Putnam
Core Bond Fund

Summary Prospectus

February 28, 2025

Before you invest, you may want to review the fund’s prospectus, which contains more information about the fund and its risks. You can find the fund’s prospectus, statement of additional information, reports to shareholders and other information about the fund online at www.franklintempleton.com/prospectus. You can also get this information at no cost by calling 1-800-225-1581 or by sending an e-mail request to funddocuments@putnam.com.

The fund’s prospectus and statement of additional information, both dated February 28, 2025, as may be supplemented, are all incorporated by reference into this Summary Prospectus.

Goal

The fund seeks high current income consistent with what the Investment Manager (as defined below) believes to be prudent risk.

Fees and expenses

The following tables describe the fees and expenses 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 tables and examples below. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in class A shares of Putnam funds. More information about these and other discounts is available from your financial professional and in How do I buy fund shares? beginning on page 21 of the fund's prospectus, in the Appendix to the fund's prospectus, and in How to buy shares beginning on page 23 of the fund's statement of additional information (“SAI”).

Example

The following hypothetical example is intended to help you compare the cost of investing in the fund with the cost of investing in other funds. It assumes that you invest $10,000 in the fund for the time periods indicated and then, except as indicated, redeem all your shares at the end of those periods. It assumes a 5% return on your investment each year and that the fund’s operating expenses remain the same. Your actual costs may be higher or lower.

Portfolio turnover

The fund pays transaction-related costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or the above example, affect fund performance. The fund’s turnover rate in the most recent fiscal year was 372%.

Investments, risks, and performance

Investments

The fund invests mainly in a diversified portfolio of investment-grade fixed-income securities. The fund invests mainly in bonds of governments and private companies that are investment-grade in quality with intermediate- to long-term maturities (three years or longer). Investment-grade securities are rated at least BBB or its equivalent at the time of purchase by a nationally recognized securities rating organization, or are unrated investments that the Investment Manager believes are of comparable quality.

The fund may invest up to 5% of its total assets in debt investments rated below BBB or its equivalent (also known as below-investment-grade securities) at the time of purchase by each rating agency rating such investments, or in unrated investments that the Investment Manager believes are of comparable quality. However, the fund will not invest in securities that are rated lower than B or its equivalent by each rating agency rating the investment or are unrated securities that we believe are of comparable quality. The fund will not necessarily sell an investment if its rating is reduced (or increased) after purchase.

The fund may consider, among other factors, a company’s or issuer’s credit, interest rate, liquidity and prepayment risks, as well as general market conditions, when deciding whether to buy or sell investments.

Under normal circumstances, the fund will invest at least 80% of its net assets in bonds (bonds include any debt instrument, and may be represented by other investment instruments, including derivatives). This policy may be changed only after 60 days’ notice to shareholders. In addition to bonds, the fund may also invest in other fixed-income instruments. The fund may also use derivatives, such as futures, options, certain foreign currency transactions and swap contracts, for both hedging and non-hedging purposes.

Risks

It is important to understand that you can lose money by investing in the fund.

The value of investments in the fund's portfolio may fall or fail to rise over extended periods of time (including periods of one year or more) for a variety of reasons, including general economic, political or financial market conditions, investor sentiment and market perceptions, government actions, geopolitical events or changes, outbreaks of infectious illnesses or other widespread public health issues, and factors related to a specific issuer, asset class, geography, industry or sector. These and other factors may lead to increased volatility and reduced liquidity in the fund’s portfolio holdings, may negatively impact the fund’s performance, and may exacerbate other risks to which the fund is subject.

The risks associated with bond investments include interest rate risk, which is the risk that the value of the fund’s investments is likely to fall if interest rates rise. Bond investments are also subject to credit risk, which is the risk that issuers of the fund’s investments may default on payment of interest or principal. Bond investments may be more susceptible to downgrades or defaults during economic downturns or other periods of economic stress. Interest rate risk is generally greater for longer-term bonds, and credit risk is generally greater for below-investment-grade bonds (sometimes referred to as "junk bonds"), which can be more sensitive to changes in markets, credit conditions, and interest rates, and may be considered speculative. Mortgage-backed investments, unlike traditional debt investments, are also subject to prepayment risk, which means that they may increase in value less than other bonds when interest rates decline and decline in value more than other bonds when interest rates rise. We may have to invest the proceeds from prepaid investments, including mortgage-backed investments, in other investments with less attractive terms and yields. The fund’s investments in mortgage-backed securities, and in certain other securities and derivatives, may be or become illiquid.

The fund’s investment in mortgage-backed securities may make the fund’s net asset value more susceptible to economic, market, political and other developments affecting the residential and commercial real estate markets and the servicing of mortgage loans secured by real estate properties. During periods of difficult economic conditions, delinquencies and losses on commercial mortgage-backed investments in particular generally increase, including as a result of the effects of those conditions on commercial real estate markets, the ability of commercial tenants to make loan payments, and the ability of a property to attract and retain commercial tenants.

Our use of derivatives may increase the risks of investing in the fund by increasing investment exposure (which may be considered leverage and magnify or otherwise increase investment losses to the fund) or, in the case of many over-the-counter instruments, because of the potential inability to terminate or sell derivative positions and the potential failure of the other party to the instrument to meet its obligations. The risk of a party failing to meet its obligations may increase if the fund has significant exposure to that counterparty. The value of derivatives may move in unexpected ways due to unanticipated market movements, the use of leverage, imperfect correlation between the derivative instrument and the reference asset, or other factors, especially in unusual market conditions, and volatility in the value of derivatives could adversely impact the fund’s returns, obligations and exposures. Derivatives are also subject to other risks, including liquidity risk (e.g., liquidity demands arising from the requirement to make payments to a derivative counterparty), operational risk (e.g., settlement issues or system failures) and legal risk (e.g., insufficient legal documentation or contract enforceability issues).

The fund may be an investment option for mutual funds that are managed by the Investment Manager and its affiliates as “funds of funds.” Additionally, other investors from time to time may make substantial investments in the fund. Such shareholders may at times be considered to control the fund. Dispositions of a large number of shares by these shareholders may adversely affect the fund’s liquidity and net assets. These redemptions may also force the fund to sell securities, which may increase the fund’s brokerage costs.

There is no guarantee that the investment techniques, analyses, or judgments that we apply in making investment decisions for the fund will produce the intended outcome or that the investments we select for the fund will perform as well as other securities that were not selected for the fund. If the quantitative models or data that are used in managing the fund prove to be incorrect or incomplete, investment decisions made in reliance on the models or data may not produce the desired results and the fund may realize losses. We, or the fund's other service providers, may experience disruptions or operating errors that could negatively impact the fund.

The fund may not achieve its goal, and it is not intended to be a complete investment program. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Performance

The accompanying bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year for Class A shares. The table shows the average annual total returns of each class of the fund that has been in operation for at least one full calendar year and also compares the fund’s performance with the average annual total returns of a broad measure of market performance and the Putnam Core Bond Linked Benchmark, which represents the performance of the ICE BofA U.S. Treasury Bill Index through February 27, 2023, and the performance of the Bloomberg U.S. Aggregate Index thereafter. Before February 28, 2023, the fund was managed with a materially different investment strategy and may have achieved materially different performance results under its current investment strategy from that shown for periods before this date. Performance for classes other than those shown may vary from the performance shown to the extent the expenses for those classes differ. The fund makes updated performance information, including its current net asset value per share, available at www.franklintempleton.com.

The fund’s past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future.

Sales charges are not reflected in the accompanying bar chart, and if those charges were included, returns would be less than those shown.

Annual total returns for class A shares before sales charges

Average annual total returns after sales charges

For periods ended 12/31/24

After-tax returns reflect the historical highest individual federal marginal income tax rates and do not reflect state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are shown for class A shares only and will vary for other classes. These after-tax returns do not apply if you hold your fund shares through a 401(k) plan, an IRA, or another tax-advantaged arrangement.

Class C share performance reflects conversion to class A shares after eight years.

Important data provider notices and terms are available at www.franklintempletondatasources.com. All data is subject to change.

Your fund's management

Investment Manager

Franklin Advisers, Inc. (“Franklin Advisers” or the "Investment Manager")

Sub-advisors

Putnam Investment Management, LLC (“Putnam Management”)

Franklin Templeton Investment Management Limited (“FTIML”)

Portfolio managers

Andrew C. Benson
Portfolio Manager of Franklin Advisers and portfolio manager of the fund since 2023.

Albert W. Chan, CFA
Portfolio Manager of Franklin Advisers and portfolio manager of the fund since 2017.

Tina Chou
Portfolio Manager of Franklin Advisers and portfolio manager of the fund since September 2024.

Patrick A. Klein, Ph.D.
Portfolio Manager of Franklin Advisers and portfolio manager of the fund since September 2024.

Michael V. Salm
Portfolio Manager of Franklin Advisers and portfolio manager of the fund since 2008.

Purchase and sale of fund shares

You can open an account, purchase and/or sell fund shares, or exchange them for shares of another Putnam fund by contacting your financial professional or by calling Putnam Investor Services at 1-800-225-1581.

When opening an account, you must complete and mail a Putnam account application, along with a check made payable to the fund, to: Putnam Investor Services, P.O. Box 219697, Kansas City, MO 64121-9697. The minimum initial investment of $500 is currently waived, although the fund reserves the right to reject initial investments under $500 at its discretion. There is no minimum for subsequent investments.

You can sell your shares back to the fund or exchange them for shares of another Putnam fund any day the New York Stock Exchange (“NYSE”) is open. Shares may be sold or exchanged by mail, by phone, or, for exchanges only, online at www.franklintempleton.com. Some restrictions may apply.

Tax information

The fund’s distributions will be taxed as ordinary income or capital gains unless you hold the shares through a tax-advantaged arrangement, in which case you will generally be taxed only upon withdrawal of monies from the arrangement.

Financial intermediary compensation

If you purchase the fund through a broker/dealer or other financial intermediary (such as a bank or financial professional), the fund and its related companies may pay that intermediary for the sale of fund shares and related services. Please bear in mind that these payments may create a conflict of interest by influencing the broker/dealer or other intermediary to recommend the fund over another investment. Ask your advisor or visit your advisor’s website for more information.

Information about the Summary Prospectus, Prospectus, and SAI

The summary prospectus, prospectus, and SAI for a fund provide information concerning the fund. The summary prospectus, prospectus, and SAI are updated at least annually and any information provided in a summary prospectus, prospectus, or SAI can be changed without a shareholder vote unless specifically stated otherwise. The summary prospectus, prospectus, and the SAI are not contracts between the fund and its shareholders and do not give rise to any contractual rights or obligations or any shareholder rights other than any rights conferred explicitly by federal or state securities laws that may not be waived.

Additional information, including current performance, is available at www.franklintempleton.com, by calling 1-800-225-1581, or by e-mailing Putnam at funddocuments@putnam.com.

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