Transamerica Series Trust

04/30/2026 | Press release | Distributed by Public on 04/30/2026 14:11

Summary Prospectus by Investment Company (Form 497K)

Transamerica ProFund UltraBear VP
Summary Prospectus May 1, 2026  
Class
Initial & Service (No Ticker)
This summary prospectus is designed to provide shareholders with key portfolio information in a clear and concise format. Before you invest, you may want to review the portfolio's prospectus, which contains more information about the portfolio and its risks. You can find the portfolio's prospectus, reports to shareholders, and other information about the portfolio, including the portfolio's statement of additional information, online at https://www.transamerica.com/financial-pro/annuities/prospectus. You can also get this information at no cost by calling 866-414-6349 or by sending an e-mail request to [email protected], or from your financial professional. The portfolio's prospectus and statement of additional information, both dated May 1, 2026, as supplemented from time to time, are incorporated by reference into this summary prospectus.
Investment Objective: Seeks daily investment results, before fees and expenses, that correspond to two times the inverse (-2x) of the daily performance of the S&P 500® Index. The portfolio does not seek to achieve its stated objective over a period of time greater than a single day.
Important Information About the Portfolio:
The portfolio seeks investment results for a single day only, not for any other period. The return of the portfolio for periods longer than a single day will be the result of its return for each day compounded over the period. The portfolio's returns for periods longer than a single day will very likely differ in amount and possibly even direction from two times the inverse (-2x) of the return of the S&P 500® Index (the "Index") for that period. For periods longer than a single day, the portfolio will lose money if the Index's performance is flat, and it is possible that the portfolio will lose money even if the level of the Index falls. Longer holding periods, higher index volatility, and inverse exposure each exacerbate the impact of compounding on an investor's returns. During periods of higher Index volatility, the volatility of the Index may affect the portfolio's return as much as or more than the return of the Index.
The portfolio presents different risks than other types of portfolios. The portfolio uses leverage and is riskier than similarly benchmarked funds that do not use leverage. The portfolio may not be suitable for all investors and should be used only by knowledgeable investors who understand the consequences of seeking daily inverse leveraged (-2x) investment results including the impact of compounding on portfolio performance. Investors in the portfolio should actively manage and monitor their investments, as frequently as daily. An investor in the portfolio could potentially lose the full principal value of his/her investment within a single day.
Fees and Expenses: This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the portfolio, but it does not reflect any charges that are, or may be, imposed under your variable life insurance policy or variable annuity contract. If such charges were reflected, fees would be higher.
Shareholder Fees (fees paid directly from your investment) 
Class:
Initial
Service
Maximum sales charge (load) imposed on purchases
(as a percentage of offering price)
None
None
Maximum deferred sales charge (load) (as a
percentage of purchase price or redemption
proceeds, whichever is lower)
None
None
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) 
Class:
Initial
Service
Management fees
0.88%
0.88%
Distribution and service (12b-1) fees
None
0.25%
Other expenses1
0.39%2
0.39%
Total annual fund operating expenses
1.27%
1.52%
Fee waiver and/or expense reimbursement3
0.29%
0.29%
Total annual fund operating expenses after fee
waiver and/or expense reimbursement
0.98%
1.23%
1
Total annual fund operating expenses do not correlate to the ratios of expenses to average net assets in the Financial Highlights table, which include overdraft charges that are considered extraordinary expenses. Had these extraordinary expenses been included, Other Expenses would have been 0.40% for Initial Class and Service Class shares.
2
Other expenses for Initial Class shares are based on estimates for the current fiscal year.
3
Contractual arrangements have been made with the portfolio's investment manager, Transamerica Asset Management, Inc. ("TAM"), through May 1, 2027 to waive fees and/or reimburse portfolio expenses to the extent that the total annual fund operating expenses exceed 0.98% for Initial Class shares and 1.23% for Service Class shares, excluding, as applicable, acquired fund fees and expenses, interest (including borrowing costs and overdraft charges), taxes, brokerage commissions, dividend and interest expenses on securities sold short, extraordinary expenses and other expenses not incurred in the ordinary course of the portfolio's business. These arrangements cannot be terminated prior to May 1, 2027 without the Board of Trustees' consent. TAM is permitted to recapture amounts waived and/or reimbursed to a class during any of the 36 months from the date on which TAM waived fees and/or reimbursed expenses for the class if the class' total annual fund operating expenses have fallen to a level below the limits described above. In no case will TAM recapture any amount that would result, on any particular business day of the portfolio, in the class's total annual operating expenses exceeding the applicable limits described above or any other lower limit then in effect.
Example: This Example is intended to help you compare the cost of investing in the portfolio with the cost of investing in other mutual funds.
The Example assumes that you invest $10,000 in the portfolio for the time periods indicated and then redeem all shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the portfolio's operating expenses
remain the same. The Example does not reflect charges that are, or may be, imposed under your variable life insurance policy or variable annuity contract. If such charges were reflected, costs would be higher. The Example reflects applicable waivers and/or reimbursements for the duration of such arrangement(s). Although your actual costs may be higher or lower, based on these assumptions your costs would be: 
1 year
3 years
5 years
10 years
Initial Class
$100
$374
$669
$1,508
Service Class
$125
$452
$802
$1,788
Portfolio Turnover: The portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual portfolio operating expenses or in the Example, affect the portfolio's performance.
During the most recent fiscal year, the portfolio turnover rate for the portfolio was 0% of the average value of its portfolio.
Derivative instruments and instruments with a maturity of one year or less at the time of acquisition are excluded from the portfolio turnover rate.
Principal Investment Strategies: The portfolio invests in derivatives that the portfolio's sub-adviser, ProFund Advisors LLC (the "sub-adviser"), believes, in combination, should have similar daily return characteristics as twice the inverse (-2x) of the daily return of the Index. Cash balances arising from the use of derivatives will typically be held in money market instruments. The Index is a measure of large-cap U.S. stock market performance. It is a float-adjusted, market capitalization-weighted index of approximately 500 U.S. operating companies and real estate investment trusts selected through a process that factors in criteria such as liquidity, price, market capitalization and financial viability. As of December 31, 2025, the Index included companies with capitalizations between $5.54 billion and $4.53 trillion. The average capitalization of the companies comprising the Index was approximately $121.49 billion. The Index is published under the Bloomberg ticker symbol "SPX."
Derivatives - The portfolio invests in derivatives, which are financial instruments whose value is derived from the value of an underlying asset or assets, such as stocks, bonds or funds (including exchange traded funds ("ETFs")), interest rates or indexes. The portfolio invests in derivatives as a substitute for directly shorting stocks in order to gain inverse leveraged exposure to the Index. These derivatives principally include:
Swap Agreements - Contracts entered into primarily with major global financial institutions for a specified period ranging from one day to more than one year. In a standard "swap" transaction, two parties agree to exchange the return (or differentials in rates of return) earned or realized on particular predetermined investments or instruments. The gross return to be exchanged or "swapped" between the parties is calculated with respect to a "notional amount," (e.g., the return on, or change in value of, a particular dollar amount invested in a "basket" of securities or an ETF representing a particular index).
Futures Contracts - Standardized contracts traded on, or subject to the rules of, an exchange that calls for the future delivery of a specified quantity and type of asset at a specified time and place or, alternatively, may call for cash settlement.
Money Market Instruments - The portfolio invests in short-term cash instruments that have a remaining maturity of 397 days or less and exhibit high quality credit profiles, including:
U.S. Treasury Bills - U.S. government securities that have initial maturities of one year or less, and are supported by the full faith and credit of the U.S. government.
Repurchase Agreements - Contracts in which a seller of securities, usually U.S. government securities or other "highly liquid securities", agrees to buy them back at a specified time and price. Repurchase agreements are primarily used by the portfolio as a short-term investment vehicle for cash positions.
The sub-adviser uses a mathematical approach to investing. Using this approach, the sub-adviser determines the type, quantity and mix of investment positions that the portfolio should hold to approximate, on a daily basis, the performance of twice the inverse (-2x) of the Index. The portfolio may gain inverse exposure to only a representative sample of the securities in the Index, or to securities not continued in the Index or in financial instruments, with the intent of obtaining exposure with aggregate characteristics similar to those of a multiple of the inverse of the Index. The sub-adviser does not invest the assets of the portfolio in securities or derivatives based on the sub-adviser's view of the investment merit of a particular security, instrument, or company, nor does it conduct conventional investment research or analysis, or forecast market movement or trends, in managing the assets of the portfolio. The portfolio seeks to remain fully invested at all times in securities and/or derivatives that, in combination, provide inverse leveraged exposure to the Index without regard to market conditions, trends or direction. The portfolio seeks investment results for a single day, not for longer periods.
On a daily basis, the portfolio will seek to position its portfolio so that its exposure to the Index is consistent with the portfolio's investment objective. The Index's movements during the day will affect whether the portfolio's holdings need to be re-positioned. For example, if the Index has risen on a given day, net assets of the portfolio should fall. As a result, the portfolio's inverse exposure will need to be decreased. Conversely, if the portfolio's Index has fallen on a given day, net assets of the portfolio should rise. As a result, the portfolio's inverse exposure will need to be increased.
Because of daily rebalancing and the compounding of each day's return over time, the return of the portfolio for periods longer than a single day will be the result of each day's returns compounded over the period, which will very likely differ from twice the inverse (-2x) of the return of the Index over the same period. The portfolio will lose money if the level of the Index is flat, and it is possible that the portfolio will lose money even if the level of the Index falls, as a result of daily rebalancing, the Index's volatility and the effects of compounding. See "Principal Risks", below.
The portfolio will concentrate its investments in a particular industry or group of industries to approximately the same extent as the Index is so concentrated.
The portfolio is non-diversified.
Principal Risks: Risk is inherent in all investing. Many factors and risks affect the portfolio's performance, including those described below. The value of your investment in the portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly day to day and over time. You may lose part or all of your investment in the portfolio or your investment may not perform as well as other similar investments. The following is a summary description of principal risks (in alphabetical order after certain key risks) of investing in the portfolio. An investment in the portfolio is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You may lose money if you invest in this portfolio.
Market - The market prices of the portfolio's securities or other assets may go up or down, sometimes rapidly or unpredictably, due to factors such as economic events, inflation, changes in interest rates, governmental actions or interventions, actions taken by the U.S. Federal Reserve or foreign central banks, market disruptions caused by tariffs, trade disputes, labor strikes, supply chain disruptions or other factors, government shutdowns, political developments, civil unrest, acts of terrorism, armed conflicts, economic sanctions, countermeasures in response to sanctions, cybersecurity events, technological developments (such as artificial intelligence and machine learning), investor sentiment, the global and domestic effects of widespread or local health, weather or climate events, and other factors that may or may not be related to the issuer of the security or other asset. The market price of a security may also fall due to specific conditions that affect a particular sector of the securities market, a particular industry or a particular issuer or group of issuers. To the extent that securities of certain issuers behave or are perceived to behave similarly to each other, the market prices of those securities (or the market as a whole) may fall in response to a decline in the price of a particular security or group of securities. If the market prices of the portfolio's securities and assets fall, the value of your investment in the portfolio could go down.
Economies and financial markets throughout the world are increasingly interconnected. Events or circumstances in one or more countries or regions could be highly disruptive to, and have profound impacts on, global economies or markets. As a result, whether or not the portfolio invests in securities of issuers located in or with significant exposure to the countries directly affected, the value and liquidity of the portfolio's investments may go down.
The long-term consequences to the U.S. economy of the continued expansion of U.S. government debt and deficits are not known. Also, raising the ceiling on U.S. government debt and periodic legislation to fund the government have become increasingly politicized. Any failure to do either could lead to a default on U.S. government obligations, with unpredictable consequences for the portfolio's investments, and generally for economies and markets in the U.S. and elsewhere.
Inverse Correlation - Investors will lose money when the Index rises - a result that is the opposite from traditional funds.
Equity and Market - Equity markets are volatile, and the value of securities, swaps, futures and other instruments related to equity markets may fluctuate dramatically from day-to-day. Equity markets are subject to corporate, political, regulatory, market and economic developments, as well as developments that impact specific economic sectors, industries or segments of the market. Further, stocks in the Index may underperform other equity investments. Volatility in the markets and/or market developments may cause the value of an investment in the portfolio to decrease over short or long periods of time. As a portfolio seeking daily investment results, before fees and expenses, that correspond to two times the inverse (-2x) of the daily return of the Index, the value of an investment in the portfolio is expected to decline when market conditions cause the level of the Index to rise.
Leveraging - The portfolio obtains investment exposure in excess of its assets in seeking to achieve its investment objective - a form of leverage - and will lose more money in market environments adverse to its daily objective than a similar fund that does not employ such leverage. The use of leverage could result in the total loss of an investor's investment. For example, because the portfolio includes a multiplier of two times the inverse (-2x) of the Index, a single day movement in the Index approaching 50% at any point in the day could result in the total loss of an investor's investment if that movement is contrary to the investment objective of the portfolio, even if the Index subsequently moves in an opposite direction, eliminating all or a portion of the earlier movement. This would be the case with any such single day movements in the Index, even if the Index maintains a level greater than zero at all times.
Derivatives - The use of derivatives involves a variety of risks, which may be different from, or greater than, the risks associated with investing in traditional securities, such as stocks and bonds. Risks of derivatives include leverage risk, liquidity risk, interest rate risk, valuation risk, market risk, counterparty risk and credit risk. Use of derivatives can increase portfolio losses, increase costs, reduce opportunities for gains, increase portfolio volatility, and not produce the result intended. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Even a small investment in derivatives can have a disproportionate impact on the portfolio. Derivatives may be difficult or impossible to sell, unwind or value, and the counterparty (including, if applicable, the portfolio's clearing broker, the derivatives exchange or the clearinghouse) may default on its obligations to the portfolio. In certain cases, the portfolio may incur costs and may be hindered or delayed in enforcing its rights against or closing out derivatives instruments with a counterparty, which may result in additional losses. Derivatives are also generally subject to the risks applicable to the assets, rates, indices or other indicators underlying the derivative, including market risk, credit risk, liquidity risk, management risk and valuation risk. Also, suitable derivative transactions may not be available in all circumstances or at reasonable prices. The value of a derivative may fluctuate more or less than, or otherwise not correlate well with, the underlying assets, rates, indices or other indicators to which it relates. Using derivatives also subjects the portfolio to certain operational and legal risks. The portfolio may segregate cash or other liquid assets to cover the funding of its
obligations under derivatives contracts or make margin payments when it takes positions in derivatives involving obligations to third parties. Rule 18f-4 under the 1940 Act provides a comprehensive regulatory framework for the use of derivatives by funds and imposes requirements and restrictions on portfolios using derivatives. Rule 18f-4 could have an adverse impact on the portfolio's performance and its ability to implement its investment strategies and may increase costs related to the portfolio's use of derivatives. The rule may affect the availability, liquidity or performance of derivatives, and may not effectively limit the risk of loss from derivatives.
Index Performance - The portfolio is linked to a benchmark maintained by a third party provider that is unaffiliated with the portfolio. There can be no guarantee or assurance that the methodology used by the third party provider to create the benchmark will result in the portfolio achieving high, or even positive, returns. Further, there can be no guarantee that the methodology underlying the benchmark or the daily calculation of the benchmark will be free from error. It is also possible that the value of the benchmark or its underlying reference assets (i.e., the constituent securities of the benchmark) may be subject to intentional manipulation by third-party market participants. The particular benchmark used by the portfolio may underperform other asset classes and may underperform other indices or benchmarks based upon the same underlying reference assets. Each of these factors could have a negative impact on the performance of the portfolio.
Compounding - The portfolio has a single day investment objective, and the portfolio's performance for periods greater than a single day will be the result of each day's returns compounded over the period, which is likely to be either better or worse than the Index performance times the stated multiple in the portfolio's investment objective, before accounting for fees and fund expenses. Compounding affects all investments, but has a more significant impact on an inverse leveraged fund. Particularly during periods of higher Index volatility, compounding will cause results for periods longer than a single day to vary from two times the inverse (-2x) of the return of the Index. This effect becomes more pronounced as volatility increases.
Portfolio performance for periods greater than a single day can be estimated given any set of assumptions for the following factors: a) Index volatility; b) Index performance; c) period of time; d) financing rates associated with inverse leveraged exposure; e) other portfolio expenses; and f) dividends or interest paid with respect to securities in the Index. The chart below illustrates the impact of two principal factors - Index volatility and Index performance - on portfolio performance. The chart shows estimated portfolio returns for a number of combinations of Index volatility and Index performance over a one-year period. Performance shown in the chart assumes: (a) no dividends paid with respect to securities included in the Index; (b) no portfolio expenses; and (c) borrowing/lending rates (to obtain inverse leveraged exposure) of zero percent. If portfolio expenses and/or actual borrowing/lending rates were reflected, the portfolio's performance would be different than shown.
Areas shaded darker represent those scenarios where the portfolio can be expected to return less than two times the inverse (-2x) of the performance of the Index.
Estimated Portfolio Returns  
Performance
Volatility Rate
One
Year
Index
-2x One
Year
Index
10%
25%
50%
75%
100%
-60%
120%
506.5%
418.1%
195.2%
15.6%
-68.9%
-50%
100%
288.2%
231.6%
88.9%
-26.0%
-80.1%
-40%
80%
169.6%
130.3%
31.2%
-48.6%
-86.2%
-30%
60%
98.1%
69.2%
-3.6%
-62.2%
-89.8%
-20%
40%
51.6%
29.5%
-26.2%
-71.1%
-92.2%
-10%
20%
19.8%
2.3%
-41.7%
-77.2%
-93.9%
0%
0%
-3.0%
-17.1%
-52.8%
-81.5%
-95.0%
10%
-20%
-19.8%
-31.5%
-61.0%
-84.7%
-95.9%
20%
-40%
-32.6%
-42.4%
-67.2%
-87.2%
-96.5%
30%
-60%
-42.6%
-50.9%
-72.0%
-89.1%
-97.1%
40%
-80%
-50.5%
-57.7%
-75.9%
-90.6%
-97.5%
50%
-100%
-56.9%
-63.2%
-79.0%
-91.8%
-97.8%
60%
-120%
-62.1%
-67.6%
-81.5%
-92.8%
-98.1%
The foregoing table is intended to isolate the effect of Index volatility and Index performance on the return of the portfolio. For example, the portfolio may incorrectly be expected to achieve a -40% return on a yearly basis if the Index return were 20%, absent the effects of compounding. However, as the table shows, with Index volatility of 50%, the portfolio could be expected to return -67.2% under such a scenario. The portfolio's actual returns may be significantly better or worse than the returns shown above as a result of any number of factors, including those discussed in "Principal Risks - Correlation" below.
The Index's annualized historical volatility rate for the five-year period ended December 31, 2025 was 16.97%. The Index's highest December to December volatility rate during the five-year period was 24.18% (December 31, 2022). The Index's annualized total return performance for the five-year period ended December 31, 2025 was 14.42%.
Historical Index volatility and performance are not indications of what the Index volatility and performance will be in the future. The volatility of U.S. exchange-traded securities or instruments that reflect the value of the Index may differ from the volatility of the Index.
Counterparty - The portfolio could lose money if the counterparties to derivatives, repurchase agreements and/or other financial contracts entered into for the portfolio do not fulfill their contractual obligations. In addition, the portfolio may incur costs and may be hindered or delayed in enforcing its rights against a counterparty. These risks may be greater to the extent the portfolio has more contractual exposure to a counterparty.
Industry Concentration - The portfolio will concentrate its investments in issuers of one or more particular industries to the same extent that its underlying index is so concentrated and to the extent permitted by applicable regulatory guidance. Concentration
in a particular industry heightens the risks associated with that industry. As a result, the portfolio may be subject to greater price volatility and risk of loss as a result of adverse economic, business or other developments affecting that industry than portfolios investing in a broader range of industries.
Non-Diversification - As a "non-diversified" portfolio, the portfolio may invest a larger percentage of its assets in a smaller number of issuers than a diversified fund. Investing in a smaller number of issuers will make the portfolio more susceptible to the risks associated with investing in those issuers.
Management - The value of your investment may go down if the investment manager's or sub-adviser's judgments and decisions are incorrect or otherwise do not produce the desired results, or if the investment strategy does not work as intended. You may also suffer losses if there are imperfections, errors or limitations in the quantitative, analytic or other tools, resources, information and data used, investment techniques applied, or the analyses employed or relied on, by the investment manager or sub-adviser, if such tools, resources, information or data are used incorrectly or otherwise do not work as intended, or if the investment manager's or sub-adviser's investment style is out of favor or otherwise fails to produce the desired results. Any of these things could cause the portfolio to lose value or its results to lag relevant benchmarks or other funds with similar objectives.
Active Trading - The portfolio may engage in active trading of its portfolio. Active trading will increase transaction costs and could detract from performance. Active trading may be more pronounced during periods of market volatility.
CFTC Regulation - The Investment Manager has registered as a "commodity pool operator" under the Commodity Exchange Act with respect to its service as investment manager to the portfolio. The Investment Manager is therefore subject to dual regulation by the SEC and the Commodity Futures Trading Commission ("CFTC"), and is a member of the National Futures Association and is also subject to its rules and oversight. Regulation of commodity investing continues to change, and additional compliance and other expenses may be incurred.
Correlation - A number of factors may affect the portfolio's ability to achieve a high degree of inverse correlation with the Index, and there is no guarantee that the portfolio will achieve a high degree of inverse correlation. Failure to achieve a high degree of inverse correlation may prevent the portfolio from achieving its investment objective, and the percentage share of the portfolio's net asset value each day may differ, perhaps significantly in amount, and possibly even direction, from two times the inverse (-2x) of the percentage change of the Index on such day.
In order to achieve a high degree of inverse correlation with the Index, the portfolio seeks to rebalance its portfolio daily to keep exposure consistent with its investment objective. Being materially over- or underexposed to the Index may prevent the portfolio from achieving a high degree of inverse correlation with the Index. Market disruptions or closure, regulatory restrictions, extreme market volatility and other factors will adversely affect the portfolio's ability to adjust exposure to requisite levels. The target amount of portfolio exposure is impacted dynamically by the Index's movements. Because of this, it is unlikely that the portfolio will have perfect inverse leveraged (-2x) exposure to the
Index at the end of each day and the likelihood of being materially over- or underexposed is higher on days when the Index level is volatile at or near the close of the trading day.
A number of other factors may also adversely affect the portfolio's inverse correlation with the Index, including fees, expenses, transaction costs, financing costs associated with the use of derivatives, income items, valuation methodology, accounting standards and disruptions or illiquidity in the markets for the securities or financial instruments in which the portfolio invests. The portfolio may not have investment exposure to all securities in the Index, or its weighting of investment exposure to securities may be different from that of the Index. In addition, the portfolio may invest in securities not included in the Index. The portfolio may take or refrain from taking positions in order to improve tax efficiency, or comply with regulatory restrictions, either of which may negatively affect the portfolio's correlation with the Index. The portfolio may also be subject to large movements of assets into and out of the portfolio, potentially resulting in the portfolio being over- or underexposed to the Index and may be impacted by Index reconstitutions and Index rebalancing events. Any of these factors could decrease correlation between the performance of the portfolio and the Index and may hinder the portfolio's ability to meet its investment objective.
Credit - If an issuer or other obligor (such as a party providing insurance or other credit enhancement) of a security held by the portfolio or a counterparty to a financial contract with the portfolio is unable or unwilling to meet its financial obligations, or is downgraded or perceived to be less creditworthy (whether by market participants, ratings agencies, pricing services or otherwise), or if the value of any underlying assets declines, the value of your investment will typically decline. A decline may be rapid and/or significant, particularly in certain market environments. In addition, the portfolio may incur costs and may be hindered or delayed in enforcing its rights against an issuer, obligor or counterparty.
Cybersecurity - Cybersecurity incidents, both intentional and unintentional, may allow an unauthorized party to gain access to portfolio assets, portfolio or shareholder data (including private shareholder information), or proprietary information, cause the portfolio or its service providers (including, but not limited to, the portfolio's investment manager, any sub-adviser(s), transfer agent, distributor, custodian, fund accounting agent and financial intermediaries) to suffer data breaches, data corruption or loss of operational functionality, or prevent portfolio investors from purchasing, redeeming or exchanging shares, receiving distributions or receiving timely information regarding the portfolio or their investment in the portfolio. Cybersecurity incidents may render records of portfolio assets and transactions, shareholder ownership of portfolio shares, and other data integral to the functioning of the portfolio inaccessible, inaccurate or incomplete. The use of artificial intelligence and machine learning could exacerbate these risks. Cybersecurity incidents may result in financial losses to the portfolio and its shareholders, and substantial costs may be incurred in order to prevent or mitigate any future cybersecurity incidents.
Early Close/Late Close/Trading Halt - An exchange or market may close early, close late or issue trading halts generally or on financial instruments, the ability to trade certain financial instruments may be restricted, which may result in the portfolio being unable to trade those and other related financial instruments.
In these circumstances, the portfolio may be unable to rebalance its portfolio, may be unable to accurately price its investments and/or may incur substantial trading losses.
Extension - When interest rates rise, payments of fixed-income securities, including asset- and mortgage-backed securities, may occur more slowly than anticipated, causing their market prices to decline.
Fixed-Income Securities - Risks of fixed-income securities include credit risk, interest rate risk, counterparty risk, prepayment risk, extension risk, valuation risk, and liquidity risk. The value of fixed-income securities may go up or down, sometimes rapidly and unpredictably, due to general market conditions, such as real or perceived adverse economic or political conditions, tariffs and trade disruptions, wars, social unrest, inflation, changes in interest rates, lack of liquidity in the bond markets or adverse investor sentiment. In addition, the value of a fixed-income security may decline if the issuer or other obligor of the security fails to pay principal and/or interest, otherwise defaults or has its credit rating downgraded or is perceived to be less creditworthy, or the credit quality or value of any underlying assets declines. If the value of fixed-income securities owned by the portfolio falls, the value of your investment will go down. The portfolio may lose its entire investment in the fixed-income securities of an issuer.
Interest Rate -The value of fixed-income securities generally goes down when interest rates rise. A rise in rates tends to have a greater impact on the prices of longer term or duration securities. Changes in interest rates can be sudden and unpredictable and may expose the markets to significant volatility, which also may affect the liquidity of the portfolio's investments and detract from portfolio performance. A variety of factors can impact interest rates, including central bank monetary policies and inflation rates. A general rise in interest rates may cause investors to sell fixed-income securities on a large scale, which could adversely affect the price and liquidity of fixed-income securities generally and could also result in increased redemptions from the portfolio. Increased redemptions could cause the portfolio to sell securities at inopportune times or depressed prices and result in further losses. Inflation and interest rates have been volatile and may increase in the future. Interest rate increases in the future may cause the value of fixed-income securities to decrease and, conversely, interest rate reductions may cause the value of fixed-income securities to increase.
Large Capitalization Companies - The portfolio's investments in larger, more established companies may underperform other segments of the market because they may be less responsive to competitive challenges and opportunities and unable to attain high growth rates during periods of economic expansion.
Large Shareholder - A significant portion of the portfolio's shares may be owned by one or more investment vehicles or institutional investors. Transactions by these large shareholders may be disruptive to the management of the portfolio. For example, the portfolio may experience large redemptions and could be required to sell securities at a time when it may not otherwise desire to do so. Such transactions may increase the portfolio's brokerage and/or other transaction costs. In addition, sizeable redemptions could cause the portfolio's total expenses to increase.
Liquidity - The portfolio may make investments that are illiquid or that become illiquid after purchase. Illiquid investments can be difficult to value, may trade at a discount from comparable,
more liquid investments, and may be subject to wide fluctuations in value. Liquidity risk may be magnified in rising interest rate or volatile environments. If the portfolio is forced to sell an illiquid investment to meet redemption requests or other cash needs, the portfolio may be forced to sell at a substantial loss or may not be able to sell at all. Liquidity of particular investments, or even entire asset classes, including U.S. Treasury securities, can deteriorate rapidly, particularly during times of market turmoil, and those investments may be difficult or impossible for the portfolio to sell. This may prevent the portfolio from limiting losses.
Portfolio Turnover - The portfolio may incur high portfolio turnover to manage the portfolio's investment exposure. Also, active trading of the portfolio's shares may cause more frequent purchase and sales activities that could, in certain circumstances, increase the number of portfolio transactions. High levels of transactions increase brokerage and other transaction costs and may result in increased taxable capital gains. Each of these factors could have a negative impact on the performance of the portfolio. The portfolio's portfolio turnover rate may vary from year to year, as well as within a year.
Prepayment or Call - Many issuers have a right to prepay their fixed-income securities. If this happens, the portfolio will not benefit from the rise in the market price of the securities that normally accompanies a decline in interest rates and may be forced to reinvest the prepayment proceeds in securities with lower yields.
Repurchase Agreements - In a repurchase agreement, the portfolio purchases securities from a broker-dealer or a bank, called the counterparty, upon the agreement of the counterparty to repurchase the securities from the portfolio at a later date, and at a specified price. The securities purchased serve as the portfolio's collateral for the obligation of the counterparty to repurchase the securities. If the counterparty does not repurchase the securities, the portfolio is entitled to sell the securities, but the portfolio may not be able to sell them for the price at which they were purchased, thus causing a loss. If the counterparty becomes insolvent, there is some risk that the portfolio will not have a right to the securities, or the immediate right to sell the securities.
Short Sale Exposure - The portfolio may seek short exposure through financial instruments which would cause the portfolio to be exposed to certain risks associated with selling short. These risks include, under certain market conditions, an increase in the volatility and decrease in the liquidity of the instruments underlying the short position, which may adversely impact the portfolio's return, result in a loss, have the effect of limiting the portfolio's ability to obtain short exposure through financial instruments, or require the portfolio to seek short exposure through alternative investment strategies that may be less desirable or may be costly to implement. To the extent that, at any particular point in time, the instruments underlying the short position may be thinly traded or have a limited market, including due to regulatory action, the portfolio may be unable to meet its investment objective (e.g., due to a lack of a counterparty or counterparties). Obtaining short exposure through these instruments may be considered an aggressive investment technique.
Underlying Exchange-Traded Funds - To the extent the portfolio invests its assets in underlying ETFs, its ability to achieve its investment objective will depend in part on the performance of the underlying ETFs in which it invests. Investing in underlying
ETFs subjects the portfolio to the risks of investing in the underlying securities or assets held by those ETFs. Each of the underlying ETFs in which the portfolio may invest has its own investment risks, and those risks can affect the value of the underlying ETFs' shares and therefore the value of the portfolio's investments. There can be no assurance that the investment objective of any underlying ETF will be achieved. To the extent that the portfolio invests more of its assets in one underlying ETF than in another, the portfolio will have greater exposure to the risks of that underlying ETF. In addition, the portfolio will bear a pro rata portion of the operating expenses of the underlying ETFs in which it invests.
Valuation - Certain investments may be more difficult to value than other types of investments. The sales price the portfolio could receive for any particular portfolio investment may differ from the portfolio's valuation of the investment, particularly for securities that trade in thin or volatile markets, that are priced based upon valuations provided by third party pricing services, or that are valued using a fair value methodology. These differences may increase significantly and affect portfolio investments more broadly during periods of market volatility. Investors who purchase or redeem portfolio shares on days when the portfolio is holding fair-valued securities may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the portfolio had not fair-valued securities or had used a different valuation methodology. The portfolio's ability to value its investments may also be impacted by technological issues and/or errors by pricing services or other third party service providers. Fair value pricing involves subjective judgment, which may prove to be incorrect.
Performance: The bar chart and the table below provide some indication of the risks of investing in the portfolio. The bar chart shows how the portfolio's performance has varied from year to year. The table shows how the portfolio's average annual total returns for different periods compare to the returns of a broad measure of market performance.
Performance information for Initial Class shares will be included after the share class has been in operation for one complete calendar year.
The performance calculations do not reflect any charges that are, or may be, imposed under your variable life insurance policy or variable annuity contract. If such charges were reflected, performance would be lower.
Absent any applicable fee waivers and/or expense limitations, performance would be lower.
As with all mutual funds, past performance is not a prediction of future results. Updated performance information is available on our website at www.transamerica.com/annuities-performance-center or by calling 1-800-851-9777.
Annual Total Returns (calendar years ended December 31) - Service Class
  
Quarter Ended
Return
Best Quarter:
6/30/2022
34.96%
Worst Quarter:
6/30/2020
-36.36%
Average Annual Total Returns (periods ended December 31, 2025) 
1 Year
5 Years
10 Years
Inception
Date
Service Class
-27.61%
-23.71%
-27.92%
5/1/2009
S&P 500® Index (reflects no
deduction for fees, expenses or
taxes)
17.88%
14.42%
14.82%
Management: 
Investment Manager: Transamerica Asset Management, Inc.
Sub-Adviser: ProFund Advisors LLC
Portfolio Managers:
Michael Neches
Senior Portfolio Manager
since September 2013
Devin Sullivan
Portfolio Manager
since March 2018
Purchase and Sale of Portfolio Shares: Shares of the portfolio may only be purchased or redeemed through variable life insurance policies and variable annuity contracts offered by the separate accounts of participating life insurance companies. Please refer to the corresponding prospectus of the policy or annuity contract that you have chosen for more information about the terms of the offering.
The portfolio does not have any initial or subsequent investment minimums. However, your insurance company may impose investment minimums.
The portfolio will not be charged and does not intend to pay any 12b-1 fees on Initial Class shares through May 1, 2027. The maximum 12b-1 fee on Initial Class shares is 0.15%. The portfolio reserves the right to pay such fees after that date.
The portfolio does not currently offer Initial Class shares.
Tax Information: Distributions made by the portfolio to an insurance company separate account, and exchanges and redemptions of portfolio shares made by the separate account, ordinarily do not cause the owners of insurance policies and annuity contracts invested in the separate account to recognize income or gain for federal income tax purposes. Please refer to the corresponding prospectus of the policy or annuity contract that you have chosen for more information regarding the tax consequences of your investment.
Payments to Broker-Dealers and Other Financial Intermediaries: The portfolio is generally only available as an underlying investment option for separate accounts of Transamerica life insurance companies to fund benefits under variable life insurance policies and variable annuity contracts. The portfolio and/or its affiliates may make payments to a Transamerica insurance company (or its affiliates) and to broker-dealers and other financial intermediaries for the sale of variable contracts (and thus, indirectly, the portfolio's shares) and related services. These payments may create a conflict of interest by influencing the Transamerica insurance company or other intermediary to recommend the variable contracts that invest in the portfolio. Ask your salesperson or visit your financial intermediary's website for more information.
In an effort to reduce paper mailings and conserve natural resources, we encourage you to visit our website, www.transamerica.com, to set up an account and enroll in eDelivery.
SPST0526PFUB
Transamerica Series Trust published this content on April 30, 2026, and is solely responsible for the information contained herein. Distributed via EDGAR on April 30, 2026 at 20:16 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]