Summary Prospectus by Investment Company (Form 497K)

Calvert Emerging Markets Advancement Fund

This Summary Prospectus is designed to provide investors with key fund information in a clear and concise format. Before you invest, you may want to review the Fund's Prospectus and Statement of Additional Information, which contain more information about the Fund and its risks. The Fund's Prospectus and Statement of Additional Information, both dated February 1, 2026, as may be amended or supplemented, are incorporated by reference into this Summary Prospectus. For free paper or electronic copies of the Fund's Prospectus, Statement of Additional Information, annual and semi-annual shareholder reports, and other information about the Fund, go to  http://www.calvert.com/prospectus, email a request to [email protected], call 1-800-368-2745, or ask any financial advisor, bank, or broker-dealer who offers shares of the Fund. Unless otherwise noted, page number references refer to the current Prospectus for this Fund.

Investment Objective

The Fund's investment objective is total return.

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. Investors may also pay commissions or other fees to their financial intermediary, which are not reflected below. You may qualify for a reduced sales charge on purchases of Class A shares if you invest, or agree to invest over a 13-month period, at least $50,000 in Calvert  funds. Certain financial intermediaries also may offer variations in Fund sales charges to their customers as described in Appendix B - Financial Intermediary Sales Charge Variations in the Fund's Prospectus. More information about these and other discounts is available from your financial intermediary and in Sales Charges beginning on page 64 of the Fund's Prospectus and page 24  of the Fund's Statement of Additional Information.

Shareholder Fees (fees paid directly from your investment)

Calvert Emerging Markets Advancement Fund   | Fund Summary

Calvert Emerging Markets Advancement Fund (Con't)

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

Example. This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.  The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, that the operating expenses remain the same and that any expense reimbursement arrangement remains in place for the contractual period. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Portfolio Turnover

The  Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" the 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 Annual Fund Operating Expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 119%  of the average value of its portfolio.

Principal Investment Strategies

Under normal market conditions, the Fund will invest at least 80% of its net assets (plus any borrowings for investment purposes) in equity securities issued by companies located in emerging market countries. Companies located in emerging market countries are defined as those companies tied economically to countries included in the Calvert Emerging Markets Responsible Index (the "Index") (described below).

Equity securities held by the Fund will primarily include common stock, preferred stock, depositary receipts and equity-equivalent securities, such as participation notes ("P-Notes"). The Fund may invest in securities issued by companies with a broad range of market capitalization, including smaller companies. The Fund may also invest in real estate investment trusts ("REITs"). The Fund may purchase and sell derivative instruments, including, but not limited to, futures and forward foreign currency exchange contracts.

The Fund may engage in derivative transactions to hedge against fluctuations in securities prices or currency exchange rates, or as a substitute for the purchase or sale of securities or currencies. The Fund may also lend its securities.

The Fund seeks to employ a top-down investment process based on macroeconomic and governance assessments at the country level. In managing the Fund, the investment adviser seeks to gain exposure to countries with the following characteristics: political and economic conditions that suggest an improving governance and investment climate and/or adoption of policies or other actions that the investment adviser believes will result in increased corporate cash flow and/or reduced discount rates. Security selection within each country generally will be based on the constituents of the Index. The Fund generally intends to hold Index constituents, located in countries selected for investment, in scale to match the proportional security weight of such constituent within the Index. The Fund may invest up to 35% of its total assets in securities of companies whose business activities are in the same industry, to the extent that such industry accounts for more than 15% of the Fund's primary benchmark.

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Calvert Emerging Markets Advancement Fund |  Fund Summary

Calvert Emerging Markets Advancement Fund (Con't)

In addition to meeting certain capitalization and trading requirements, constituents of the Index must meet the environmental, social and governance ("ESG") factors discussed below. The Fund may also invest in securities outside of the Index to broaden its exposure to countries included in the Index and to seek exposure to countries not included in the Index. Such non-Index securities will meet the Index's ESG criteria. The investment adviser will pursue engagement opportunities across the portfolio with both company management and government officials to seek to advance ESG change from the bottom-up stock level and from the top-down at a country level.

Calvert Emerging Markets Responsible Index. The Index is a proprietary index of  CRM, the Fund's investment adviser. Christopher Madden, CFA, Co-Head of Applied Responsible Investment Solutions, and Zi Ye, Index Manager, manage the Index construction process. The Index is composed of equity securities of up to the 1,000 largest companies by market capitalization that are listed on certain global stock exchanges and issued by publicly traded companies located in or tied economically to countries that CRM has classified as emerging markets. Determinations as to whether an equity security represents a company located in or tied economically to an emerging market is based on an assessment of headquarters location, country of incorporation, primary exchange, and country of greatest revenue. CRM determines emerging market countries based on a set of criteria including level of economic development, existence of capital controls, openness to foreign direct investment, market trading and liquidity conditions, regulatory environment, treatment of minority shareholders, and investor expectations. For information about which countries CRM has currently classified as emerging markets for purposes of the Index, please see Calvert's Country Classification, which can be found here: https://www.calvert.com/media/public/43707.pdf.

The Index universe excludes business development companies and equity securities listed less than six months from the last business day of the month preceding reconstitution. Additionally, companies that are included in the Index universe must meet certain capitalization and trading requirements.

Calvert then selects Index components that operate their businesses in a manner that is consistent with the Calvert Principles for Responsible Investing (the "Principles"). The Principles serve as a framework for considering ESG factors (a copy of which is included as an appendix to the Fund's prospectus).  CRM's Index Committee may determine to exclude from the Index a company that operates its business in a manner consistent with the Principles, but has been determined by CRM's Index Committee to have exposure to a product and/or environmental factor believed to present significant health or environmental risks. Companies selected for inclusion in the Index are then weighted by CRM based on market capitalization, and by a combination of country and sector.

The Index is  rebalanced quarterly on the third Friday of the last month of each calendar quarter and reconstituted annually on the third Friday of June.  

Principal Risks

Market Risk. The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund's investments cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility.

Equity Securities Risk. The value of equity securities and related instruments may decline in response to adverse changes in the economy or the economic outlook; deterioration in investor sentiment; interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer and sector-specific considerations; unexpected trading activity among retail investors; or other factors. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines in value, the value of the Fund's equity securities will also likely decline. Although prices can rebound, there is no assurance that values will return to previous levels.

Foreign Investment Risk. Foreign investments can be adversely affected by political, economic and market developments abroad, including the imposition of economic and other sanctions by the United States or another country against a particular country or countries, organizations, entities and/or individuals. There may be less publicly available information about foreign issuers because they may not be subject to reporting practices, requirements or regulations comparable to those to which United States companies are subject. Adverse changes in investment regulations, capital requirements or exchange controls could adversely affect the value of the Fund's investments. Foreign markets may be smaller, less liquid and more volatile than the major markets in the United States and, as a result, Fund share values may be more volatile. Trading in foreign markets typically involves higher expense than trading in the United States. The Fund may have difficulties enforcing its legal or contractual rights in a foreign country. Depositary receipts are subject to many of the risks associated with investing directly in foreign instruments, including the political and economic risks of the underlying issuer's country and, in the case of depositary receipts traded on foreign markets, currency risk.

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Calvert Emerging Markets Advancement Fund   | Fund Summary

Calvert Emerging Markets Advancement Fund (Con't)

Emerging Markets Investment Risk. Investment markets within emerging market countries are typically smaller, less liquid, less developed and more volatile than those in more developed markets like the United States, and may be focused in certain sectors. Emerging market securities often involve greater risks than developed market securities. The information available about an emerging market issuer may be less reliable than for comparable issuers in more developed capital markets.

Currency Risk. Exchange rates for currencies fluctuate daily. The value of foreign investments may be affected favorably or unfavorably by changes in currency exchange rates in relation to the  U.S. dollar. Currency markets generally are not as regulated as securities markets and currency transactions are subject to settlement, custodial and other operational risks.

Focused Investment Risk. To the extent the Fund has substantial investments in a relatively small number of securities or issuers, or a particular market, industry, group of industries, country, region, group of countries, asset class or sector, the Fund's performance will be more susceptible to any single economic, market, political, or regulatory occurrence affecting those particular securities or issuers or that particular market, industry, group of industries, country, region, group of countries, assets class, or sector than a fund that invests more broadly.

Geographic Risk. Because the Fund may invest significantly in a particular geographic region or country, the value of Fund shares may be affected by events that adversely affect that region or country and may fluctuate more than that of a fund that invests more broadly.

Financials Sector Risk. To the extent the Fund invests a substantial portion of its assets in the financials sector, factors that have an adverse impact on this sector may have a disproportionate impact on the Fund's performance. The financials sector can be affected by global and local economic conditions, such as the levels and liquidity of the global and local financial and asset markets, the absolute and relative level and volatility of interest rates and equity prices, investor sentiment, inflation, and the availability and cost of credit. The enactment of new legislation or regulations, as well as changes in interpretation and enforcement of current laws, may affect the manner of operations and profitability of the financials sector.

Smaller and Mid-Sized Company Risk. The stocks of smaller and mid-sized companies are generally subject to greater price fluctuations, limited liquidity, higher transaction costs and higher investment risk than the stocks of larger, more established companies. Such companies may have limited product lines, markets or financial resources, may be dependent on a limited management group, and may lack substantial capital reserves or an established performance record. There may be generally less publicly available information about such companies than for larger, more established companies. Stocks of these companies frequently have lower trading volumes making them more volatile and potentially less liquid and more difficult to value.

Industry Concentration Risk. Because the Fund may invest a significant portion of its assets in one or more industries, the value of Fund shares may be affected by events that adversely affect a particular industry and may fluctuate more than that of a fund that invests more broadly.

Banking Industry Risk. To the extent the Fund invests a substantial portion of its assets in the banking industry, factors that have an adverse impact on this industry may have a disproportionate impact on the Fund's performance. Companies in the banking industry are subject to extensive government regulation and can be significantly affected by the availability and cost of capital funds, changes in interest rates, the rate of corporate and consumer debt defaults, and price competition.

Liquidity Risk. The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices. Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund's performance. These effects may be exacerbated during times of financial or political stress.

Derivatives Risk. The Fund's exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. The use of derivatives can lead to losses because of adverse movements in the price or value of the security, instrument, index, currency, commodity, economic indicator or event underlying a derivative ("reference instrument"), due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create leverage in the Fund, which represents a non-cash exposure to the underlying reference instrument. Leverage can increase both the risk and return potential of the Fund. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund. Use of derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying reference instrument. Derivative instruments traded in over-the-counter markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying reference instrument. If a derivative's  counterparty is unable to honor its commitments, the value of Fund shares may decline and the Fund could experience delays in (or be unable to achieve) the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment. A derivative investment also involves the risks relating to the reference instrument underlying the investment.

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Calvert Emerging Markets Advancement Fund |  Fund Summary

Calvert Emerging Markets Advancement Fund (Con't)

Preferred Stock Risk. Although preferred stocks represent an ownership interest in an issuer, preferred stocks generally do not have voting rights or have limited voting rights and have economic characteristics similar to fixed-income securities. Preferred stocks are subject to issuer-specific risks generally applicable to equity securities and credit and interest rate risks generally applicable to fixed-income securities. The value of preferred stock generally declines when interest rates rise and may react more significantly than bonds and other debt instruments to actual or perceived changes in the company's financial condition or prospects.

Participation Note Risk. Participation notes ("P-Notes") are subject to the risks normally associated with a direct investment in the foreign securities underlying the P-Notes. As the purchaser of a P-Note, the Fund is relying on the creditworthiness of the counterparty issuing the P-Note and does not have the same rights under the P-Note as it would as the owner of the underlying security. If the counterparty becomes insolvent, the Fund could lose the total value of its investment in the P-Note. In addition, there is no assurance that there will be a trading market for a P-Note or that the trading price of a P-Note will equal the value of the underlying security.

Real Estate Risk. Real estate investments are subject to risks associated with owning real estate, including declines in real estate values, increases in property taxes, fluctuations in interest rates, limited availability of mortgage financing, decreases in revenues from underlying real estate assets, declines in occupancy rates, changes in government regulations affecting zoning, land use, and rents, environmental liabilities, and risks related to the management skill and creditworthiness of the issuer. Companies in the real estate industry may also be subject to liabilities under environmental and hazardous waste laws, among others. REITs  must satisfy specific requirements for favorable tax treatment and can involve unique risks in addition to the risks generally affecting the real estate industry. Changes in underlying real estate values may have an exaggerated effect to the extent that investments are concentrated in particular geographic regions or property types.

Securities Lending Risk. Securities lending involves the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund also may lose rights in the collateral if the borrower fails financially. The Fund could also lose money if the value of the collateral decreases or if the value of any investments made with cash collateral declines.

Risks Associated with Active Management and Index Strategy. The portfolio manager employs an active management strategy when selecting countries for investment. The success of this country allocation strategy depends on portfolio management's successful application of analytical skills and investment judgment. Active management involves subjective decisions.

The portfolio manager also uses an index strategy for security selection. The Fund generally expects to hold each Index constituent, located in countries selected for investment, regardless of the Index constituent's current or projected performance. Maintaining investments regardless of market conditions or the performance of individual investments could cause the Fund's return to be lower than if the Fund employed an active strategy with respect to security selection. Unusual market events may increase market volatility and may cause the characteristics of the Index components to vary from those expected under normal circumstances. From time to time, certain Index constituents located in markets selected for investment may not be held by the Fund due to market constraints.

Responsible Investing Risk.  Investing primarily in responsible investments carries the risk that, under certain market conditions, the Fund's performance may be impacted. The application of responsible investment criteria may affect the Fund's exposure to certain sectors or types of investments, and may impact the Fund's relative investment performance depending on whether such sectors or investments are in or out of favor in the market. An investment's  ESG performance or the investment adviser's assessment of such performance may change over time, which could cause the Fund to temporarily hold securities that do not comply with the Fund's responsible investment criteria. In evaluating an investment, the investment adviser is  dependent upon information and data that may be incomplete, inaccurate or unavailable, which could adversely affect the analysis of the ESG factors relevant to a particular investment. Successful application of the Fund's responsible investment strategy will depend on the investment adviser's  skill in properly identifying and analyzing material ESG issues.

General Fund Investing Risks. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objective. It is possible to lose money by investing in the Fund. The Fund is designed to be a long-term investment vehicle and is not suited for short-term trading. Investors in the Fund should have a long-term investment perspective and be able to tolerate potentially sharp declines in value. Purchase and redemption activities by Fund shareholders may impact the management of the Fund and its ability to achieve its investment objective(s). In addition, the redemption by one or more large shareholders or groups of shareholders of their holdings in the Fund could have an adverse impact on the remaining shareholders in the Fund. The Fund relies on various service providers, including the investment adviser and sub-adviser, if applicable, in its operations and is susceptible to operational, information security and related events (such as public health crises, cyber or hacking attacks) that may affect the service providers or the services that they provide to the Fund. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

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Calvert Emerging Markets Advancement Fund   | Fund Summary

Calvert Emerging Markets Advancement Fund (Con't)

Performance

The following bar chart and table provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and how the Fund's average annual returns over time compare with those of a broad-based securities market index and a more narrow proprietary index. The returns in the bar chart are for Class A shares and do not reflect a sales charge. If the sales charge was reflected, the returns would be lower. Past performance (both before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The Fund's performance reflects the effects of expense reductions. Absent these reductions, performance would have been lower. Updated Fund performance information can be obtained by visiting www.calvert.com.

During the period shown in the bar chart above:

Average Annual Total Return (for the calendar periods ended December 31, 2025)

These returns reflect the maximum current sales charge for Class A (5.25%). Class A and Class I commenced operations on October 1, 2019. Investors cannot invest directly in an Index.

Source for  MSCI Emerging Markets Index: MSCI. MSCI data may not be reproduced or used for any other purpose.  MSCI provides no warranties, has not prepared or approved this report, and has no liability hereunder.  

After-tax returns are calculated using the highest historical individual U.S. federal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on a shareholder's tax situation and the actual characterization of distributions, and may differ from those shown. After-tax returns are not relevant to shareholders who hold shares in tax-deferred accounts or to shares held by non-taxable entities. After-tax returns for other Classes of shares will vary from the after-tax returns presented for Class A shares.  Return After Taxes on Distributions for a period may be the same as Return Before Taxes for that period because no taxable distributions were made during that period. Also, Return After Taxes on Distributions and Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or Return After Taxes on Distributions for the same period because of losses realized on the sale of Fund shares.

Management

Investment Adviser. Calvert Research and Management ("CRM" or the "Adviser").

Investment Sub-Adviser. Eaton Vance Advisers International Ltd. ("EVAIL").

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Calvert Emerging Markets Advancement Fund |  Fund Summary

Calvert Emerging Markets Advancement Fund (Con't)

Portfolio Managers

Purchase and Sale of Fund Shares

You may purchase, redeem or exchange Fund shares on any business day, which is any day the New York Stock Exchange is open for business.  You may purchase, redeem or exchange Fund shares either through your financial intermediary or (except for purchases of Class C shares by accounts with no specified financial intermediary) directly from the Fund either by writing to the Fund, P.O. Box 219544, Kansas City, MO 64121-9544, or by calling 1-800-368-2745. The minimum initial purchase or exchange into the Fund is $1,000 for Class A and Class C, $1,000,000 for Class I and $5,000,000 for Class R6 (waived in certain circumstances). There is no minimum for subsequent investments.

Tax Information

If your shares are held in a taxable account, the Fund's distributions will be taxed to you as ordinary income and/or capital gains, unless you are exempt from taxation. If your shares are held in a tax-advantaged account, you will generally be taxed only upon withdrawals from the account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase the Fund's shares through a broker-dealer or other financial intermediary (such as a bank) (collectively, "financial intermediaries"), the Fund, its principal underwriter and its affiliates may pay the financial intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the financial intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary's website for more information.