of the Fund's portfolio investments and other assets attributable to that Fund, less any liabilities, by the total number of shares outstanding of that Fund.

On each day that the NYSE is open, Fund shares are ordinarily valued as of the close of regular trading ("NYSE Close"). Information that becomes known to the Fund or its agents after the time as of which NAV has been calculated on a particular day will not generally be used to retroactively adjust the price of a security or the NAV determined earlier that day. If regular trading on the NYSE closes earlier than scheduled, the Fund reserves the right to either (i) calculate its NAV as of the earlier closing time or (ii) calculate its NAV as of the normally scheduled close of regular trading on the NYSE for that day. The Fund generally does not calculate its NAV on days during which the NYSE is closed. However, if the NYSE is closed on a day it would normally be open for business, the Fund reserves the right to calculate its NAV as of the normally scheduled close of regular trading on the NYSE for that day or such other time that the Fund may determine.

For purposes of calculating NAV, portfolio securities and other assets for which market quotations are readily available are valued at market value. A market quotation is readily available only when that quotation is a quoted price (unadjusted) in active markets for identical investments

that the Fund can access at the measurement date, provided that a quotation will not be readily available if it is not reliable. Market value is generally determined on the basis of official closing prices or the last reported sales prices. The Fund will normally use pricing data for domestic equity securities received shortly after the NYSE Close and do not normally take into account trading, clearances or settlements that take place after the NYSE Close. A foreign (non-U.S.) equity security traded on a foreign exchange or on more than one exchange is typically valued using pricing information from the exchange considered by PIMCO to be the primary exchange. If market value pricing is used, a foreign (non-U.S.) equity security will be valued as of the close of trading on the foreign exchange, or the NYSE Close, if the NYSE Close occurs before the end of trading on the foreign exchange.

Investments for which market quotations are not readily available are valued at fair value as determined in good faith pursuant to Rule 2a-5 under the 1940 Act. As a general principle, the fair value of a security or asset is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Pursuant to Rule 2a-5, the Board of Trustees has designated PIMCO as the valuation designee ("Valuation Designee") for the Fund to perform the fair value determination relating to all Fund investments. PIMCO may carry out its designated responsibilities as Valuation Designee through various teams and committees. The Valuation Designee's policies and procedures govern the Valuation Designee's selection and application of methodologies for determining and calculating the fair value of Fund investments. The Valuation Designee may value Fund portfolio securities for which market quotations are not readily available and other Fund assets utilizing inputs from pricing services, quotation reporting systems, valuation agents and other third-party sources (together, "Pricing Sources").

Domestic and foreign (non-U.S.) fixed income securities, non-exchange-traded derivatives, and equity options are normally valued on the basis of quotes obtained from brokers and dealers or Pricing Sources using data reflecting the earlier closing of the principal markets for those securities. Prices obtained from Pricing Sources may be based on, among other things, information provided by market makers or estimates of market values obtained from yield data relating to investments or securities with similar characteristics. Certain fixed income securities purchased on a delayed-delivery basis are marked to market daily until settlement at the forward settlement date. Exchange-traded options, except equity options, futures and options on futures are valued at the settlement price determined by the relevant exchange. Swap agreements are valued on the basis of bid quotes obtained from brokers and dealers or market-based prices supplied by Pricing Sources. With respect to any portion of the Fund's assets that are invested in one or more open-end management investment companies (other than ETFs), the Fund's NAV will be calculated based upon the NAVs of such investments.

If a foreign (non-U.S.) equity security's value has materially changed after the close of the security's primary exchange or principal market but before the NYSE Close, the security may be valued at fair value. Foreign (non-U.S.) equity securities that do not trade when the NYSE is open are

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also valued at fair value. With respect to foreign (non-U.S.) equity securities, the Fund may determine the fair value of investments based on information provided by Pricing Sources and other third-party vendors, which may recommend fair value or adjustments with reference to other securities, indexes or assets. In considering whether fair valuation is required and in determining fair values, the Valuation Designee may, among other things, consider significant events (which may be considered to include changes in the value of U.S. securities or securities indexes) that occur after the close of the relevant market and before the NYSE Close. The Fund may utilize modeling tools provided by third-party vendors to determine fair values of non-U.S. securities. For these purposes, unless otherwise determined by the Valuation Designee, any movement in the applicable reference index or instrument ("zero trigger") between the earlier close of the applicable foreign market and the NYSE Close may be deemed to be a significant event, prompting the application of the pricing model (effectively resulting in daily fair valuations). Foreign (non-U.S.) exchanges may permit trading in foreign (non-U.S.) equity securities on days when the Trust is not open for business, which may result in the Fund's portfolio investments being affected when you are unable to buy or sell shares.

Senior secured floating rate loans will generally be valued at the mean of bid/ask prices in the market for such loans, as provided by a Pricing Service. Senior secured floating rate loans for which vendor prices are not available, will be valued at fair value, which is intended to approximate market value. In valuing a senior secured floating rate loan at fair value, the factors considered may include, but are not limited to, the following: (a) the creditworthiness of the borrower and any intermediate participants, (b) the terms of the loan, (c) recent prices in the market for similar loans, if any, and (d) recent prices in the market for instruments of similar quality, rate, period until next interest rate reset and maturity.

Investments valued in currencies other than the U.S. dollar are converted to the U.S. dollar using exchange rates obtained from Pricing Sources. As a result, the value of such investments, and in turn, the NAV of the Fund's shares may be affected by changes in the value of currencies in relation to the U.S. dollar. The value of investments traded in markets outside the United States or denominated in currencies other than the U.S. dollar may be affected significantly on a day that the Trust is not open for business. As a result, to the extent that the Fund holds foreign (non-U.S.) investments, the value of those investments may change at times when shareholders are unable to buy or sell shares and the value of such investments will be reflected in the Fund's next calculated NAV.

Fair valuation may require subjective determinations about the value of a security. While the Trust's and Valuation Designee's policies and procedures are intended to result in a calculation of the Fund's NAV that fairly reflects security values as of the time of pricing, the Trust cannot ensure that fair values accurately reflect the price that the Fund could obtain for a security if it were to dispose of that security as of the time of pricing (for instance, in a forced or distressed sale). The prices used by the Fund may differ from the value that would be realized if the securities were sold.

Fund Distributions

The Fund distributes substantially all of its net investment income to shareholders in the form of dividends. The Fund intends to declare and distribute income dividends quarterly to shareholders of record. The Fund's first distribution to shareholders may, but is not required to, occur after its full quarter of operations. In addition, the Fund distributes any net capital gains earned from the sale of portfolio securities to shareholders no less frequently than annually. Net short-term capital gains may be paid more frequently. Dividend payments are made through DTC participants and indirect participants to beneficial owners then of record with proceeds received from the Fund. No dividend reinvestment service is provided by the Trust. Financial intermediaries may make available the DTC book-entry Dividend Reinvestment Service for use by beneficial owners of Fund shares for reinvestment of their dividend distributions. Beneficial owners should contact their financial intermediary to determine the availability and costs of the service and the details of participation therein. Financial intermediaries may require beneficial owners to adhere to specific procedures and timetables. If this service is available and used, dividend distributions of both income and net capital gains will be automatically reinvested in additional whole shares of the Fund purchased in the secondary market.

Tax Consequences

The following information is meant as a general summary for U.S. taxpayers. Please see the SAI for additional information. You should rely on your own tax adviser for advice about the particular federal, state and local tax consequences to you of investing in the Fund.

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Taxes on Fund Distributions. If you are subject to U.S. federal income tax you will be subject to tax on taxable Fund distributions. For federal income tax purposes, taxable Fund distributions will be taxable to you as either ordinary income or capital gains.

Fund taxable dividends (i.e., distributions of investment income) are generally taxable to you as ordinary income. Federal taxes on Fund distributions of gains are determined by how long the Fund owned the investments that generated the gains, rather than how long you have owned your shares. Distributions of gains from investments that the Fund owned for more than one year will generally be taxable to you as long-term capital gains. Distributions of gains from investments that the Fund owned for one year or less will generally be taxable to you as ordinary income.

The tax treatment of income, gains and losses attributable to foreign currencies (and derivatives on such currencies), and various other special tax rules applicable to certain financial transactions and instruments could affect the amount, timing and character of the Fund's distributions. In some cases, these tax rules could also result in a retroactive change in the tax character of prior distributions and may also possibly cause all, or a portion, of prior distributions to be reclassified as returns of capital for tax purposes. See "Returns of Capital" below.

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Taxable Fund distributions are taxable to you even if they are paid from income or gains earned by the Fund prior to your investment and thus were included in the price you paid for your shares. For example, if you purchase shares on or before the record date of the Fund distribution, you will pay full price for the shares and may receive a portion of your investment back as a taxable distribution.

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Taxes When You Sell Your Shares. Any gain resulting from the sale of Fund shares will generally be subject to federal income tax. Currently, any capital gain or loss realized upon a sale of Fund shares is generally treated as a long-term gain or loss if the shares have been held for more than one year. Any capital gain or loss realized upon a sale of Fund shares held for one year or less is generally treated as short-term gain or loss, except that any capital loss on the sale of shares held for six months or less is treated as long-term capital loss to the extent that capital gain dividends were paid with respect to such shares.

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Taxes on Creations and Redemptions of Creation Units. A person who exchanges securities for Creation Units generally will recognize a gain or loss. The gain or loss will be equal to the difference between the market value of the Creation Units at the time of exchange and the sum of the exchanger's aggregate basis in the securities surrendered and the amount of any cash paid for such Creation Units. A person who exchanges Creation Units for securities will generally recognize a gain or loss equal to the difference between the exchanger's basis in the Creation Units and the sum of the aggregate market value of the securities received. The Internal Revenue Service ("IRS"), however, may assert that a loss realized upon an exchange of primarily securities for Creation Units cannot be deducted currently under the rules governing "wash sales," or on the basis that there has been no significant change in economic position. Persons exchanging securities for Creation Units or redeeming Creation Units should consult their own tax adviser with respect to whether wash sale rules apply and when a loss might be deductible and the tax treatment of any creation or redemption transaction. Under current U.S. federal income tax laws, any capital gain or loss realized upon a redemption (or creation) of Creation Units is generally treated as long-term capital gain or loss if the shares (or securities surrendered) have been held for more than one year and as a short-term capital gain or loss if the shares (or securities surrendered) have been held for one year or less.

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Returns of Capital. If the Fund's distributions exceed its taxable income and capital gains realized during a taxable year, all or a portion of the distributions made in the same taxable year may be recharacterized as a return of capital to shareholders. A return of capital distribution will generally not be taxable, but will reduce each shareholder's cost basis in the Fund and result in a higher reported capital gain or lower reported capital loss when those shares on which the distribution was received are sold.

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Medicare Tax. An additional 3.8% Medicare tax is imposed on certain net investment income (including ordinary dividends and capital gain distributions received from the Fund and net gains

from redemptions or other taxable dispositions of Fund shares) of U.S. individuals, estates and trusts to the extent that such person's "modified adjusted gross income" (in the case of an individual) or "adjusted gross income" (in the case of an estate or trust) exceeds certain threshold amounts.

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Important Tax Reporting Considerations. The Internal Revenue Code of 1986 requires reporting of adjusted cost basis information for covered securities, which generally include shares of a regulated investment company acquired after January 1, 2012, to the IRS. Shareholders should contact their financial intermediaries with respect to reporting of cost basis and available elections for their accounts.

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Backup Withholding. Shareholders may be subject to U.S. federal income tax withholding with respect to distributions payable to shareholders if they fail to provide their correct taxpayer identification number or to make required certifications, or if they have been notified by the IRS that they are subject to backup withholding. Backup withholding is not an additional tax. Any amounts withheld may be credited against U.S. federal income tax liability.

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Foreign Withholding Taxes. The Fund may be subject to foreign withholding or other foreign taxes, which in some cases can be significant on any income or gain from investments in foreign securities. In that case, the Fund's total return on those securities would be decreased. Athough in some cases the Fund may be able to apply for a refund of a portion of such taxes, the ability to successfully obtain such a refund may be uncertain. The Fund may generally deduct these taxes in computing its taxable income. Rather than deducting these foreign taxes if more than 50% of the value of the Fund's total assets at the close of its taxable year consists of stock or securities of foreign corporations or foreign governments, or if at least 50% of the value of the Fund's total assets at the close of each quarter of its taxable year is represented by interests in other regulated investment companies, the Fund may make an election to treat a proportionate amount of eligible foreign taxes as constituting a taxable distribution to each shareholder, which would, subject to certain limitations, generally allow the shareholder to either (i) credit that proportionate amount of taxes against U.S. Federal income tax liability as a foreign tax credit or (ii) take that amount as an itemized deduction.

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A Note on the Fund of Funds Structure. The Fund's use of a fund of funds structure could affect the amount, timing and character of distributions to shareholders, and may therefore increase the amount of taxes payable by shareholders.

Foreign shareholders may be subject to U.S. tax withholding of 30% (or lower applicable treaty rate) on distributions from the Fund. Additionally, the Fund is required to withhold U.S. tax (at a 30% rate) on payments of taxable dividends made to certain non-U.S. entities that fail to comply (or are deemed noncompliant) with extensive reporting and withholding requirements designed to inform the U.S. Department

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of the Treasury of U.S.-owned foreign investment accounts. Shareholders may be requested to provide additional information to enable the Fund to determine whether withholding is required.

This "Tax Consequences" section relates only to federal income tax; the consequences under other tax laws may differ. Shareholders should consult their tax advisors as to the possible application of foreign, state and local income tax laws to Fund dividends and capital distributions. Please see "Taxation" in the SAI for additional information regarding the tax aspects of investing in the Fund.

Characteristics and Risks of Securities and Investment Techniques

This section provides additional information about some of the principal investments and related risks of the Fund and of certain PIMCO Active Fixed-Income ETFs and third-party managed funds described under "Fund Summary" and "Description of Principal Risks" above. It also describes characteristics and risks of additional securities and investment techniques that may be used by the PIMCO Active Fixed-Income ETFs and third-party managed funds from time to time. Generally, the characteristics and risks of securities and investment techniques that may be used by the PIMCO Active Fixed-Income ETFs and third-party managed funds from time to time are similar to those described below. However, the risks associated with a PIMCO Active Fixed-Income ETF and third-party managed fund investments are described more fully in each PIMCO Active Fixed-Income ETF's or third-party managed fund's prospectus. Accordingly, please see a PIMCO Active Fixed-Income ETF or third-party managed fund prospectus for a more complete description of the PIMCO Active Fixed-Income ETF or third-party managed fund and the risks associated with its investments.

Most of these securities and investment techniques described herein are discretionary, which means that PIMCO can decide whether to use them or not. This prospectus does not attempt to disclose all of the various types of securities and investment techniques that may be used by the Fund. As with any fund, investors in the Fund rely on the professional investment judgment and skill of PIMCO and the individual portfolio managers. Please see "Investment Objectives and Policies" in the SAI for more detailed information about the securities and investment techniques described in this section and about other strategies and techniques that may be used by the Fund.

The Fund may invest in, or enter into derivatives on, shares of underlying funds. The risks of investing in the Fund may be closely related to the risks associated with these underlying funds and their investments. However, as the Fund may also invest its assets directly in Fixed Income Instruments, equity securities, forwards or derivatives, such as options, futures contracts or swap agreements, other affiliated or unaffiliated funds, and other investments, the Fund may be directly exposed to certain risks described below.

Investors should be aware that the investments made by the Fund and the results achieved by the Fund at any given time, including for the same or similar investments, are not expected to be the same as those made by other funds for which PIMCO acts as investment adviser,

including funds with names, investment objectives and policies, and/or portfolio management teams, similar to the Fund. This may be attributable to a wide variety of factors, including, but not limited to, the use of a different strategy or portfolio management team, the execution venue(s) used for a given strategy or Fund when a particular fund commenced operations or the size of a particular fund, in each case as compared to other similar funds.

Significant purchases and redemptions of its Creation Units for cash could be driven by a variety of circumstances, such as changing market and economic conditions, and asset allocations or other decisions by PIMCO. Such transactions may adversely impact the Fund's portfolio management. For example, the Fund may be forced to sell a comparatively large portion of its portfolio to meet significant Creation Unit redemptions for cash, or hold a comparatively large portion of its portfolio in cash due to significant Creation Unit purchases for cash, in each case when the Fund otherwise would not seek to do so. These transactions may cause the Fund to make investment decisions at inopportune times or prices or miss attractive investment opportunities. Such transactions may also increase the Fund's transaction costs, accelerate the realization of taxable income if such sales of investments resulted in gains and the Fund redeems Creation Units for cash, cause the Fund to make taxable distributions to its non-redeeming shareholders to a greater extent than the Fund otherwise would have, or otherwise cause the Fund to perform differently than intended. Similarly, significant purchases of its Creation Units for cash may adversely affect the Fund's performance to the extent the Fund is delayed in investing new cash and, as a result, holds a proportionally larger cash position than under ordinary circumstances and such impact may be heightened in funds of funds. While such risks may apply to Fund of any size, these risks are heightened in Fund with fewer assets under management. In addition, new Fund may not be able to fully implement their investment strategy immediately upon commencing investment operations, which could reduce investment performance.

More generally, the Fund may be adversely affected when a large shareholder purchases or redeems large amounts of shares for cash, which can occur at any time in PIMCO's discretion and may impact the Fund in the same manner as a high volume of purchase or redemption requests for cash. These large shareholders include, but are not limited to, other funds, institutional investors, and asset allocators who make investment decisions on behalf of underlying clients. Large shareholder transactions may cause the Fund to make investment decisions at inopportune times or prices or miss attractive investment opportunities. In addition, such transactions may also cause the Fund to sell certain assets in order to meet purchase or redemption requests for cash, which could indirectly affect the liquidity of the Fund's portfolio. Such transactions may also increase the Fund's transaction costs, decrease economies of scale, accelerate the realization of taxable income, or otherwise cause the Fund to perform differently than intended. While large shareholder transactions may be more frequent under certain circumstances, the Fund is generally subject to the risk that a large shareholder can purchase or redeem a significant percentage of Fund shares for cash at any time in PIMCO's discretion. Moreover, the Fund is

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subject to the risk that other shareholders may make investment decisions based on the choices of a large shareholder, which could exacerbate any potential negative effects experienced by the Fund.

Investment Selection

In selecting securities for the Fund, PIMCO develops an outlook for interest rates, currency exchange rates and the economy, analyzes credit and call risks, and uses other security selection techniques. The proportion of the Fund's assets committed to investment in securities with particular characteristics (such as quality, sector, interest rate or maturity) varies based on PIMCO's outlook for the U.S. economy and the economies of other countries in the world, the financial markets and other factors. In selecting investments for the Fund, PIMCO may use proprietary quantitative models that are developed and maintained by PIMCO, and which are subject to change over time without notice in PIMCO's discretion. The proprietary quantitative models used by PIMCO may not adequately take into account certain factors, may contain design flaws or faulty assumptions, and may rely on incomplete or inaccurate data inputs, any of which may result in a decline in the value of an investment in the Fund. There is no guarantee that PIMCO's use of a proprietary quantitative model will produce the desired result. The proprietary quantitative models used by PIMCO may not adequately take into account certain factors, may contain design flaws or faulty assumptions, and may rely on incomplete or inaccurate data inputs, any of which may result in a decline in the value of an investment in the Fund. There is no guarantee that PIMCO's use of a proprietary quantitative model will produce the desired result.

With respect to fixed income investing, PIMCO attempts to identify areas of the bond market that are undervalued relative to the rest of the market. PIMCO identifies these areas by grouping Fixed Income Instruments into sectors such as money markets, governments, corporates, mortgages, asset-backed and international. In seeking to identify undervalued currencies, PIMCO may consider many factors, including but not limited to longer-term analysis of relative interest rates, inflation rates, real exchange rates, purchasing power parity, trade account balances and current account balances, as well as other factors that influence exchange rates such as flows, market technical trends and government policies. Sophisticated proprietary software then assists in evaluating sectors and pricing specific investments. Once investment opportunities are identified, PIMCO will shift assets among sectors depending upon changes in relative valuations, credit spreads and other factors. There is no guarantee that PIMCO's investment selection techniques will produce the desired results.

Fixed Income Instruments

"Fixed Income Instruments," as used generally in this prospectus, includes:

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securities issued or guaranteed by the U.S. Government, its agencies or government-sponsored enterprises ("U.S. Government Securities");

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corporate debt securities of U.S. and non-U.S. issuers, including convertible securities and corporate commercial paper;

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mortgage-backed and other asset-backed securities;

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inflation-indexed bonds issued both by governments and corporations;

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structured notes, including hybrid or "indexed" securities and event-linked bonds;

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bank capital and trust preferred securities;

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loans, including participations in and assignments thereof;

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delayed funding loans and revolving credit facilities;

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bank certificates of deposit, fixed time deposits and bankers' acceptances;

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repurchase agreements on Fixed Income Instruments and reverse repurchase agreements on Fixed Income Instruments;

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debt securities issued by states or local governments and their agencies, authorities and other government-sponsored enterprises;

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obligations of non-U.S. governments or their subdivisions, agencies and government-sponsored enterprises; and

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obligations of international agencies or supranational entities.

Securities issued by U.S. Government agencies or government- sponsored enterprises may not be guaranteed by the U.S. Treasury.

The Fund, to the extent permitted by the 1940 Act, the rules thereunder or any exemptive relief therefrom, may invest in derivatives based on Fixed Income Instruments.

Duration

Duration is a measure used to determine the sensitivity of a security's price to changes in interest rates that incorporates a security's yield, coupon, final maturity and call features, among other characteristics. The longer a security's duration, the more sensitive it will be to changes in interest rates. Similarly, a fund with a longer average portfolio duration will be more sensitive to changes in interest rates than a fund with a shorter average portfolio duration. By way of example, the price of a bond fund with an average duration of eight years would be expected to fall approximately 8% if interest rates rose by one percentage point. Conversely, the price of a bond fund with an average duration of negative three years would be expected to rise approximately 3% if interest rates rose by one percentage point. The maturity of a security, another commonly used measure of price sensitivity, measures only the time until final payment is due, whereas duration takes into account the pattern of all payments of interest and principal on a security over time, including how these payments are affected by prepayments and by changes in interest rates, as well as the time until an interest rate is reset (in the case of variable-rate securities). PIMCO uses an internal model for calculating duration, which may result in a different value for the duration of an index compared to the duration calculated by the index provider or another third party.

U.S. Government Securities

U.S. Government Securities are obligations of, or guaranteed by, the U.S. Government, its agencies or government-sponsored enterprises. The U.S. Government does not guarantee the NAV of the Fund's shares. U.S. Government Securities are subject to market and interest rate risk,

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as well as varying degrees of credit risk. Some U.S. Government Securities are issued or guaranteed by the U.S. Treasury and are supported by the full faith and credit of the United States. Other types of U.S. Government Securities are supported by the full faith and credit of the United States (but not issued by the U.S. Treasury). These securities may have less credit risk than U.S. Government Securities not supported by the full faith and credit of the United States. Such other types of U.S. Government Securities are: (1) supported by the ability of the issuer to borrow from the U.S. Treasury; (2) supported only by the credit of the issuing agency, instrumentality or government-sponsored corporation; or (3) supported by the United States in some other way. These securities may be subject to greater credit risk. U.S. Government Securities include zero coupon securities, which do not distribute interest on a current basis and tend to be subject to greater market risk than interest-paying securities of similar maturities. The U.S. Government Securities in which the Fund may invest may pay fixed, floating, variable or adjustable interest rates.

Securities issued by U.S. Government agencies or government-sponsored enterprises may not be guaranteed by the U.S. Treasury. Government National Mortgage Association ("GNMA"), a wholly-owned U.S. Government corporation, is authorized to guarantee, with the full faith and credit of the U.S. Government, the timely payment of principal and interest on securities issued by institutions approved by GNMA and backed by pools of mortgages insured by the Federal Housing Administration or guaranteed by the Department of Veterans Affairs. Government-related guarantors (i.e., not backed by the full faith and credit of the U.S. Government) include the Federal National Mortgage Association ("FNMA") and the Federal Home Loan Mortgage Corporation ("FHLMC"). Pass-through securities issued by FNMA are guaranteed as to timely payment of principal and interest by FNMA but are not backed by the full faith and credit of the U.S. Government. FHLMC guarantees the timely payment of interest and ultimate collection of principal, but its participation certificates are not backed by the full faith and credit of the U.S. Government.

Municipal Bonds

Municipal Bonds are generally issued by states, territories, possessions and local governments and their agencies, authorities and other instrumentalities. Municipal Bonds are subject to interest rate, credit and market risk, uncertainties related to the tax status of a Municipal Bond or the rights of investors invested in these securities. The ability of an issuer to make payments could be affected by litigation, legislation or other political events or the bankruptcy of the issuer. In addition, imbalances in supply and demand in the municipal market may result in a deterioration of liquidity and a lack of price transparency in the market. At certain times, this may affect pricing, execution and transaction costs associated with a particular trade. The secondary market for municipal bonds also tends to be less well-developed and less liquid than many other securities markets, which may adversely affect the ability of the Fund to sell its municipal bonds at attractive prices or value municipal bonds. The value of certain municipal securities, in particular general obligation debt, may also be adversely affected by rising health care costs, increasing unfunded pension

liabilities, changes in accounting standards and by the phasing out of federal programs providing financial support. Lower-rated Municipal Bonds are subject to greater credit and market risk than higher-quality Municipal Bonds. Municipal Bonds may also have exposure to potential physical risks resulting from climate change, including extreme weather, flooding and fires. Climate risks, if they materialize, can adversely impact a municipal issuer's financial plans in current or future years including, for example, the physical impairment of a facility or other source generating revenues backing a municipal issuer's revenue bonds. As a result, the impact of climate risks could adversely impact the value of the Fund's Municipal Bond investments. The types of Municipal Bonds in which the Fund may invest include municipal lease obligations, municipal general obligation bonds, municipal essential service revenue bonds, municipal cash equivalents, loans, mortgages, pre-refunded and escrowed to maturity Municipal Bonds and other debt instruments and pools of any of the foregoing. The Fund may also invest in industrial development bonds, which are Municipal Bonds issued by a government agency on behalf of a private sector company and, in most cases, are not backed by the credit of the issuing municipality and may therefore involve more risk. The Fund may also invest in securities issued by entities whose underlying assets are Municipal Bonds.

Pre-refunded Municipal Bonds are tax-exempt bonds that have been refunded to a call date on or before the final maturity of principal and remain outstanding in the municipal market. The payment of principal and interest of the pre-refunded Municipal Bonds held by the Fund is funded from securities in a designated escrow account that holds U.S. Treasury securities or other obligations of the U.S. Government (including its agencies and instrumentalities ("Agency Securities")). As the payment of principal and interest is generated from securities held in a designated escrow account, the pledge of the municipality has been fulfilled and the original pledge of revenue by the municipality is no longer in place. The escrow account securities pledged to pay the principal and interest of the pre-refunded Municipal Bond do not guarantee the price movement of the bond before maturity. Issuers of municipal bonds refund in advance of maturity the outstanding higher cost debt and issue new, lower cost debt, placing the proceeds of the lower cost issuance into an escrow account to pre-refund the older, higher cost debt. Investment in pre-refunded Municipal Bonds held by the Fund may subject the Fund to interest rate risk, market risk and credit risk. In addition, while a secondary market exists for pre-refunded Municipal Bonds, if the Fund sells pre-refunded Municipal Bonds prior to maturity, the price received may be more or less than the original cost, depending on market conditions at the time of sale.

The Fund may invest in trust certificates issued in tender option bond programs. In these programs, a trust typically issues two classes of certificates and uses the proceeds to purchase municipal securities having relatively long maturities and bearing interest at a fixed interest rate substantially higher than prevailing short-term tax-exempt rates. There is a risk that the Fund investing in a tender option bond program will not be considered the owner of a tender option bond for federal income tax purposes, and thus will not be entitled to treat such interest as exempt from federal income tax. Certain tender option bonds may be

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illiquid or may become illiquid as a result of, among other things, a credit rating downgrade, a payment default or a disqualification from tax-exempt status.

The Fund's investment in the securities issued by a tender option bond trust may involve greater risk and volatility than an investment in a fixed rate bond, and the value of such securities may decrease significantly when market interest rates increase. Tender option bond trusts could be terminated due to market, credit or other events beyond the Fund's control, which could require the Fund to dispose of portfolio investments at inopportune times and prices. The Fund may use a tender option bond program as a way of achieving leverage in its portfolio, in which case the Fund will be subject to leverage risk. The use of tender option bonds typically will impact the Fund's duration and cause the Fund to be subject to increased duration and interest rate risk.

High Yield Securities

The Fund may invest in high yield instruments. Securities rated lower than Baa by Moody's, or equivalently rated by S&P or Fitch, are sometimes referred to as "high yield securities" or "junk bonds." Investing in these securities involves special risks in addition to the risks associated with investments in higher-rated fixed income securities. While offering a greater potential opportunity for capital appreciation and higher yields, high yield securities typically entail greater potential price volatility and may be less liquid than higher-rated securities. High yield securities may be regarded as predominantly speculative with respect to the issuer's continuing ability to meet principal and interest payments. They may also be more susceptible to real or perceived adverse economic and competitive industry conditions than higher-rated securities. The Fund may invest in securities that are in default with respect to the payment of interest or repayment of principal, or present an imminent risk of default with respect to such payments. Issuers of securities in default may fail to resume principal or interest payments, in which case the Fund may lose its entire investment.

The market values of high yield securities tend to reflect individual developments of the issuer to a greater extent than do higher-quality securities, which tend to react mainly to fluctuations in the general level of interest rates. In addition, lower-quality debt securities tend to be more sensitive to general economic conditions. Certain emerging market governments that issue high yield securities in which the Fund may invest are among the largest debtors to commercial banks, foreign governments and supranational organizations, such as the World Bank, and may not be able or willing to make principal and/or interest payments as they come due.

Mortgage-Related and Other Asset-Backed Securities

Mortgage-related securities include mortgage pass-through securities, collateralized mortgage obligations ("CMOs"), commercial mortgage-backed securities, mortgage dollar rolls, CMO residuals, stripped mortgage-backed securities ("SMBSs") and other securities that directly or indirectly represent a participation in, or are secured by and payable from, mortgage loans on real property. A to-be-announced ("TBA") transaction is a method of trading mortgage-backed securities.

In a TBA transaction, the buyer and seller agree upon general trade parameters such as issuer, maturity, coupon, face value, price and the settlement date. The actual pools delivered generally are determined two days prior to the settlement date.

The value of some mortgage-related and other asset-backed securities may be particularly sensitive to changes in prevailing interest rates. Early repayment of principal on some mortgage-related securities may expose the Fund to a lower rate of return upon reinvestment of principal. When interest rates rise, the value of a mortgage-related security generally will decline; however, when interest rates are declining, the value of mortgage-related securities with prepayment features may not increase as much as other fixed income securities. The rate of prepayments on underlying mortgages will affect the price and volatility of a mortgage-related security, and may shorten or extend the effective maturity of the security beyond what was anticipated at the time of purchase. If unanticipated rates of prepayment on underlying mortgages increase the effective maturity of a mortgage-related security, the volatility of the security can be expected to increase. See "Extension Risk" and "Prepayment Risk" below. The value of these securities may fluctuate in response to the market's perception of the creditworthiness of the issuers. Additionally, although mortgages and mortgage-related securities are generally supported by some form of government or private guarantee and/or insurance, there is no assurance that guarantors or insurers will meet their obligations.

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Extension Risk. Mortgage-related and other asset-backed securities are subject to Extension Risk, which is the risk that the issuer of such a security pays back the principal of such an obligation later than expected. This may occur when interest rates rise. This may negatively affect Fund returns, as the value of the security decreases when principal payments are made later than expected. In addition, because principal payments are made later than expected, the Fund may be prevented from investing proceeds it would otherwise have received at a given time at the higher prevailing interest rates.

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Prepayment Risk. Mortgage-related and other asset-backed securities are subject to Prepayment Risk, which is the risk that the issuer of such a security pays back the principal of such an obligation earlier than expected (due to the sale of the underlying property, refinancing, or foreclosure). This may occur when interest rates decline. Prepayment may expose the Fund to a lower rate of return upon reinvestment of principal. Also, if a security subject to prepayment has been purchased at a premium, the value of the premium would be lost in the event of prepayment.

One type of SMBS has one class receiving all of the interest from the mortgage assets (the interest-only, or "IO" class), while the other class will receive all of the principal (the principal-only, or "PO" class). The yield to maturity on an IO class is extremely sensitive to the rate of principal payments (including prepayments) on the underlying mortgage assets, and a rapid rate of principal payments may have a material

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adverse effect on the Fund's yield to maturity from these securities. The Fund may invest up to 5% of its total assets in any combination of mortgage-related or other asset-backed IO, PO or inverse floater securities.

The Fund may invest in each of collateralized bond obligations ("CBOs"), collateralized loan obligations ("CLOs"), other collateralized debt obligations ("CDOs") and other similarly structured securities. CBOs, CLOs and other CDOs are types of asset-backed securities. A CBO is a trust which is backed by a diversified pool of high-risk, below investment grade fixed income securities. A CLO is a trust typically collateralized by a pool of loans, which may include, among others, domestic and foreign senior secured loans, senior unsecured loans, and subordinate corporate loans, including loans that may be rated below investment grade or equivalent unrated loans. Other CDOs are trusts backed by other types of assets representing obligations of various parties. The Fund may invest in other asset-backed securities that have been offered to investors.

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Privately Issued Mortgage-Related Securities. Pools created by non-governmental issuers generally offer a higher rate of interest than government and government-related pools because there are no direct or indirect government or agency guarantees of payments in such pools. Privately issued mortgage-related securities are not subject to the same underwriting requirements for the underlying mortgages that are applicable to those mortgage-related securities that have a government or government-sponsored entity guarantee. As a result, the mortgage loans underlying privately issued mortgage-related securities may, and frequently do, have less favorable collateral, credit risk or other underwriting characteristics than government or government-sponsored mortgage-related securities and have wider variances in a number of terms including interest rate, term, size, purpose and borrower characteristics. The risk of nonpayment is greater for mortgage-related securities that are backed by loans that were originated under weak underwriting standards, including loans made to borrowers with limited means to make repayment. A level of risk exists for all loans, although, historically, the poorest performing loans have been those classified as subprime. Privately issued mortgage-related securities are not traded on an exchange and there may be a limited market for the securities, especially when there is a perceived weakness in the mortgage and real estate market sectors. Without an active trading market, mortgage-related securities held in the Fund's portfolio may be particularly difficult to value because of the complexities involved in assessing the value of the underlying mortgage loans.

Privately Issued Mortgage-Related Securities include securities that reflect an interest in, and are secured by, mortgage loans on commercial real property. Many of the risks of investing in commercial mortgage-backed securities reflect the risks of investing in the real estate securing the underlying mortgage loans. These risks reflect the effects of local and other economic

conditions on real estate markets, the ability of tenants to make loan payments, and the ability of a property to attract and retain tenants.

Reinvestment

The Fund may be subject to the risk that the returns of the Fund will decline during periods of falling interest rates because the Fund may have to reinvest the proceeds from matured, traded or called debt obligations at interest rates below the Fund's current earnings rate. For instance, when interest rates decline, an issuer of debt obligations may exercise an option to redeem securities prior to maturity, thereby forcing the Fund to invest in lower-yielding securities. The Fund also may choose to sell higher-yielding portfolio securities and to purchase lower-yielding securities to achieve greater portfolio diversification, because the Fund's portfolio managers believe the current holdings are overvalued or for other investment-related reasons. A decline in the returns received by the Fund from its investments is likely to have an adverse effect on the Fund's NAV, yield and total return.

Focused Investment

To the extent that the Fund focuses its investments in a particular sector, the Fund may be susceptible to loss due to adverse developments affecting that sector. These developments include, but are not limited to, governmental regulation; inflation; rising interest rates; cost increases in raw materials, fuel and other operating expenses; technological innovations that may render existing products and equipment obsolete; competition from new entrants; high research and development costs; contagion risk within a particular industry or sector; increased costs associated with compliance with environmental or other governmental regulations; and other economic, business or political developments specific to that sector. Furthermore, the Fund may invest a substantial portion of its assets in companies in related sectors that may share common characteristics, are often subject to similar business risks and regulatory burdens, and whose securities may react similarly to the types of developments described above, which will subject the Fund to greater risk. The Fund also will be subject to focused investment risk to the extent that it invests a substantial portion of its assets in a particular issuer, market, asset class, country or geographic region.

Corporate Debt Securities

Corporate debt securities are subject to the risk of the issuer's inability to meet principal and interest payments on the obligation and may also be subject to price volatility due to such factors as interest rate sensitivity, market perception of the creditworthiness of the issuer and general market liquidity. When interest rates rise, the value of corporate debt securities can be expected to decline. Debt securities with longer maturities tend to be more sensitive to interest rate movements than those with shorter maturities. In addition, certain corporate debt securities may be highly customized and as a result may be subject to, among others, liquidity and pricing transparency risks.

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Bank Capital Securities and Trust Preferred Securities

There are two common types of bank capital: Tier I and Tier II. Bank capital is generally, but not always, of investment grade quality. Tier I securities often take the form of trust preferred securities. Tier II securities are commonly thought of as hybrids of debt and preferred securities, are often perpetual (with no maturity date), callable and, under certain conditions, allow for the issuer bank to withhold payment of interest until a later date.

Trust preferred securities have the characteristics of both subordinated debt and preferred securities. The primary advantage of the structure of trust preferred securities is that they are treated by the financial institution as debt securities for tax purposes and as equity for the calculation of capital requirements. Trust preferred securities typically bear a market rate coupon comparable to interest rates available on debt of a similarly rated issuer. Typical characteristics include long-term maturities, early redemption by the issuer, periodic fixed or variable interest payments, and maturities at face value. The market value of trust preferred securities may be more volatile than those of conventional debt securities. There can be no assurance as to the liquidity of trust preferred securities and the ability of holders, such as the Fund, to sell their holdings.

Loan Participations and Assignments

The Fund may invest in fixed- and floating-rate loans, which investments generally will be in the form of loan participations and assignments of all or portions of such loans. Participations and assignments involve special types of risk, including extension risk, prepayment risk, credit risk, interest rate risk, liquidity risk, and the risks of being a lender. Loans are subject to the risk that scheduled interest or principal payments will not be made in a timely manner or at all, either of which may adversely affect the value of the loan. In addition, the collateral underlying a loan may be unavailable or insufficient to satisfy a borrower's obligation, and the Fund could become part owner of any collateral if a loan is foreclosed, subjecting the Fund to costs associated with owning and disposing of the collateral. If the Fund purchases a participation, it may only be able to enforce its rights through the lender, and may assume the credit risk of the lender in addition to the borrower.

Volatility

Volatility measures the variability in the price of an investment over time. A higher volatility level signifies an investment's value may fluctuate over a larger range within a short period of time, either up or down. A lower volatility level means an investment's value is more likely to change within a narrower range, or less frequently, over time. The more volatile the portfolio holdings of the Fund, the less predictable the returns for the Fund. Higher volatility levels may indicate heightened risk of losses. PIMCO's use of investments in seeking to manage the Fund's volatility will be consistent with the Fund's asset allocation guidelines. Although asset allocation cannot eliminate investment risk or losses, it may provide opportunities to manage the Fund's volatility relative to the Fund's target annualized volatility level.

Variable and Floating Rate Securities

Variable and floating rate securities are securities that pay interest at rates that adjust whenever a specified interest rate changes and/or that reset on predetermined dates (such as the last day of a month or a calendar quarter). In addition to senior loans, variable- and floating-rate instruments may include, without limit, instruments such as catastrophe and other event-linked bonds, bank capital securities, unsecured bank loans, corporate bonds, money market instruments and certain types of mortgage-related and other asset-backed securities. The Fund may invest in floating rate debt instruments ("floaters") and engage in credit spread trades. A credit spread trade is an investment position relating to a difference in the prices or interest rates of two bonds or other securities, in which the value of the investment position is determined by changes in the difference between the prices or interest rates as the case may be, of the respective securities. Variable and floating rate securities generally are less sensitive to interest rate changes but may decline in value if their interest rates do not rise as much, or as quickly, as interest rates in general. Conversely, floating rate securities will not generally increase in value if interest rates decline. The Fund may also invest in inverse floating rate debt instruments ("inverse floaters"). An inverse floater may exhibit greater price volatility than a fixed rate obligation of similar credit quality. The Fund may invest up to 5% of its respective total assets in any combination of mortgage-related or other asset-backed IO, PO or inverse floater securities. Additionally, the Fund may also invest, without limitation, in residual interest bonds. Residual interest bonds are a type of inverse floater. See "Municipal Bonds."

Inflation-Indexed Bonds

Inflation-indexed bonds (other than municipal inflation-indexed bonds and certain corporate inflation-indexed bonds, which are more fully described below) are fixed income securities whose principal value is periodically adjusted according to the rate of inflation. If the index measuring inflation falls, the principal value of inflation-indexed bonds (other than municipal inflation-indexed bonds and certain corporate inflation-indexed bonds) will be adjusted downward, and consequently the interest payable on these securities (calculated with respect to a smaller principal amount) will be reduced. Repayment of the original bond principal upon maturity (as adjusted for inflation) is guaranteed in the case of TIPS. For bonds that do not provide a similar guarantee, the adjusted principal value of the bond repaid at maturity may be less than the original principal.

TIPS may also be divided into individual zero-coupon instruments for each coupon or principal payment (known as "iSTRIPS"). An iSTRIP of the principal component of a TIPS issue will retain the embedded deflation floor that will allow the holder of the security to receive the greater of the original principal or inflation-adjusted principal value at maturity. iSTRIPS may be less liquid than conventional TIPS because they are a small component of the TIPS market.

Municipal inflation-indexed securities are municipal bonds that pay coupons based on a fixed rate plus the Consumer Price Index for All Urban Consumers ("CPI"). With regard to municipal inflation-indexed bonds and certain corporate inflation-indexed bonds, the inflation

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adjustment is typically reflected in the semi-annual coupon payment. As a result, the principal value of municipal inflation-indexed bonds and such corporate inflation-indexed bonds does not adjust according to the rate of inflation. At the same time, the value of municipal inflation-indexed securities and such corporate inflation-indexed securities generally will not increase if the rate of inflation decreases. Because municipal inflation-indexed securities and corporate inflation-indexed securities are a small component of the municipal bond and corporate bond markets, respectively, they may be less liquid than conventional municipal and corporate bonds.

The value of inflation-indexed bonds is expected to change in response to changes in real interest rates. Real interest rates are tied to the relationship between nominal interest rates and the rate of inflation. If nominal interest rates increase at a faster rate than inflation, real interest rates may rise, leading to a decrease in value of inflation-indexed bonds. Any increase in the principal amount of an inflation-indexed bond will be considered taxable ordinary income, even though investors do not receive their principal until maturity.

Event-Linked Exposure

The Fund may obtain event-linked exposure by investing in or gaining exposure to reinsurance contracts (through sidecars or otherwise), "event-linked bonds" or "event-linked swaps" or by implementing "event-linked strategies." Event-linked exposure results in gains or losses that typically are contingent, or formulaically related to defined trigger events. Examples of trigger events include hurricanes, earthquakes, weather-related phenomena, or statistics related to such events. Some event-linked bonds are commonly referred to as "catastrophe bonds." If a trigger event occurs, the Fund may lose a portion of or its entire principal invested in the bond or notional amount on a swap. Event-linked exposures often provide for an extension of maturity to process and audit loss claims where a trigger event has, or possibly has, occurred. An extension of maturity may increase volatility. The Fund may also have exposure to reinsurance contracts. This may include exposure to "excess of loss" contracts, wherein liability arises only if and when losses exceed a specified amount, and proportional reinsurance, wherein a portion of the premiums and liabilities of the cedant associated with a specified business or a portfolio of insurance contracts are linked to the Fund's investment. Reinsurance transactions may involve significant insurance brokerage fees, fronting fees and other transaction costs. Event-linked exposures may also expose the Fund to certain unanticipated risks including credit risk, counterparty risk, adverse regulatory or jurisdictional interpretations, and adverse tax consequences. Event-linked exposures may also be subject to liquidity risk.

Insurance-Linked and Other Instruments

The Fund may invest in insurance-linked instruments and similar investments (which may include, for example, reinsurance contracts through sidecars or otherwise, event-linked bonds, such as catastrophe and resilience bonds, and securities relating to life insurance policies, annuity contracts and premium finance loans). The Fund could lose a portion or all of the principal it has invested in these types of

investments, and the right to additional interest and/or dividend payments with respect to the investments, upon the occurrence of one or more trigger events, as defined within the terms of an investment. Trigger events may include natural or other perils of a specific size or magnitude that occur in a designated geographic region during a specified time period, and/or that involve losses or other metrics that exceed a specific amount. The Fund may also invest in insurance-linked instruments that are subject to "indemnity triggers." An indemnity trigger is a mechanism where the payout to the investor is based on the actual losses incurred by the insurer and come into play when losses from a specified event exceed a designated level. Insurance-linked instruments subject to indemnity triggers are often regarded as being subject to potential moral hazard, since such insurance-linked investments are triggered by actual losses of the ceding sponsor and the ceding sponsor may have an incentive to take actions and/or risks that would have an adverse effect on the Fund. There is no way to accurately predict whether a trigger event will occur and, accordingly, insurance-linked instruments and similar investments carry significant risk. In addition to the specified trigger events, these types of investments may expose the Fund to other risks, including but not limited to issuer (credit) default, adverse regulatory or jurisdictional interpretations and adverse tax consequences. The Fund may gain exposure to reinsurance contracts (through insurance-linked securities, sidecars or otherwise). This may include exposure to "excess of loss" contracts, wherein liability arises only if and when losses exceed a specified amount, and proportional reinsurance, wherein a portion of the premiums and liabilities of the cedant associated with a specified business or a portfolio of insurance contracts are linked to the Fund's investment. Investments linked to reinsurance transactions may involve significant insurance brokerage fees, fronting fees and other transaction costs. A series of major triggering events could cause the failure of a reinsurer. Similarly, to the extent the Fund invests in reinsurance-related securities for which a triggering event occurs, losses associated with such event will result in losses to the Fund and a series of major triggering events affecting a large portion of the reinsurance-related securities held by the Fund may result in substantial losses to the Fund. In addition, unexpected events such as natural disasters or terrorist attacks could lead to government intervention. Political, judicial and legal developments affecting the reinsurance industry could also create new and expanded theories of liability or regulatory or other requirements; such changes could have a material adverse effect on the Fund. In addition, the litigation environment in catastrophe-exposed states or regions could impact the frequency and severity of insurance claims, and litigation costs could decrease the value of the Fund's investment in products linked to reinsurance contracts. In recent years capital market participants have been increasingly active in the reinsurance market and markets for related risks. Increased competition could result in fewer submissions, lower premium rates and less favorable policy terms and conditions.

Certain insurance-linked instruments and similar investments may have limited liquidity, or may be illiquid. The Fund has limited transparency into the individual contracts underlying certain insurance-linked

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Prospectus

instruments and similar investments, which may make the risk assessment of them more difficult. These types of investments may be difficult to value.

The aforementioned instruments may include longevity and mortality investments, including indirect investment in pools of insurance-related longevity and mortality investments, including life insurance policies, annuity contracts and premium finance loans. Such investments are subject to "longevity risk" and/or "mortality risk." Longevity risk is the risk that members of a reference population will live longer, on average, than anticipated. Mortality risk is the risk that members of a reference population will live shorter, on average, than anticipated. Changes in these rates can significantly affect the liabilities and cash needs of life insurers, annuity providers and pension funds. The terms of a longevity bond typically provide that the investor in the bond will receive less than the bond's par amount at maturity if the actual average longevity (life span) of a specified population of people observed over a specified period of time (typically measured by a longevity index) is higher than a specified level. If longevity is higher than expected, the bond will return less than its par amount at maturity. A mortality bond, in contrast to a longevity bond, typically provides that the investor in the bond will receive less than the bond's par amount at maturity if the mortality rate of a specified population of people observed over a specified period of time (typically measured by a mortality index) is higher than a specified level.

During their term, both longevity bonds and mortality bonds typically pay a floating rate of interest to investors. Longevity and mortality investments purchased by the Fund involve the risk of incorrectly predicting the actual level of longevity or mortality, as applicable, for the reference population of people. With respect to mortality investments held by the Fund, there is also the risk that an epidemic or other catastrophic event could strike the reference population, resulting in mortality rates exceeding expectations. The Fund may also gain this type of exposure through event-linked derivative instruments, such as swaps, that are contingent on or formulaically related to longevity or mortality risk.

Convertible and Equity Securities

Common stock represents equity ownership in a company and typically provides the common stockholder the power to vote on certain corporate actions, including the election of the company's directors. Common stockholders participate in company profits through dividends and, in the event of bankruptcy, distributions, on a pro-rata basis after other claims are satisfied. Many factors affect the value of common stock, including earnings, earnings forecasts, corporate events and factors impacting the issuer's industry and the market generally. Common stock generally has the greatest appreciation and depreciation potential of all corporate securities.

The Fund may invest in convertible securities and equity securities, as well as securities related to equities. Equity-related securities include securities having an equity component (e.g., hybrids, bank capital) and equity derivatives.

The Fund may invest in preferred securities, convertible securities and other equity-related securities. Convertible securities are generally preferred securities and other securities, including fixed income securities and warrants, that are convertible into or exercisable for common stock at a stated price or rate. The price of a convertible security will normally vary in some proportion to changes in the price of the underlying common stock because of this conversion or exercise feature. However, the value of a convertible security may not increase or decrease as rapidly as the underlying common stock. A convertible security will normally also provide income and is subject to interest rate risk. Convertible securities may be lower-rated securities subject to greater levels of credit risk. The Fund may be forced to convert a security before it would otherwise choose, which may have an adverse effect on the Fund's ability to achieve its investment objective.

"Synthetic" convertible securities are selected based on the similarity of their economic characteristics to those of a traditional convertible security due to the combination of separate securities that possess the two principal characteristics of a traditional convertible security, i.e., an income-producing security ("income-producing component") and the right to acquire an equity security ("convertible component"). The income-producing component is achieved by investing in non-convertible, income-producing securities such as bonds, preferred securities and money market instruments, which may be represented by derivative instruments. The convertible component is achieved by investing in securities or instruments such as warrants or options to buy common stock at a certain exercise price, or options on a stock index. A simple example of a synthetic convertible security is the combination of a traditional corporate bond with a warrant to purchase equity securities of the issuer of the bond. The Fund may also purchase synthetic securities created by other parties, typically investment banks, including convertible structured notes. The income-producing and convertible components of a synthetic convertible security may be issued separately by different issuers and at different times.

Preferred and other senior securities generally entitle the holder to receive, in preference to the holders of other securities such as common stocks, dividends and a fixed share of the proceeds resulting from a liquidation of the company. Preferred and other senior securities may pay fixed or adjustable rates of return. Preferred and other senior securities are subject to issuer-specific and market risks applicable generally to equity securities. In addition, a company's preferred and other senior securities generally pay dividends only after the company makes required payments to holders of its bonds and other debt. For this reason, the value of preferred and other senior securities will usually react more strongly than bonds and other debt to actual or perceived changes in the company's financial condition or prospects. In addition, preferred and other senior securities often have special redemption rights allowing issuers to redeem such securities at par earlier than scheduled. If these rights are exercised, the Fund may have to reinvest proceeds in less attractive securities.

Among other risks described in this prospectus, the following issues are particularly associated with investments in preferred and other senior securities.

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Deferral and Omission of Distributions.Preferred and other senior securities may include features permitting or requiring the issuer to defer or omit distributions. Among other things, such deferral or omission may result in adverse tax consequences for the Fund.

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Limited Voting Rights.Preferred and other senior securities generally do not have voting rights with respect to the issuer unless dividends have been in arrears for certain specified periods of time.

In the future, preferred or other senior securities may be offered with features different from those described above, and as such, may entail different risks. Over longer periods of time, certain types of preferred or other senior securities may become more scarce or less liquid as a result of legislative changes. Such events may result in losses to the Fund as the prices of securities it holds may be negatively affected. Revisions to bank capital requirements by international regulatory bodies, to the extent they are adopted in the United States, may also negatively impact the market for certain preferred or senior securities.

While some countries or companies may be regarded as favorable investments, pure fixed income opportunities may be unattractive or limited due to insufficient supply, or legal or technical restrictions. In such cases, subject to its applicable investment restrictions, the Fund may consider convertible securities or equity securities to gain exposure to such investments. The Fund may invest in equity securities of issuers in commodity-related industries. When investing directly in equity securities, the Fund will not be limited to only those equity securities with any particular weighting in the Fund's respective benchmark index, if any. At times, in connection with the restructuring of a preferred security or Fixed Income Instrument either outside of bankruptcy court or in the context of bankruptcy court proceedings, the Fund may determine or be required to accept equity securities, such as common stocks, in exchange for all or a portion of a preferred security or Fixed Income Instrument. Depending upon, among other things, PIMCO's evaluation of the potential value of such securities in relation to the price that could be obtained by the Fund at any given time upon sale thereof, the Fund may determine to hold such securities in its portfolio. Equity securities generally have greater price volatility than fixed income securities. The market price of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably.

Equity securities may decline in value due to factors affecting equity securities markets generally or particular industries represented in those markets. The value of an equity security may also decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer's goods or services.

Preferred Securities

Preferred securities represent an equity interest in a company that generally entitles the holder to receive, in preference to the holders of other securities such as common stocks, dividends and a fixed share of the proceeds resulting from a liquidation of the company. Some preferred securities also entitle their holders to receive additional

liquidation proceeds on the same basis as holders of a company's common stock, and thus also represent an ownership interest in that company. Preferred securities may pay fixed or adjustable rates of return.

Preferred and other senior securities may pay fixed or adjustable rates of return. Preferred and other senior securities are subject to issuer-specific and market risks applicable generally to equity securities. In addition, a company's preferred and other senior securities generally pay dividends only after the company makes required payments to holders of its bonds and other debt. For this reason, the value of preferred and other senior securities will usually react more strongly than bonds and other debt to actual or perceived changes in the company's financial condition or prospects. Preferred securities of smaller companies may be more vulnerable to adverse developments than preferred securities of larger companies.

Among other risks described in this prospectus, the following issues are particularly associated with investments in preferred and other senior securities.

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Limited Voting Rights.Preferred and other senior securities generally do not have voting rights with respect to the issuer unless dividends have been in arrears for certain specified periods of time.

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Liquidity.Preferred and other senior securities may be less liquid than other securities, including common stock and U.S. government securities. As a result, these securities are subject to the risk that they may be unable to be sold at the time desired by the Fund or at prices approximating the values at which the Fund is carrying the securities on its books. In addition, over longer periods of time, certain types of preferred or other senior securities may become more scarce or less liquid as a result of legislative changes. Such events may negatively affect the prices of securities held by the Fund, which may result in losses to the Fund.

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Regulatory Changes.Revisions to bank capital requirements by international regulatory bodies, to the extent they are adopted in the United States, may also negatively impact the market for certain preferred or senior securities.

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Special Redemption Rights.An issuer of preferred or other senior securities may redeem the securities prior to a specified date, which may occur due to changes in tax or securities laws or corporate actions. A redemption by the issuer may negatively impact the return of the preferred security.

In the future, preferred or other senior securities may be offered with features different from those described above, and as such, may entail different risks.

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Over longer periods of time, certain types of preferred or other senior securities may become more scarce or less liquid as a result of legislative changes. Such events may result in losses to the Fund as the prices of securities it holds may be negatively affected. Revisions to bank capital requirements by international regulatory bodies, to the extent they are adopted in the United States, may also negatively impact the market for certain preferred or senior securities.

Contingent Convertible Securities

Contingent convertible securities ("CoCos") are a form of hybrid debt security issued primarily by non-U.S. issuers, which have loss absorption mechanisms built into their terms. CoCos have no stated maturity, have fully discretionary coupons and are typically issued in the form of subordinated debt instruments. CoCos generally either convert into equity of the issuer or have their principal written down upon the occurrence of certain triggering events ("triggers") linked to regulatory capital thresholds or regulatory actions relating to the issuer's continued viability. In certain scenarios, investors in CoCos may suffer a loss of capital ahead of equity holders or when equity holders do not. There is no guarantee that the Fund will receive a return of principal on CoCos. Any indication that an automatic write-down or conversion event may occur can be expected to have an adverse effect on the market price of CoCos. CoCos are often rated below investment grade and are subject to the risks of high yield securities.

Because CoCos are issued primarily by financial institutions, CoCos may present substantially increased risks at times of financial turmoil, which could affect financial institutions more than companies in other sectors and industries. Further, the value of an investment in CoCos is unpredictable and will be influenced by many factors and risks, including interest rate risk, credit risk, market risk and liquidity risk. An investment by the Fund in CoCos may result in losses to the Fund.

Some additional risks associated with CoCos include, but are not limited to:

Loss absorption risk. CoCos may be subject to an automatic write-down (i.e., the automatic write-down of the principal amount or value of the securities, potentially to zero, and the cancellation of the securities) under certain circumstances, which could result in the Fund losing a portion or all of its investment in such securities. In addition, the Fund may not have any rights with respect to repayment of the principal amount of the securities that has not become due or the payment of interest or dividends on such securities for any period from (and including) the interest or dividend payment date falling immediately prior to the occurrence of such automatic write-down. An automatic write-down could also result in a reduced income rate if the dividend or interest payment is based on the security's par value. In addition, CoCos have fully discretionary coupons. This means coupons can potentially be cancelled at the issuer's discretion or at the request of the relevant regulatory authority in order to help the issuer absorb losses and may be suspended in the event there are insufficient distributable reserves.

Subordinated instruments. CoCos will, in the majority of circumstances, be issued in the form of subordinated debt instruments in order to provide the appropriate regulatory capital treatment prior to

a conversion. Accordingly, in the event of liquidation, dissolution or winding-up of an issuer prior to a conversion having occurred, the rights and claims of the holders of the CoCos, such as the Fund, against the issuer in respect of or arising under the terms of the CoCos shall generally rank junior to the claims of all holders of unsubordinated obligations of the issuer. In addition, if the CoCos are converted into the issuer's underlying equity securities following a conversion event (i.e., a "trigger"), each holder will be subordinated due to their conversion from being the holder of a debt instrument to being the holder of an equity instrument.

Market value will fluctuate based on unpredictable factors. The trading behavior of a given issuer's CoCos may be strongly impacted by the trading behavior of other issuers' CoCos, such that negative information from an unrelated CoCo may cause a decline in value of one or more CoCos held by the Fund. Accordingly, the trading behavior of CoCos may not follow the trading behavior of other similarly structured securities. The value of CoCos is unpredictable and could be influenced by many factors including, without limitation: (i) the creditworthiness of the issuer and/or fluctuations in such issuer's applicable capital ratios; (ii) supply and demand for the CoCos; (iii) general market conditions and available liquidity; and (iv) economic, financial and political events that affect the issuer, its particular market or the financial markets in general.

Surplus Notes

Surplus notes are debt securities typically issued by mutual insurers that count as statutory capital under insurance regulations. Surplus notes are subordinated to policyholder claims. Coupon payments on surplus notes are contractual and typically cumulative, but each coupon and principal payment requires regulatory approval to ensure that the payment does not deplete resources available for paying policyholder claims.

Foreign (Non-U.S.) Securities

The Fund may invest in U.S. dollar-denominated securities and instruments that are economically tied to foreign (non-U.S.) countries. PIMCO generally considers an instrument to be economically tied to a non-U.S. country if the issuer is a foreign (non-U.S.) government (or any political subdivision, agency, authority or instrumentality of such government), or if the issuer is organized under the laws of a non-U.S. country. In the case of money market instruments other than commercial paper and certificates of deposit, such instruments will be considered economically tied to a non-U.S. country if the issuer of such money market instrument is organized under the laws of a non-U.S. country. In the case of commercial paper and certificates of deposit, such instruments will be considered economically tied to a non-U.S. country if the "country of exposure" of such instrument is a non-U.S. country, as determined by the criteria set forth below. With respect to derivative instruments which the Fund may utilize, PIMCO generally considers such instruments to be economically tied to non-U.S. countries if the underlying assets are foreign currencies (or baskets or indexes of such currencies), or instruments or securities that are issued by foreign governments, or issuers organized under the laws of a non-U.S. country (or if the underlying assets are money market

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instruments other than commercial paper and certificates of deposit, the issuer of such money market instrument is organized under the laws of a non-U.S. country or, in the case of underlying assets that are commercial paper or certificates of deposit, if the "country of exposure" of such money market instrument is a non-U.S. country). A security's "country of exposure" is determined by PIMCO using certain factors provided by a third-party analytical service provider. The factors are applied in order such that the first factor to result in the assignment of a country determines the "country of exposure." Both the factors and the order in which they are applied may change in the discretion of PIMCO. The current factors, listed in the order in which they are applied, are: (i) if an asset-backed or other collateralized security, the country in which the collateral backing the security is located; (ii) the "country of risk" of the issuer; (iii) if the security is guaranteed by the government of a country (or any political subdivision, agency, authority or instrumentality of such government), the country of the government or instrumentality providing the guarantee; (iv) the "country of risk" of the issuer's ultimate parent; or (v) the country where the issuer is organized or incorporated under the laws thereof. "Country of risk" is a separate four-part test determined by the following factors, listed in order of importance: (i) management location; (ii) country of primary listing; (iii) sales or revenue attributable to the country; and (iv) reporting currency of the issuer.

Investing in foreign (non-U.S.) securities involves special risks and considerations not typically associated with investing in U.S. securities. Investors should consider carefully the substantial risks involved for the Fund that invests in securities issued by foreign companies and governments of foreign countries. These risks include: differences in accounting, auditing and financial reporting standards; generally higher commission rates on foreign portfolio transactions; the possibility of the imposition of sanctions and other similar measures, nationalization, expropriation or confiscatory taxation; adverse changes in investment or exchange control regulations; market disruptions; the possibility of security suspensions; and political instability. Individual foreign (non-U.S.) economies may differ favorably or unfavorably from the U.S. economy in such respects as growth of gross domestic product, rates of inflation, capital reinvestment, resources, self-sufficiency and balance of payments position. Other countries' financial infrastructure or settlement systems may be less developed than those of the United States. The securities markets, values of securities, yields and risks associated with foreign (non-U.S.) securities markets may change independently of each other. Also, foreign (non-U.S.) securities and dividends and interest payable on those securities may be subject to foreign taxes, including taxes withheld from payments on those securities. Foreign (non-U.S.) securities often trade with less frequency and volume than domestic securities and therefore may exhibit greater price volatility. Investments in foreign (non-U.S.) securities may also involve higher custodial costs than domestic investments and additional transaction costs with respect to foreign currency conversions. Changes in, or uncertainty concerning, foreign exchange rates also will affect the value of securities denominated or quoted in foreign currencies and in some cases could lead to uncertainty regarding the reliability of issuers' financial reporting.

The Fund also may invest in sovereign debt issued by governments, their agencies or instrumentalities, or other government-related entities.

Holders of sovereign debt may be requested to participate in the rescheduling of such debt and to extend further loans to governmental entities. In addition, there is no bankruptcy proceeding by which defaulted sovereign debt may be collected.

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Emerging Market Securities. The Fund may invest in securities and instruments that are economically tied to emerging market countries. PIMCO generally considers an instrument to be economically tied to an emerging market country if: the issuer is organized under the laws of an emerging market country; the currency of settlement of the security is a currency of an emerging market country; the security is guaranteed by the government of an emerging market country (or any political subdivision, agency, authority or instrumentality of such government); for an asset-backed or other collateralized security, the country in which the collateral backing the security is located is an emerging market country; or the security's "country of exposure" is an emerging market country, as determined by the criteria set forth below. With respect to derivative instruments for the Fund, PIMCO generally considers such instruments to be economically tied to emerging market countries if the underlying assets are currencies of emerging market countries (or baskets or indexes of such currencies), or instruments or securities that are issued or guaranteed by governments of emerging market countries or by entities organized under the laws of emerging market countries or if an instrument's "country of exposure" is an emerging market country. A security's "country of exposure" is determined by PIMCO using certain factors provided by a third-party analytical service provider. The factors are applied in order such that the first factor to result in the assignment of a country determines the "country of exposure." Both the factors and the order in which they are applied may change in the discretion of PIMCO. The current factors, listed in the order in which they are applied, are: (i) if an asset-backed or other collateralized security, the country in which the collateral backing the security is located; (ii) the "country of risk" of the issuer; (iii) if the security is guaranteed by the government of a country (or any political subdivision, agency, authority or instrumentality of such government), the country of the government or instrumentality providing the guarantee; (iv) the "country of risk" of the issuer's ultimate parent; or (v) the country where the issuer is organized or incorporated under the laws thereof. "Country of risk" is a separate four-part test determined by the following factors, listed in order of importance: (i) management location; (ii) country of primary listing; (iii) sales or revenue attributable to the country; and (iv) reporting currency of the issuer. PIMCO has broad discretion to identify countries that it considers to qualify as emerging markets. In making investments in emerging market securities, the Fund emphasizes those countries with relatively low gross national product per capita and with the potential for rapid economic growth. Emerging market countries are generally located in Asia, Africa, the Middle East, Latin America and Eastern Europe. PIMCO will

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select the country and currency composition based on its evaluation of relative interest rates, inflation rates, exchange rates, monetary and fiscal policies, trade and current account balances, legal and political developments and any other specific factors it believes to be relevant.

Investing in emerging market securities imposes risks different from, or greater than, risks of investing in domestic securities or in foreign, developed countries. These risks include: smaller market capitalization of securities markets, which may suffer periods of relative illiquidity; significant price volatility; restrictions on foreign investment; possible repatriation of investment income and capital. In addition, foreign investors may be required to register the proceeds of sales; and future economic or political crises could lead to the imposition of sanctions and other similar measures, price controls, forced mergers, expropriation or confiscatory taxation, seizure, nationalization, or creation of government monopolies. The currencies of emerging market countries may experience significant declines against the U.S. dollar, and devaluation may occur subsequent to investments in these currencies by the Fund. Many emerging market countries have experienced substantial, and in some periods extremely high, rates of inflation for many years. Inflation and rapid fluctuations in inflation rates have had, and may continue to have, negative effects on the economies and securities markets of certain emerging market countries.

Additional risks of emerging market securities may include: greater social, economic and political uncertainty and instability; more substantial governmental involvement in the economy; less governmental supervision and regulation; unavailability of currency hedging techniques; companies that are newly organized and small; differences in auditing and financial reporting standards, which may result in unavailability of material information about issuers; and less developed legal systems. Emerging securities markets may have different clearance and settlement procedures, which may be unable to keep pace with the volume of securities transactions or otherwise make it difficult to engage in such transactions. Settlement problems may cause the Fund to miss attractive investment opportunities, hold a portion of its assets in cash pending investment, or be delayed in disposing of a portfolio security. Such a delay could result in possible liability to a purchaser of the security. Custody services in many emerging market countries remain undeveloped. The Fund may be investing in emerging market countries where the current law and market practice carry fewer safeguards than in more developed markets, including the protection of client securities against claims from general creditors in the event of the insolvency of an agent selected to hold securities on behalf of the Fund, and the Fund's custodian and PIMCO have assumed no liability for losses resulting from the Fund acting in accordance with such practice.

Foreign (Non-U.S.) Currencies

Direct investments in foreign (non-U.S.) currencies or in securities that trade in, or receive revenues in, foreign (non-U.S.) currencies will be subject to currency risk. Foreign currency exchange rates may fluctuate significantly over short periods of time. They generally are determined by supply and demand in the foreign exchange markets and the relative merits of investments in different countries, actual or perceived changes in interest rates and other complex factors. Currency exchange rates also can be affected unpredictably by intervention (or the failure to intervene) by U.S. or foreign (non-U.S.) governments or central banks, or by currency controls or political developments. Currencies in which the Fund's assets are denominated may be devalued against the U.S. dollar, resulting in a loss to the Fund. For purposes of calculating foreign currency exposure limits (from non-U.S. dollar denominated securities or currencies), the Fund will net long and short exposures to the same currency, and for positions involving long and short exposures to different currencies, will count the greater absolute value as between the long and short exposures (after first netting exposure within the same currency).

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Foreign Currency Transactions. The Fund may engage in foreign currency transactions on a spot (cash) basis, enter into forward foreign currency exchange contracts and invest in foreign currency futures contracts and options on foreign currencies and futures. A forward foreign currency exchange contract, which involves an obligation to purchase or sell a specific currency at a future date at a price set at the time of the contract, reduces the Fund's exposure to changes in the value of the currency it will deliver and increases its exposure to changes in the value of the currency it will receive for the duration of the contract. Certain foreign currency transactions may also be settled in cash rather than the actual delivery of the relevant currency. The effect on the value of the Fund is similar to selling securities denominated in one currency and purchasing securities denominated in another currency. Foreign currency transactions, like currency exchange rates, can be affected unpredictably by intervention (or the failure to intervene) by U.S. or foreign governments or central banks, or by currency controls or political developments. Such events may prevent or restrict the Fund's ability to enter into foreign currency transactions, force the Fund to exit a foreign currency transaction at a disadvantageous time or price or result in penalties for the Fund, any of which may result in a loss to the Fund. A contract to sell a foreign currency would limit any potential gain that might be realized if the value of the hedged currency increases. The Fund may enter into these contracts to hedge against foreign exchange risk, to increase exposure to a foreign currency or to shift exposure to foreign currency fluctuations from one currency to another. To the extent foreign exchange transactions for the Fund are directed to the Fund's custodian for execution, execution of such transactions may be better or worse than comparable transactions effected by other intermediaries. Suitable hedging transactions may not be available in all circumstances and there can be no assurance that the Fund will engage in such transactions at any given time or from time to time. Also, such

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transactions may not be successful and may eliminate any chance for the Fund to benefit from favorable fluctuations in relevant foreign currencies. The Fund may use one currency (or a basket of currencies) to hedge against adverse changes in the value of another currency (or a basket of currencies) when exchange rates between the two currencies are positively correlated.

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Redenomination. Uncertainty as to the status of the euro and the European Monetary Union (the "EMU") has at times created significant volatility in currency and financial markets generally. Any partial or complete dissolution of the EMU could have significant adverse effects on currency and financial markets and on the values of the Fund's portfolio investments. If one or more EMU countries were to stop using the euro as its primary currency, the Fund's investments in such countries may be redenominated into a different or newly adopted currency. As a result, the value of those investments could decline significantly and unpredictably. In addition, securities or other investments that are redenominated may be subject to currency risk, liquidity risk and risk of improper valuation to a greater extent than similar investments currently denominated in euros. To the extent a currency used for redenomination purposes is not specified in respect of certain EMU-related investments, or should the euro cease to be used entirely, the currency in which such investments are denominated may be unclear, making such investments particularly difficult to value or dispose of. The Fund may incur additional expenses to the extent it is required to seek judicial or other clarification of the denomination or value of such securities. There can be no assurance that if the Fund earns income or capital gains in a non-U.S. country or PIMCO otherwise seeks to withdraw the Fund's investments from a given country, capital controls imposed by such country will not prevent, or cause significant expense, or delay in, doing so.

Repurchase Agreements

The Fund may enter into repurchase agreements, in which the Fund purchases a security from a bank or broker-dealer that agrees to repurchase the security at the Fund's cost plus interest within a specified time. If the party agreeing to repurchase should default, the Fund will seek to sell the securities which it holds. This could involve procedural costs or delays in addition to a loss on the securities if their value should fall below their repurchase price. The security subject to a repurchase agreement may be or become illiquid. These events could also trigger adverse tax consequences for the Fund.

Reverse Repurchase Agreements, Dollar Rolls and Other Borrowings

The Fund may enter into reverse repurchase agreements and dollar rolls. A reverse repurchase agreement involves the sale of a security by the Fund and its agreement to repurchase the instrument at a specified time and price. A dollar roll is similar except that the counterparty is not obligated to return the same securities as those originally sold by the

Fund but only securities that are "substantially identical." Reverse repurchase agreements and dollar rolls may be considered borrowing for some purposes.

The Fund may purchase securities on margin. When purchasing securities on margin, the Fund creates an obligation to return the amount borrowed plus any interest. To purchase securities on margin, the Fund may open one or more margin accounts. A margin account is a type of account in which the Fund borrows cash to purchase securities, typically using the assets financed in this manner (and additional assets) as collateral. Margin accounts are subject to certain minimum margin requirements. If the value of the assets in the account decreases, the Fund may be required to deposit additional assets to the account or liquidate one or more investments in the account to reduce the borrowings outstanding.

Assets deposited as collateral may, subject to certain conditions, be rehypothecated by the lender up to the amount of the borrowings and subject to the terms and conditions of the borrowing agreements. The Fund continues to receive dividends and interest on rehypothecated assets. The Fund has the right to recall rehypothecated assets on demand and such assets shall be returned within the ordinary settlement cycle. In the event a recalled asset is not returned by the lender, the amount of the borrowing outstanding will be reduced by the amount of the recalled security failed to be returned. Rehypothecation of the Fund's pledged assets entails risks, including the risk that the lender will be unable or unwilling to return rehypothecated assets, which could result in, among other things, the Fund's inability to find suitable investments to replace the unreturned assets, thereby impairing the Fund's ability to achieve its investment objective. Reverse repurchase agreements, dollar rolls, margin borrowings and other forms of borrowings may create leveraging risk for the Fund.

The Fund may borrow money to the extent permitted under the 1940 Act. This means that, in general, the Fund may borrow money from banks for any purpose in an amount up to one-third of the Fund's total assets, less all liabilities and indebtedness not represented by senior securities. The Fund may also borrow money for temporary administrative purposes in an amount not to exceed 5% of the Fund's total assets. In addition, the Fund may borrow from certain other PIMCO funds in inter-fund lending transactions to the extent permitted by an exemptive order from the SEC.

Derivatives

The Fund may, but is not required to, use derivatives and other similar instruments (referred to collectively as "derivatives") for risk management purposes or as part of its investment strategies. Additionally, the Fund may invest in futures and other derivatives that provide relevant exposures, including for equitization and hedging purposes using derivatives that provide exposure that is not identical to the instruments or markets in which the Fund seeks to invest at least 80% of its assets, as applicable. Investments in derivatives may take the form of buying and/or writing (selling) derivatives. Generally, derivatives are financial contracts whose value depends upon, or is derived from, the value of an underlying asset, reference rate or index, and may relate

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to stocks, bonds, interest rates, spreads between different interest rates, currencies or currency exchange rates, commodities, and related indexes. Examples of derivative instruments include options contracts, futures contracts, options on futures contracts and swap agreements (including, but not limited to, credit default swaps and swaps on ETFs). The Fund may invest some or all of its assets in derivative instruments, subject to the Fund's objective and policies. A portfolio manager may decide not to employ any of these strategies and there is no assurance that any derivatives strategy used by the Fund will succeed. A description of these and other derivative instruments that the Fund may use are described under "Investment Objectives and Policies" in the SAI.

The Fund's use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other more traditional investments. Certain derivative transactions may have a leveraging effect on the Fund. For example, a small investment in a derivative instrument may have a significant impact on the Fund's exposure to interest rates, currency exchange rates or other investments. As a result, a relatively small price movement in a derivative instrument may cause an immediate and substantial loss or gain. The Fund may engage in such transactions regardless of whether the Fund owns the asset, instrument or components of the index underlying the derivative instrument. The Fund may invest a significant portion of its assets in these types of instruments. If it does, the Fund's investment exposure could far exceed the value of its portfolio securities and its investment performance could be primarily dependent upon securities it does not own. A description of various risks associated with particular derivative instruments is included in "Investment Objectives and Policies" in the SAI. The following provides a more general discussion of important risk factors relating to all derivative instruments that may be used by the Fund.

CPI Swap. A CPI swap is a fixed maturity, OTC derivative transaction in which the investor receives the "realized" rate of inflation as measured by the CPI over the life of the swap. The investor in turn pays a fixed annualized rate over the life of the swap. This fixed rate is often referred to as the "breakeven inflation" rate and is generally representative of the difference between treasury yields and TIPS yields of similar maturities at the initiation of the swap. CPI swaps are typically in "bullet" format, where all cash flows are exchanged at maturity. In addition to counterparty risk, CPI swaps are also subject to inflation risk, where the swap can potentially lose value if the realized rate of inflation over the life of the swap is less than the fixed market implied inflation rate (fixed breakeven rate) that the investor agrees to pay at the initiation of the swap.

Management Risk. Derivative products are highly specialized instruments that require investment techniques and risk analyses different from those associated with stocks and bonds. The use of a derivative requires an understanding not only of the underlying instrument but also of the derivative itself, without the benefit of observing the performance of the derivative under all possible market conditions.

Counterparty Risk (including Credit Risk). The use of certain derivative instruments involves the risk that a loss may be sustained as a result of

the failure of another party to the contract (usually referred to as a "counterparty") to make required payments or otherwise comply with the contract's terms. Additionally, a short position in a credit default swap could result in losses if the Fund does not correctly evaluate the creditworthiness of the company on which the credit default swap is based. Counterparty risk also refers to the risks of having concentrated exposure to a counterparty.

Market and Fund Liquidity Risk. Liquidity risk exists when a particular derivative instrument is difficult to purchase or sell. If a derivative transaction is particularly large or if the relevant market is illiquid (as is the case with many privately negotiated derivatives), it may not be possible to initiate a transaction or liquidate a position at an advantageous time or price. Liquidity risk also refers to the risk that the Fund may be required to hold additional cash or sell other investments in order to obtain cash to close out derivatives or meet the liquidity demands that derivatives can create to make payments of margin, collateral, or settlement payments to counterparties. The Fund may have to sell a security at a disadvantageous time or price to meet such obligations.

Leverage Risk. Because many derivatives have a leverage component, adverse changes in the value or level of the underlying asset, reference rate or index could result in a loss substantially greater than the amount invested in the derivative itself. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. When the Fund uses derivatives for leverage, investments in the Fund will tend to be more volatile, resulting in larger gains or losses in response to market changes. Leveraging transactions pursued by the Fund may increase its duration and sensitivity to interest rate risks.

Lack of Availability. Because the markets for certain derivative instruments (including markets located in foreign countries) are relatively new and still developing, suitable derivatives transactions may not be available in all circumstances for risk management or other purposes. Upon the expiration of a particular contract, a portfolio manager may wish to retain the Fund's position in the derivative instrument by entering into a similar contract, but may be unable to do so if the counterparty to the original contract is unwilling to enter into the new contract and no other appropriate counterparty can be found. There is no assurance that the Fund will engage in derivatives transactions at any time or from time to time. The Fund's ability to use derivatives may also be limited by certain regulatory and tax considerations.

Correlation Risk. In certain cases, the value of derivatives may not correlate perfectly, or at all, with the value of the assets, reference rates or indexes they are designed to closely track. For example, a swap agreement on an ETF would not correlate perfectly with the index upon which the ETF is based because the fund's return is net of fees and expenses. In this regard, the Fund seeks to achieve its investment objective, in part, by investing in derivatives positions that are designed to closely track the performance (or inverse performance) of an index on a daily basis. However, the overall investment strategies of the Fund is not designed or expected to produce returns which replicate the

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performance (or inverse performance) of the particular index, and the degree of variation could be substantial, particularly over longer periods. There are a number of factors which may prevent the Fund, or derivatives or other strategies used by the Fund, from achieving a desired correlation (or inverse correlation) with an index. These may include, but are not limited to: (i) the impact of fund fees, expenses and transaction costs, including borrowing and brokerage costs/bid-ask spreads, which are not reflected in index returns; (ii) differences in the timing of daily calculations of the value of an index and the timing of the valuation of derivatives, securities and other assets held by the Fund and the determination of the NAV of Fund shares; (iii) disruptions or illiquidity in the markets for derivative instruments or securities in which the Fund invests; (iv) the Fund having exposure to or holding less than all of the securities in the underlying index and/or having exposure to or holding securities not included in the underlying index; (v) large or unexpected movements of assets into and out of the Fund (due to share purchases or redemptions, for example), potentially resulting in the Fund being over- or under-exposed to the index; (vi) the impact of accounting standards or changes thereto; (vii) changes to the applicable index that are not disseminated in advance; (viii) a possible need to conform the Fund's portfolio holdings to comply with investment restrictions or policies or regulatory or tax law requirements; and (ix) fluctuations in currency exchange rates.

Market and Other Risks. Like most other investments, derivative instruments are subject to the risk that the market value of the instrument will change in a way detrimental to the Fund's interest. If a portfolio manager incorrectly forecasts the values of securities, currencies or interest rates or other economic factors in using derivatives for the Fund, the Fund might have been in a better position if it had not entered into the transaction at all. While some strategies involving derivative instruments can reduce the risk of loss, they can also reduce the opportunity for gain or even result in losses by offsetting favorable price movements in other Fund investments. The regulation of the derivatives markets has increased over the past several years, and additional future regulation of the derivatives markets may make derivatives more costly, may limit the availability or reduce the liquidity of derivatives, or may otherwise adversely affect the value or performance of derivatives. Any such adverse future developments could impair the effectiveness or raise the costs of the Fund's derivative transactions, or impede the employment of the Fund's derivatives strategies, or adversely affect the Fund's performance. Other risks in using derivatives include the risk of mispricing and/or improper valuation of derivatives. Many derivatives, in particular privately negotiated derivatives, are complex and often valued subjectively. Improper valuations can result in increased cash payment requirements to counterparties or a loss of value to the Fund. Also, the value of derivatives may not correlate perfectly, or at all, with the value of the assets, reference rates or indexes they are designed to closely track. For example, a swap agreement on an exchange-traded fund would not correlate perfectly with the index upon which the exchange-traded fund is based because the fund's return is net of fees and expenses. In addition, the Fund's use of derivatives may cause the Fund to realize

higher amounts of short-term capital gains (generally taxed at ordinary income tax rates) than if the Fund had not used such instruments.

Operational and Legal Risks. Using derivatives is also subject to operational and legal risks. Operational risk generally refers to the risk related to potential operational issues, including documentation issues, settlement issues, systems failures, inadequate controls, and human error. Legal risk generally refers to insufficient documentation, insufficient capacity or authority of counterparty, or legality or enforceability of a contract.

Exchange-Traded Notes (ETNs)

ETNs are senior, unsecured, unsubordinated debt securities whose returns are linked to the performance of a particular market benchmark or strategy minus applicable fees. ETNs are traded on an exchange (e.g., the NYSE) during normal trading hours. However, investors can also hold the ETN until maturity. At maturity, the issuer pays to the investor a cash amount equal to the principal amount, subject to the day's market benchmark or strategy factor.

Delayed Funding Loans and Revolving Credit Facilities

The Fund may also enter into, or acquire participations in, delayed funding loans and revolving credit facilities, in which a lender agrees to make loans up to a maximum amount upon demand by the borrower during a specified term. These commitments may have the effect of requiring the Fund to increase its respective investments in a company at a time when it might not otherwise decide to do so (including at a time when the company's financial condition makes it unlikely that such amounts will be repaid). Delayed funding loans and revolving credit facilities are subject to credit, interest rate and liquidity risk and the risks of being a lender.

When-Issued, Delayed Delivery and Forward Commitment Transactions

The Fund may purchase or sell securities that it is eligible to purchase or sell on a when-issued basis, may purchase or sell such securities for delayed delivery and may make contracts to purchase or sell such securities for a fixed price at a future date beyond normal settlement time (forward commitments). When-issued transactions, delayed delivery purchases and forward commitments involve a risk of loss if the value of the securities declines prior to the settlement date. This risk is in addition to the risk that the Fund's other assets will decline in value. Therefore, these transactions may result in a form of leverage and increase the Fund's overall investment exposure. Typically, no income accrues on securities the Fund has committed to purchase prior to the time delivery of the securities is made. When the Fund has sold a security on a when-issued, delayed delivery or forward commitment basis, the Fund does not participate in future gains or losses with respect to the security. If the other party to a transaction fails to pay for the securities, the Fund could suffer a loss. Additionally, when selling a security on a when-issued, delayed delivery or forward commitment

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basis without owning the security, the Fund will incur a loss if the security's price appreciates in value such that the security's price is above the agreed-upon price on the settlement date.

Investment in or Exposure to Other Funds

The Fund may invest in and take derivative positions on securities of other investment companies, such as open-end or closed-end management investment companies, including ETFs, which may include investment companies advised by PIMCO or another investment adviser, or in pooled accounts or other unregistered accounts or investment vehicles to the extent permitted by the 1940 Act, the rules and regulations thereunder or any exemptive relief therefrom. The Fund may invest in and take derivative positions on other investment companies to gain broad market or sector exposure, including but not limited to during periods when it has large amounts of uninvested cash or when PIMCO believes share prices of other investment companies offer attractive values. Through investment exposure to an investment company or other pooled vehicle, the Fund may indirectly bear investment advisory fees, supervisory and administrative fees, service fees and other fees which are in addition to the fees the Fund pays its service providers. To the extent the Fund gains exposure to other investment companies that are advised by PIMCO, PIMCO expects to select such investments without considering or canvassing the universe of available unaffiliated investment companies.

The Fund operates as a "fund-of-funds." The expenses associated with investing in a fund of funds are generally higher than those for funds that do not invest in other funds. The cost of investing in a fund of funds, such as the Fund, will generally be higher than the cost of investing in a fund that invests directly in individual stocks and bonds. By investing in the Fund, an investor will indirectly bear fees and expenses charged by third-party managed funds in addition to the Fund's direct fees and expenses. Similarly, the gross performance of the Fund's derivatives on PIMCO Active Fixed-Income ETFs will be reduced by the fees and expenses of such PIMCO Active Fixed-Income ETFs. In non-normal circumstances, the Fund may also invest directly in shares of underlying PIMCO funds and investors will indirectly bear fees and expenses charged by such underlying PIMCO funds. PIMCO will not waive any fees or expenses of an underlying PIMCO fund, embedded in the returns of the derivatives entered into by the Fund. In addition, the use of a fund of funds structure could affect the timing, amount and character of distributions to the shareholders and may therefore increase the amount of taxes payable by shareholders.

expenses of an underlying PIMCO fund that are embedded within the derivative from the investing fund's management fees. As a result, PIMCO may receive management fee revenue from the increase in assets in the underlying PIMCO fund associated with any hedging activity by the counterparty to the investing fund's derivatives, as it is common for such counterparties to hedge their derivatives exposure by investing directly in the underlying reference asset, which fees are in addition to the Fund's management fees.

Participation in a cash sweep program where the Fund's uninvested cash balance is used to purchase shares of affiliated or unaffiliated money market funds or cash management pooled investment vehicles at the end of each day subjects the Fund to the risks associated with the underlying money market funds or cash management pooled investment vehicles, including liquidity risk. As a shareholder of a money market fund or cash management pooled investment vehicle, the Fund would indirectly bear the fees and expenses of the underlying fund or account which are in addition to the fees the Fund pays its service providers.

Subject to the restrictions and limitations of the 1940 Act, and the rules and regulations thereunder and any exemptive relief therefrom, the Fund may, in the future, elect to pursue its investment objective either by investing directly in securities or by investing in one or more underlying investment vehicles or companies that have substantially similar investment objectives and policies as the Fund.

Small-Cap and Mid-Cap Companies

Investments in small-cap and mid-cap companies involve greater risk than investments in large-capitalization companies. Small- and mid-cap companies may not have an established financial history, which can present valuation challenges. The equity securities of small- and mid-cap companies may be subject to increased market fluctuations, due to less liquid markets and more limited managerial and financial resources or they may depend on a small or inexperienced management group. The Fund's investment in small- and mid-cap companies may increase the volatility of the Fund's portfolio.

Short Sales

The Fund may make short sales as part of its overall portfolio management strategies or to offset a potential decline in value of a security. A short sale involves the sale of a security that is borrowed from a broker or other institution to complete the sale. Short sales expose the Fund to the risk that it will be required to acquire, convert or exchange securities to replace the borrowed securities (also known as "covering" the short position) at a time when the securities sold short have appreciated in value, thus resulting in a loss to the Fund. A short sale is "against the box" to the extent that the Fund contemporaneously owns, or has the right to obtain at no added cost, securities identical to those sold short. The Fund may engage in short selling to the extent permitted by the 1940 Act and rules and interpretations thereunder and other federal securities laws. To the

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extent the Fund engages in short selling in foreign (non-U.S.) jurisdictions, the Fund will do so to the extent permitted by the laws and regulations of such jurisdiction.

Fund Distribution Rates

The Fund's distribution rates may be affected by numerous factors, including but not limited to changes in realized and projected market returns, fluctuations in market interest rates, Fund performance, and other factors. There can be no assurance that a change in market conditions or other factors will not result in a change in the Fund's distribution rate or that the rate will be sustainable in the future.

For instance, during periods of low or declining interest rates, the Fund's distributable income and dividend levels may decline for many reasons. For example, the Fund may have to deploy uninvested assets (whether from purchases of Fund shares, proceeds from matured, traded or called debt obligations or other sources) in new, lower yielding instruments. Additionally, payments from certain instruments that may be held by the Fund (such as variable and floating rate securities) may be negatively impacted by declining interest rates, which may also lead to a decline in the Fund's distributable income and dividend levels.

Illiquid Investments

The Fund may invest up to 15% of its net assets (taken at the time of investment) in illiquid investments that are assets. Certain illiquid investments may require pricing at fair value as determined in good faith under the supervision of the Board of Trustees. A portfolio manager may be subject to significant delays in disposing of illiquid investments, and transactions in illiquid investments may entail registration expenses and other transaction costs that are higher than those for transactions in liquid investments. The term "illiquid investments" for this purpose means investments that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. Restricted securities, i.e., securities subject to legal or contractual restrictions on resale, may be illiquid. However, some restricted securities (such as securities issued pursuant to Rule 144A under the Securities Act of 1933, as amended, and certain commercial paper) may be treated as liquid (i.e., classified by the Fund in a liquidity category other than "illiquid" pursuant to the Fund's liquidity risk management procedures), although they may be relatively less liquid than registered securities traded on established secondary markets. Additional discussion of illiquid investments and related regulatory limits and requirements is available under "Investment Objectives and Policies" in the SAI.

Loans of Portfolio Securities

For the purpose of achieving income, the Fund may lend its portfolio securities to brokers, dealers, and other financial institutions provided that a number of conditions are satisfied, including that the loan is fully collateralized. Please see "Investment Objectives and Policies" in the SAI for details. When the Fund lends portfolio securities, its investment performance will continue to reflect changes in the value of the securities loaned, and the Fund will also receive a fee or interest on the

collateral. Securities lending involves the risk of loss of rights in the collateral or delay in recovery of the collateral if the borrower fails to return the security loaned or becomes insolvent. The Fund may pay lending fees to a party arranging the loan, which may be an affiliate of the Fund. Cash collateral received by the Fund in securities lending transactions may be invested in short-term liquid fixed income instruments or in money market or short-term mutual funds, or similar investment vehicles, including affiliated money market or short-term mutual funds. As a shareholder of an investment company or other pooled vehicle, the Fund may indirectly bear investment advisory fees, supervisory and administrative fees, service fees and other fees which are in addition to the fees the Fund pays its service providers. To the extent such cash collateral is invested in an affiliated money market or short-term mutual fund, such fees generally will not be waived, and PIMCO expects to select such an investment without considering or canvassing the universe of available unaffiliated investment companies. The Fund bears the risk of such investments.

Portfolio Turnover

The length of time the Fund has held a particular security is not generally a consideration in investment decisions. A change in the securities held by the Fund is known as "portfolio turnover." When the portfolio managers deem it appropriate and particularly during periods of volatile market movements, the Fund may engage in frequent and active trading of portfolio securities to achieve its investment objective. To the extent that Creation Unit purchases from and redemptions by the Fund are effected in cash, frequent purchases and redemptions may increase the rate of portfolio turnover. Higher portfolio turnover (e.g., an annual rate greater than 100% of the average value of the Fund's portfolio) involves correspondingly greater expenses to the Fund, including brokerage commissions or dealer markups and other transaction costs on the sale of securities and reinvestments in other securities. Such sales may also result in realization of taxable capital gains, including short-term capital gains (which are generally taxed at ordinary income tax rates). The trading costs and tax effects associated with portfolio turnover may adversely affect the Fund's performance. In addition to indirectly bearing the expenses associated with portfolio turnover of the PIMCO Active Fixed-Income ETFs and third-party managed funds in which it invests, the Fund will directly bear these expenses to the extent that it invests in other securities and instruments. Please see the Fund's "Fund Summary-Portfolio Turnover" or the "Financial Highlights" in this prospectus for the portfolio turnover rate of the Fund during the last fiscal year. In addition, large movements of cash into or out of the Fund may negatively impact the Fund's ability to achieve its investment objective or maintain a consistent level of operating expenses.

Temporary Defensive Positions

For temporary defensive purposes, the Fund may invest without limit in U.S. debt securities, including taxable securities and short-term money market securities in attempting to respond to adverse market, economic, political, or other conditions, as determined by PIMCO. When the Fund engages in such strategies, it may not achieve its investment objective.

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From time to time, as the prevailing market and interest rate environments warrant, and at the discretion of its portfolio manager, some portion of the Fund's total net assets may be uninvested. In such cases, Fund assets will be held in cash in the Fund's custody account. Cash assets are generally not income-generating and would impact the Fund's performance.

Changes in Investment Objectives and Policies

The investment objective of the Fund is non-fundamental and may be changed by the Board of Trustees without shareholder approval. Unless otherwise stated, all other investment policies of the Fund may be changed by the Board of Trustees without shareholder approval. In addition, the Trust may determine to cease operating the Fund as an "exchange-traded" fund and cause the Fund's shares to stop trading on a securities exchange.

Percentage Investment Limitations

Unless otherwise stated, all percentage limitations on Fund investments listed in this prospectus will apply at the time of investment. The Fund would not violate these limitations unless an excess or deficiency occurs or exists immediately after and as a result of an investment. The Fund has adopted a non-fundamental investment policy to invest at least 80% of its assets in investments suggested by its name. For purposes of this policy, the term "assets" means net assets plus the amount of any borrowings for investment purposes.

Credit Ratings and Unrated Securities

Rating agencies are private services that provide ratings of the credit quality of fixed income securities, including convertible securities. Appendix A to this prospectus describes the various ratings assigned to fixed income securities by Moody's, S&P and Fitch. Ratings assigned by a rating agency are not absolute standards of credit quality and do not evaluate market risks. Rating agencies may fail to make timely changes in credit ratings and an issuer's current financial condition may be better or worse than a rating indicates. The Fund will not necessarily sell a security when its rating is reduced below its rating at the time of purchase. The ratings of a fixed income security may change over time. Moody's, S&P and Fitch monitor and evaluate the ratings assigned to securities on an ongoing basis. As a result, debt instruments held by the Fund could receive a higher rating or a lower rating during the period in which they are held by the Fund. PIMCO does not rely solely on credit ratings, and develops its own analysis of issuer credit quality.

The Fund may purchase unrated securities (which are not rated by a rating agency) if PIMCO determines, in its sole discretion, that the security is of comparable quality to a rated security that the Fund may purchase. In making ratings determinations, PIMCO may take into account different factors than those taken into account by rating agencies, and PIMCO's rating of a security may differ from the rating that a rating agency may have given the same security. Unrated securities may be less liquid than comparable rated securities and involve the risk that the portfolio manager may not accurately evaluate the security's comparative credit rating. Analysis of the creditworthiness of issuers of high yield securities may be more complex than for issuers

of higher-quality fixed income securities. To the extent that the Fund invests in high yield and/or unrated securities, the Fund's success in achieving its investment objective may depend more heavily on the portfolio manager's creditworthiness analysis than if the Fund invested exclusively in higher-quality and higher-rated securities.

Other Investments and Techniques

The Fund may invest in other types of securities and use a variety of investment techniques and strategies that are not described in this prospectus. These securities and techniques may subject the Fund to additional risks. Please see the SAI for additional information about the securities and investment techniques described in this prospectus and about additional securities and techniques that may be used by the Fund.

Geopolitical Conflicts

The occurrence of geopolitical conflicts, war or terrorist activities could have adverse impacts on markets in various and unpredictable ways. For example, following Russia's large-scale invasion of Ukraine in February 2022, Russia, and other countries, persons and entities that were viewed as having provided material aid to Russia's aggression against Ukraine, became the subject of economic sanctions and import and export controls imposed by countries throughout the world, including the United States. Such measures have had and may continue to have an adverse effect on the Russian, Belarusian and other securities and economies. Additional examples include, but are not limited to, heightened concerns of trade disputes, which could result in increased tariffs, trade restrictions or other retaliatory countermeasures. The extent, duration and impact of geopolitical conflicts and related market impacts are difficult to ascertain, but could be significant and could have significant adverse effects on regional and global economies and the markets for certain securities and commodities, such as oil, natural gas, steel and aluminum, as well as other sectors, and on the Fund's investments.

Cyber Security

As the use of complex information technology and communications systems, including cloud-based technology, has become more prevalent and interconnected in the course of business, the Fund has become potentially more susceptible to operational and information security risks resulting from breaches in cyber security despite the efforts of PIMCO, the Fund, or their service providers to adopt technologies, processes, and practices intended to mitigate these risks. Disruptions or failures that affect services providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect PIMCO or the Fund, including by causing losses or impairing PIMCO's or the Fund's operations. Information relating to the Fund's investments has been and will in the future be delivered electronically, which can give rise to a number of risks, including, but not limited to, the risks that such communications may contain computer viruses or other defects, may not be accurately replicated on other systems, or may be intercepted, deleted or interfered with, without the knowledge of the sender or the intended recipient. A breach in cyber security refers to

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both intentional and unintentional cyber events that may, among other things, cause the Fund to lose proprietary information, suffer data corruption and/or destruction or lose operational capacity, result in the unauthorized release or other misuse of confidential information, or otherwise disrupt normal business operations. Geopolitical tensions can increase the scale and sophistication of deliberate cybersecurity attacks, particularly those from nation-states or from entities with nation-state backing, who may desire to use cybersecurity attacks to cause damage or create leverage against geopolitical rivals. Cyber security breaches may involve unauthorized access to the digital information systems that support the Fund (e.g., through "hacking," ransomware or malicious software coding) or outside attacks such as denial-of-service attacks (i.e., efforts to make network services unavailable to intended users), but may also result from intentionally or unintentionally harmful acts of PIMCO personnel. In addition, cyber security breaches involving third party service providers that provide services to PIMCO or the Fund (including but not limited to vendors, advisers, sub-advisers, administrators, transfer agents, regulatory authorities, custodians, registry operators, distributors and other third parties), trading counterparties and issuers in which the Fund invests can also subject the Fund to many of the same risks associated with direct cyber security breaches. PIMCO's use of cloud-based service providers could heighten or change these risks. In addition, work-from-home arrangements by the Fund, PIMCO and its service providers could increase all of the above risks, create additional data and information accessibility concerns, and make the Fund, PIMCO or its service providers susceptible to operational disruptions, any of which could adversely impact their operations. Cyber security failures or breaches may result in financial losses to the Fund and its shareholders. For example, cyber security failures or breaches involving trading counterparties or issuers in which the Fund invests could adversely impact such counterparties or issuers and cause the Fund's investments to lose value. These failures or breaches may also result in disruptions to business operations, potentially resulting in financial losses; interference with the Fund's ability to calculate its NAV, process shareholder transactions or otherwise transact business with shareholders; impediments to trading; violations of applicable privacy and other laws; regulatory fines; penalties; third party claims in litigation; reputational damage; reimbursement or other compensation costs; additional compliance and cyber security risk management costs and other adverse consequences. In addition, substantial costs may be incurred in order to prevent any cyber incidents in the future.

Like with operational risk in general, the Fund has established business continuity plans and risk management systems designed to reduce the risks associated with cyber security. However, there are inherent limitations in these plans and systems, including that certain risks may not have been identified, in large part because different or unknown threats may emerge in the future. As such, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers in which the Fund may invest, trading counterparties or third party service providers to the Fund. Such entities have experienced cyber attacks and other attempts to gain unauthorized access to systems from time to time, and there is

no guarantee that efforts to prevent or mitigate the effects of such attacks or other attempts to gain unauthorized access will be successful. There is also a risk that cyber security breaches may not be detected. The Fund and its shareholders may suffer losses as a result of a cyber security breach related to the Fund, its service providers, trading counterparties or the issuers in which the Fund invests.

Regulatory Changes

Financial entities, such as investment companies and investment advisers, are generally subject to extensive government regulation and intervention. Government regulation and/or intervention may change the way the Fund is regulated, affect the expenses incurred directly by the Fund and the value of its investments, and limit and/or preclude the Fund's ability to achieve its investment objective. Government regulation may change frequently and may have significant adverse consequences. The Fund and the investment adviser have historically been eligible for exemptions from certain regulations. However, there is no assurance that the Fund and the investment adviser will continue to be eligible for such exemptions. Actions by governmental entities may also impact certain instruments in which the Fund invests.

Moreover, government regulation may have unpredictable and unintended effects. Legislative or regulatory actions to address perceived liquidity or other issues in fixed income markets generally, or in particular markets such as the municipal securities market, may alter or impair the Fund's ability to pursue its investment objective or utilize certain investment strategies and techniques.

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PIMCO ETF Trust

Financial Highlights

Because the Fund has not commenced operations as of the date of this prospectus, audited financial highlights are not available.

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Prospectus

Appendix A

Description of Securities Ratings

The Fund's investments may range in quality from securities rated in the lowest category in which the Fund is permitted to invest to securities rated in the highest category (as rated by Moody's, S&P or Fitch, or, if unrated, determined by PIMCO to be of comparable quality) to securities so rated. The percentage of the Fund's assets invested in securities in a particular rating category will vary. The following terms are generally used to describe the credit quality of fixed income securities:

High Quality Debt Securities are those rated in one of the two highest rating categories (the highest category for commercial paper) or, if unrated, deemed comparable by PIMCO.

Investment Grade Debt Securities are those rated in one of the four highest rating categories, or, if unrated, deemed comparable by PIMCO.

Below Investment Grade High Yield Securities ("Junk Bonds"), are those rated lower than Baa by Moody's, BBB by S&P or Fitch, and comparable securities. They are deemed predominantly speculative with respect to the issuer's ability to repay principal and interest.

The following is a description of Moody's, S&P and Fitch's rating categories applicable to fixed income securities.

Moody's Ratings

Global Long-Term Rating Scale

Ratings assigned on Moody's global long-term rating scale are forward-looking opinions of the relative credit risks of financial obligations issued by non-financial corporates, financial institutions, structured finance vehicles, project finance vehicles, and public sector entities. Long-term ratings are assigned to issuers or obligations with an original maturity of eleven months or more and reflect both on the likelihood of a default or impairment on contractual financial obligations and the expected financial loss suffered in the event of default or impairment.

Aaa: Obligations rated Aaa are judged to be of the highest quality, subject to the lowest level of credit risk.

Aa: Obligations rated Aa are judged to be of high quality and are subject to very low credit risk.

A: Obligations rated A are judged to be upper-medium grade and are subject to low credit risk.

Baa: Obligations rated Baa are judged to be medium-grade and subject to moderate credit risk and as such may possess certain speculative characteristics.

Ba: Obligations rated Ba are judged to be speculative and are subject to substantial credit risk.

B: Obligations rated B are considered speculative and are subject to high credit risk.

Caa: Obligations rated Caa are judged to be speculative of poor standing and are subject to very high credit risk.

Ca: Obligations rated Ca are highly speculative and are likely in, or very near, default, with some prospect of recovery of principal and interest.

C: Obligations rated C are the lowest rated and are typically in default, with little prospect for recovery of principal or interest.

Moody's appends numerical modifiers 1, 2, and 3 to each generic rating classification from Aa through Caa. The modifier 1 indicates that the obligation ranks in the higher end of its generic rating category; the modifier 2 indicates a mid-range ranking; and the modifier 3 indicates a ranking in the lower end of that generic rating category. Additionally, a "(hyb)" indicator is appended to all ratings of hybrid securities issued by banks, insurers, finance companies, and securities firms.*

* By their terms, hybrid securities allow for the omission of scheduled dividends, interest, or principal payments, which can potentially result in impairment if such an omission occurs. Hybrid securities may also be subject to contractually allowable write-downs of principal that could result in impairment. Together with the hybrid indicator, the long-term obligation rating assigned to a hybrid security is an expression of the relative credit risk associated with that security.

Medium-Term Note Program Ratings

Moody's assigns provisional ratings to medium-term note (MTN) or similar programs and definitive ratings to the individual debt securities issued from them (referred to as drawdowns or notes).

MTN program ratings are intended to reflect the ratings likely to be assigned to drawdowns issued from the program with the specified priority of claim (e.g., senior or subordinated). To capture the contingent nature of a program rating, Moody's assigns provisional ratings to MTN programs. A provisional rating is denoted by a (P) in front of the rating.

The rating assigned to a drawdown from a rated MTN or bank/deposit note program is definitive in nature, and may differ from the program rating if the drawdown is exposed to additional credit risks besides the issuer's default, such as links to the defaults of other issuers, or has other structural features that warrant a different rating. In some circumstances, no rating may be assigned to a drawdown.

Moody's encourages market participants to contact Moody's Ratings Desks or visit moodys.com directly if they have questions regarding ratings for specific notes issued under a medium-term note program. Unrated notes issued under an MTN program may be assigned an NR (not rated) symbol.

Global Short-Term Rating Scale

Ratings assigned on Moody's global short-term rating scale are forward-looking opinions of the relative credit risks of financial obligations issued by non-financial corporates, financial institutions, structured finance vehicles, project finance vehicles, and public sector entities. Short-term ratings are assigned to obligations with an original maturity of thirteen months or less and reflect both on the likelihood of a default or impairment on contractual financial obligations and the expected financial loss suffered in the event of default or impairment.

Moody's employs the following designations to indicate the relative repayment ability of rated issuers:

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P-1: Ratings of Prime-1 reflect a superior ability to repay short-term obligations.

P-2: Ratings of Prime-2 reflect a strong ability to repay short-term obligations.

P-3: Ratings of Prime-3 reflect an acceptable ability to repay short-term obligations.

NP: Issuers (or supporting institutions) rated Not Prime do not fall within any of the Prime rating categories.

National Scale Long-Term Ratings

Moody's long-term National Scale Ratings (NSRs) are opinions of the relative creditworthiness of issuers and financial obligations within a particular country. NSRs are not designed to be compared among countries; rather, they address relative credit risk within a given country. Moody's assigns national scale ratings in certain local capital markets in which investors have found the global rating scale provides inadequate differentiation among credits or is inconsistent with a rating scale already in common use in the country.

In each specific country, the last two characters of the rating indicate the country in which the issuer is located or the financial obligation was issued (e.g.,Aaa.ke for Kenya).

Aaa.n: Issuers or issues rated Aaa.n demonstrate the strongest creditworthiness relative to other domestic issuers and issuances.

Aa.n: Issuers or issues rated Aa.n demonstrate very strong creditworthiness relative to other domestic issuers and issuances.

A.n: Issuers or issues rated A.n demonstrate above-average creditworthiness relative to other domestic issuers and issuances.

Baa.n: Issuers or issues rated Baa.n demonstrate average creditworthiness relative to other domestic issuers and issuances.

Ba.n: Issuers or issues rated Ba.n demonstrate below-average creditworthiness relative to other domestic issuers and issuances.

B.n: Issuers or issues rated B.n demonstrate weak creditworthiness relative to other domestic issuers and issuances.

Caa.n: Issuers or issues rated Caa.n demonstrate very weak creditworthiness relative to other domestic issuers and issuances.

Ca.n: Issuers or issues rated Ca.n demonstrate extremely weak creditworthiness relative to other domestic issuers and issuances.

C.n: Issuers or issues rated C.n demonstrate the weakest creditworthiness relative to other domestic issuers and issuances.

National Scale Short-Term Ratings

Moody's short-term NSRs are opinions of the ability of issuers or issuances in a given country, relative to other domestic issuers or issuances, to repay debt obligations that have an original maturity not

exceeding thirteen months. Short-term NSRs in one country should not be compared with short-term NSRs in another country, or with Moody's global ratings. There are four categories of short-term national scale ratings, generically denoted N-1 through N-4 as defined below.

In each specific country, the first two letters indicate the country in which the issuer is located (e.g., KE-1 through KE-4 for Kenya).

N-1: N-1 issuers or issuances represent the strongest likelihood of repayment of short-term debt obligations relative to other domestic issuers or issuances.

N-2: N-2 issuers or issuances represent an above average likelihood of repayment of short-term debt obligations relative to other domestic issuers or issuances.

N-3: N-3 issuers or issuances represent an average likelihood of repayment of short-term debt obligations relative to other domestic issuers or issuances.

N-4: N-4 issuers or issuances represent a below average likelihood of repayment of short-term debt obligations relative to other domestic issuers or issuances.

The short-term rating symbols P-1.za, P-2.za, P-3.za and NP.za are used in South Africa.

Short-Term Obligation Ratings

The Municipal Investment Grade (MIG) scale is used for U.S. municipal cash flow notes, bond anticipation notes and certain other short-term obligations, which typically mature in three years or less.

MIG 1: This designation denotes superior credit quality. Excellent protection is afforded by established cash flows, highly reliable liquidity support, or demonstrated broad-based access to the market for refinancing.

MIG 2: This designation denotes strong credit quality. Margins of protection are ample, although not as large as in the preceding group.

MIG 3: This designation denotes acceptable credit quality. Liquidity and cash-flow protection may be narrow, and market access for refinancing is likely to be less well-established.

SG: This designation denotes speculative-grade credit quality. Debt instruments in this category may lack sufficient margins of protection.

Demand Obligation Ratings

For variable rate demand obligations (VRDOs), a two-component rating is assigned. Moody's assigns both a long-term rating and a short-term payment obligation rating. The long-term rating addresses the issuer's ability to meet scheduled principal and interest payments. The short-term payment obligation rating addresses the ability of the issuer or the liquidity provider to meet any purchase price payment obligation resulting from optional tenders ("on demand") and/or mandatory tenders of the VRDO. The short-term payment obligation rating uses the Variable Municipal Investment Grade (VMIG) scale.

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For VRDOs, Moody's typically assigns a VMIG rating if the frequency of the payment obligation is less than every three years. If the frequency of the payment obligation is less than three years, but the obligation is payable only with remarketing proceeds, the VMIG short-term rating is not assigned and it is denoted as "NR".

VMIG 1: This designation denotes superior credit quality. Excellent protection is afforded by the superior short-term credit strength of the liquidity provider and structural and legal protections.

VMIG 2: This designation denotes strong credit quality. Good protection is afforded by the strong short-term credit strength of the liquidity provider and structural and legal protections.

VMIG 3: This designation denotes acceptable credit quality. Adequate protection is afforded by the satisfactory short-term credit strength of the liquidity provider and structural and legal protections.

SG: This designation denotes speculative-grade credit quality. Demand features rated in this category may be supported by a liquidity provider that does not have a sufficiently strong short-term rating or may lack the structural or legal protections.

S&P Global Ratings

Long-Term Issue Credit Ratings*

Issue credit ratings are based, in varying degrees, on S&P Global Ratings' ("S&P") analysis of the following considerations:

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Likelihood of payment-capacity and willingness of the obligor to meet its financial commitments on an obligation in accordance with the terms of the obligation;

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Nature and provisions of the financial obligation and the promise S&P imputes; and

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Protection afforded by, and relative position of, the financial obligation in the event of a bankruptcy, reorganization, or other arrangement under the laws of bankruptcy and other laws affecting creditors' rights.

Issue ratings are an assessment of default risk, but may incorporate an assessment of relative seniority or ultimate recovery in the event of default. Junior obligations are typically rated lower than senior obligations, to reflect lower priority in bankruptcy, as noted above. (Such differentiation may apply when an entity has both senior and subordinated obligations, secured and unsecured obligations, or operating company and holding company obligations.)

Investment Grade

AAA: An obligation rated 'AAA' has the highest rating assigned by S&P. The obligor's capacity to meet its financial commitments on the obligation is extremely strong.

AA: An obligation rated 'AA' differs from the highest-rated obligations only to a small degree. The obligor's capacity to meet its financial commitments on the obligation is very strong.

A: An obligation rated 'A' is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligations in higher-rated categories. However, the obligor's capacity to meet its financial commitments on the obligation is still strong.

BBB: An obligation rated 'BBB' exhibits adequate protection parameters. However, adverse economic conditions or changing circumstances are more likely to weaken the obligor's capacity to meet its financial commitments on the obligation.

Speculative Grade

Obligations rated 'BB', 'B', 'CCC', 'CC', and 'C' are regarded as having significant speculative characteristics. 'BB' indicates the least degree of speculation and 'C' the highest. While such obligations will likely have some quality and protective characteristics, these may be outweighed by large uncertainties or major exposure to adverse conditions.

BB: An obligation rated 'BB' is less vulnerable to nonpayment than other speculative issues. However, it faces major ongoing uncertainties or exposure to adverse business, financial, or economic conditions that could lead to the obligor's inadequate capacity to meet its financial commitments on the obligation.

B: An obligation rated 'B' is more vulnerable to nonpayment than obligations rated 'BB', but the obligor currently has the capacity to meet its financial commitments on the obligation. Adverse business, financial, or economic conditions will likely impair the obligor's capacity or willingness to meet its financial commitments on the obligation.

CCC: An obligation rated 'CCC' is currently vulnerable to nonpayment, and is dependent upon favorable business, financial, and economic conditions for the obligor to meet its financial commitments on the obligation. In the event of adverse business, financial, or economic conditions, the obligor is not likely to have the capacity to meet its financial commitments on the obligation.

CC: An obligation rated 'CC' is currently highly vulnerable to nonpayment. The 'CC' rating is used when a default has not yet occurred, but S&P expects default to be a virtual certainty, regardless of the anticipated time to default.

C: An obligation rated 'C' is currently highly vulnerable to nonpayment, and the obligation is expected to have lower relative seniority or lower ultimate recovery compared with obligations that are rated higher.

D: An obligation rated 'D' is in default or in breach of an imputed promise. For non-hybrid capital instruments, the 'D' rating category is used when payments on an obligation are not made on the date due, unless S&P believes that such payments will be made within the next five business days in the absence of a stated grace period or within the earlier of the stated grace period or the next 30 calendar days. The 'D' rating also will be used upon the filing of a bankruptcy petition or the taking of similar action and where default on an obligation is a virtual certainty, for example due to automatic stay provisions. A rating on an obligation is lowered to 'D' if it is subject to a distressed debt restructuring.

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*Ratings from 'AA' to 'CCC' may be modified by the addition of a plus (+) or minus (-) sign to show relative standing within the rating categories.

Short-Term Issue Credit Ratings

A-1: A short-term obligation rated 'A-1' is rated in the highest category by S&P. The obligor's capacity to meet its financial commitments on the obligation is strong. Within this category, certain obligations are designated with a plus sign (+). This indicates that the obligor's capacity to meet its financial commitments on these obligations is extremely strong.

A-2: A short-term obligation rated 'A-2' is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligations in higher rating categories. However, the obligor's capacity to meet its financial commitments on the obligation is satisfactory.

A-3: A short-term obligation rated 'A-3' exhibits adequate protection parameters. However, adverse economic conditions or changing circumstances are more likely to weaken an obligor's capacity to meet its financial commitments on the obligation.

B: A short-term obligation rated 'B' is regarded as vulnerable and has significant speculative characteristics. The obligor currently has the capacity to meet its financial commitments; however, it faces major ongoing uncertainties that could lead to the obligor's inadequate capacity to meet its financial commitments.

C: A short-term obligation rated 'C' is currently vulnerable to nonpayment and is dependent upon favorable business, financial, and economic conditions for the obligor to meet its financial commitments on the obligation.

D: A short-term obligation rated 'D' is in default or in breach of an imputed promise. For non-hybrid capital instruments, the 'D' rating category is used when payments on an obligation are not made on the date due, unless S&P believes that such payments will be made within any stated grace period. However, any stated grace period longer than five business days will be treated as five business days. The 'D' rating also will be used upon the filing of a bankruptcy petition or the taking of a similar action and where default on an obligation is a virtual certainty, for example due to automatic stay provisions. A rating on an obligation is lowered to 'D' if it is subject to a distressed debt restructuring.

Dual Ratings: Dual ratings may be assigned to debt issues that have a put option or demand feature. The first component of the rating addresses the likelihood of repayment of principal and interest as due, and the second component of the rating addresses only the demand feature. The first component of the rating can relate to either a short-term or long-term transaction and accordingly use either short-term or long-term rating symbols. The second component of the rating relates to the put option and is assigned a short-term rating symbol (for example, 'AAA/A-1+' or 'A-1+/ A-1'). With U.S. municipal short-term demand debt, the U.S. municipal short-term note rating symbols are used for the first component of the rating (for example, 'SP-1+/A-1+').

Active Qualifiers

S&P uses the following qualifiers that limit the scope of a rating. The structure of the transaction can require the use of a qualifier such as a 'p' qualifier, which indicates the rating addresses the principal portion of the obligation only. A qualifier appears as a suffix and is part of the rating.

L: Ratings qualified with 'L' apply only to amounts invested up to federal deposit insurance limits.

p: This suffix is used for issues in which the credit factors, the terms, or both, that determine the likelihood of receipt of payment of principal are different from the credit factors, terms or both that determine the likelihood of receipt of interest on the obligation. The 'p' suffix indicates that the rating addresses the principal portion of the obligation only and that the interest is not rated.

prelim: Preliminary ratings, with the 'prelim' suffix, may be assigned to obligors or obligations, including financial programs, in the circumstances described below. Assignment of a final rating is conditional on the receipt by S&P of appropriate documentation. S&P reserves the right not to issue a final rating. Moreover, if a final rating is issued, it may differ from the preliminary rating.

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Preliminary ratings may be assigned to obligations, most commonly structured and project finance issues, pending receipt of final documentation and legal opinions.

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Preliminary ratings may be assigned to obligations that will likely be issued upon the obligor's emergence from bankruptcy or similar reorganization, based on late-stage reorganization plans, documentation, and discussions with the obligor. Preliminary ratings may also be assigned to the obligors. These ratings consider the anticipated general credit quality of the reorganized or post-bankruptcy issuer as well as attributes of the anticipated obligation(s).

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Preliminary ratings may be assigned to entities that are being formed or that are in the process of being independently established when, in S&P's opinion, documentation is close to final. Preliminary ratings may also be assigned to the obligations of these entities.

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Preliminary ratings may be assigned when a previously unrated entity is undergoing a well-formulated restructuring, recapitalization, significant financing or other transformative event, generally at the point that investor or lender commitments are invited. The preliminary rating may be assigned to the entity and to its proposed obligation(s). These preliminary ratings consider the anticipated general credit quality of the obligor, as well as attributes of the anticipated obligation(s), assuming successful completion of the transformative event. Should the transformative event not occur, S&P would likely withdraw these preliminary ratings.

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A preliminary recovery rating may be assigned to an obligation that has a preliminary issue credit rating.

A-4 Prospectus| PIMCO ETF Trust

Prospectus

t: This symbol indicates termination structures that are designed to honor their contracts to full maturity or, should certain events occur, to terminate and cash settle all their contracts before their final maturity date.

cir: This symbol indicates a Counterparty Instrument Rating (CIR), which is a forward-looking opinion about the creditworthiness of an issuer in a securitization structure with respect to a specific financial obligation to a counterparty (including interest rate swaps, currency swaps, and liquidity facilities). The CIR is determined on an ultimate payment basis; these opinions do not take into account timeliness of payment.

Inactive Qualifiers (no longer applied or outstanding)

*: This symbol indicated that the rating was contingent upon S&P receipt of an executed copy of the escrow agreement or closing documentation confirming investments and cash flows. Discontinued use in August 1998.

c: This qualifier was used to provide additional information to investors that the bank may terminate its obligation to purchase tendered bonds if the long-term credit rating of the issuer was lowered to below an investment-grade level and/or the issuer's bonds were deemed taxable. Discontinued use in January 2001.

G: The letter 'G' followed the rating symbol when a fund's portfolio consisted primarily of direct U.S. government securities.

i: This suffix was used for issues in which the credit factors, terms, or both that determine the likelihood of receipt of payment of interest are different from the credit factors, terms, or both that determine the likelihood of receipt of principal on the obligation. The 'i' suffix indicated that the rating addressed the interest portion of the obligation only. The 'i' suffix was always used in conjunction with the 'p' suffix, which addresses likelihood of receipt of principal. For example, a rated obligation could have been assigned a rating of 'AAApNRi' indicating that the principal portion was rated 'AAA' and the interest portion of the obligation was not rated.

pi: This qualifier was used to indicate ratings that were based on an analysis of an issuer's published financial information, as well as additional information in the public domain. Such ratings did not, however, reflect in-depth meetings with an issuer's management and therefore, could have been based on less comprehensive information than ratings without a 'pi' suffix. Discontinued use as of December 2014 and as of August 2015 for Lloyd's Syndicate Assessments.

pr: The letters 'pr' indicate that the rating was provisional. A provisional rating assumed the successful completion of a project financed by the debt being rated and indicates that payment of debt service requirements was largely or entirely dependent upon the successful, timely completion of the project. This rating, however, while addressing credit quality subsequent to completion of the project, made no comment on the likelihood of or the risk of default upon failure of such completion.

q: A 'q' subscript indicates that the rating is based solely on quantitative analysis of publicly available information. Discontinued use in April 2001.

r: The 'r' modifier was assigned to securities containing extraordinary risks, particularly market risks, that are not covered in the credit rating. The absence of an 'r' modifier should not be taken as an indication that an obligation would not exhibit extraordinary noncredit-related risks. S&P discontinued the use of the 'r' modifier for most obligations in June 2000 and for the balance of obligations (mainly structured finance transactions) in November 2002.

Fitch Ratings

Long-Term Credit Ratings
Investment Grade

Rated entities in a number of sectors, including financial and non-financial corporations, sovereigns, insurance companies and certain sectors within public finance, are generally assigned Issuer Default Ratings ("IDRs"). IDRs are also assigned to certain entities or enterprises in global infrastructure, project finance and public finance. IDRs opine on an entity's relative vulnerability to default (including by way of a distressed debt exchange) on financial obligations. The threshold default risk addressed by the IDR is generally that of the financial obligations whose non-payment would best reflect the uncured failure of that entity. As such, IDRs also address relative vulnerability to bankruptcy, administrative receivership or similar concepts.

In aggregate, IDRs provide an ordinal ranking of issuers based on the agency's view of their relative vulnerability to default, rather than a prediction of a specific percentage likelihood of default.

AAA: Highest credit quality. 'AAA' ratings denote the lowest expectation of default risk. They are assigned only in cases of exceptionally strong capacity for payment of financial commitments. This capacity is highly unlikely to be adversely affected by foreseeable events.

AA: Very high credit quality. 'AA' ratings denote expectations of very low default risk. They indicate very strong capacity for payment of financial commitments. This capacity is not significantly vulnerable to foreseeable events.

A: High credit quality. 'A' ratings denote expectations of low default risk. The capacity for payment of financial commitments is considered strong. This capacity may, nevertheless, be more vulnerable to adverse business or economic conditions than is the case for higher ratings.

BBB: Good credit quality. 'BBB' ratings indicate that expectations of default risk are currently low. The capacity for payment of financial commitments is considered adequate, but adverse business or economic conditions are more likely to impair this capacity.

Speculative Grade

BB: Speculative. 'BB' ratings indicate an elevated vulnerability to default risk, particularly in the event of adverse changes in business or economic conditions over time; however, business or financial flexibility exists that supports the servicing of financial commitments.

December 2, 2025 (as supplemented January 14, 2026) | Prospectus A-5

PIMCO ETF Trust

B: Highly speculative. 'B' ratings indicate that material default risk is present, but a limited margin of safety remains. Financial commitments are currently being met; however, capacity for continued payment is vulnerable to deterioration in the business and economic environment.

CCC: Substantial credit risk. Very low margin for safety. Default is a real possibility.

CC: Very high levels of credit risk. Default of some kind appears probable.

C: Near default.

A default or default-like process has begun, or for a closed funding vehicle, payment capacity is irrevocably impaired. Conditions that are indicative of a 'C' category rating for an issuer include:

a. the issuer has entered into a grace or cure period following non-payment of a material financial obligation;

b. the formal announcement by the issuer or their agent of a distressed debt exchange;

c. a closed financing vehicle where payment capacity is irrevocably impaired such that it is not expected to pay interest and/or principal in full during the life of the transaction, but where no payment default is imminent.

RD: Restricted default. 'RD' ratings indicate an issuer that in Fitch's opinion has experienced an uncured payment default or distressed debt exchange on a bond, loan or other material financial obligation but has not entered into bankruptcy filings, administration, receivership, liquidation or other formal winding-up procedure, and has not otherwise ceased operating. This would include:

i. the selective payment default on a specific class or currency of debt;

ii. the uncured expiry of any applicable original grace period, cure period or default forbearance period following a payment default on a bank loan, capital markets security or other material financial obligation.

D: Default. 'D' ratings indicate an issuer that in Fitch's opinion has entered into bankruptcy filings, administration, receivership, liquidation or other formal winding-up procedure or that has otherwise ceased business and debt is still outstanding. Default ratings are not assigned prospectively to entities or their obligations; within this context, non-payment on an instrument that contains a deferral feature or grace period will generally not be considered a default until after the expiration of the deferral or grace period, unless a default is otherwise driven by bankruptcy or other similar circumstance, or by a distressed debt exchange.

In all cases, the assignment of a default rating reflects the agency's opinion as to the most appropriate rating category consistent with the rest of its universe of ratings, and may differ from the definition of default under the terms of an issuer's financial obligations or local commercial practice.

The modifiers "+" or "-" may be appended to a rating to denote relative status within major rating categories. For example, the rating category 'AA' has three notch-specific rating levels ('AA+'; 'AA'; 'AA-'; each a rating level). Such suffixes are not added to 'AAA' ratings and ratings below the 'CCC' category.

Recovery Ratings

Recovery Ratings are assigned to selected individual securities and obligations, most frequently for individual obligations of corporate finance issuers with IDRs in speculative grade categories.

Among the factors that affect recovery rates for securities are the collateral, the seniority relative to other obligations in the capital structure (where appropriate), and the expected value of the company or underlying collateral in distress.

The Recovery Rating scale is based on the expected relative recovery characteristics of an obligation upon the curing of a default, emergence from insolvency or following the liquidation or termination of the obligor or its associated collateral.

Recovery Ratings are an ordinal scale and do not attempt to precisely predict a given level of recovery. As a guideline in developing the rating assessments, the agency employs broad theoretical recovery bands in its ratings approach based on historical averages and analytical judgment, but actual recoveries for a given security may deviate materially from historical averages.

RR1: Outstanding recovery prospects given default.'RR1' rated securities have characteristics consistent with securities historically recovering 91%-100% of current principal and related interest.

RR2: Superior recovery prospects given default.'RR2' rated securities have characteristics consistent with securities historically recovering 71%-90% of current principal and related interest.

RR3: Good recovery prospects given default.'RR3' rated securities have characteristics consistent with securities historically recovering 51%-70% of current principal and related interest.

RR4: Average recovery prospects given default.'RR4' rated securities have characteristics consistent with securities historically recovering 31%-50% of current principal and related interest.

RR5: Below average recovery prospects given default.'RR5' rated securities have characteristics consistent with securities historically recovering 11%-30% of current principal and related interest.

RR6: Poor recovery prospects given default.'RR6' rated securities have characteristics consistent with securities historically recovering 0%-10% of current principal and related interest.

Short-Term Credit Ratings

A short-term issuer or obligation rating is based in all cases on the short-term vulnerability to default of the rated entity and relates to the capacity to meet financial obligations in accordance with the documentation governing the relevant obligation. Short-term deposit ratings may be adjusted for loss severity. Short-Term Ratings are assigned to obligations whose initial maturity is viewed as "short term" based on market convention (a long-term rating can also be used to rate

A-6 Prospectus| PIMCO ETF Trust

Prospectus

an issue with short maturity). Typically, this means a timeframe of up to 13 months for corporate, sovereign, and structured obligations, and up to 36 months for obligations in U.S. public finance markets.

F1: Highest short-term credit quality.Indicates the strongest intrinsic capacity for timely payment of financial commitments; may have an added "+" to denote any exceptionally strong credit feature.

F2: Good short-term credit quality.Good intrinsic capacity for timely payment of financial commitments.

F3: Fair short-term credit quality.The intrinsic capacity for timely payment of financial commitments is adequate.

B: Speculative short-term credit quality.Minimal capacity for timely payment of financial commitments, plus heightened vulnerability to near term adverse changes in financial and economic conditions.

C: High short-term default risk.Default is a real possibility.

RD: Restricted default.Indicates an entity that has defaulted on one or more of its financial commitments, although it continues to meet other financial obligations. Typically applicable to entity ratings only.

D: Default.Indicates a broad-based default event for an entity, or the default of a short-term obligation.

For the short-term rating category of 'F1', a '+' may be appended. For VRs, the modifiers "+" or "-" may be appended to a rating to denote relative status within categories from 'aa' to 'ccc'. For Derivative Counterparty Ratings, the modifiers "+" or "-" may be appended to the ratings within 'AA(dcr)' to 'CCC(dcr)' categories.

December 2, 2025 (as supplemented January 14, 2026) | Prospectus A-7

INVESTMENT MANAGER

PIMCO, 650 Newport Center Drive, Newport Beach, CA 92660

DISTRIBUTOR

PIMCO Investments LLC, 1633 Broadway, New York, NY 10019

CUSTODIAN

State Street Bank & Trust Co., 2323 Grand Boulevard, 5th Floor, Kansas City, MO 64108

TRANSFER AGENT

State Street Bank & Trust Co., 2323 Grand Boulevard, 5th Floor, Kansas City, MO 64108

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

PricewaterhouseCoopers LLP, 1100 Walnut Street, Suite 1300, Kansas City, MO 64106

LEGAL COUNSEL

Dechert LLP, 1900 K Street N.W., Washington, D.C. 20006

For further information about the PIMCO ETF Trust, call 1.888.400.4ETF or visit our website at www.pimcoetfs.com.

PIMCO ETF Trust
650 Newport Center Drive
Newport Beach, CA 92660

The Trust's SAI, Form N-CSR and annual and semi-annual reports to shareholders include additional information about the Fund. The SAI is incorporated by reference into this prospectus, which means it is part of this prospectus for legal purposes. The SAI contains detailed information about the Fund's purchase, redemption and exchange options and procedures and other information about the Fund. The Fund's annual report discusses the market conditions and investment strategies that significantly affected the Fund's performance during its last fiscal year. In Form N-CSR, you will find the Fund's annual and semi-annual financial statements.

You may get free copies of any of these materials or request other information about the Fund by calling the Trust at 1.888.400.4ETF (1.888.400.4383), by visiting www.pimcoetfs.com or by writing to:

PIMCO ETF Trust
650 Newport Center Drive
Newport Beach, CA 92660

Reference the Trust's Investment Company Act file number in your correspondence.

Paper copies of the Fund's shareholder reports are required to be provided free of charge by the Fund or financial intermediary upon request. You may access reports and other information about the Trust on the EDGAR Database on the Commission's website at www.sec.gov. You may get copies of additional information about the Trust, including its SAI, with payment of a duplication fee, by e-mailing your request to [email protected]. You can also visit our website at www.pimcoetfs.comfor additional information about the Fund, including the SAI, Form N-CSR, the annual and semi-annual reports to shareholders, and other information such as Fund financial statements, which are available for download free of charge.

Investment Company Act File Number: 811-22250

ETF0008_011426

PIMCO ETF Trust published this content on January 14, 2026, and is solely responsible for the information contained herein. Distributed via EDGAR on January 14, 2026 at 19:26 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]

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