# EDGAR Filing Document

**Accession Number:** 0000732337
**File Stem:** 0000928816-23-000102
**Filing Date:** 2023-1
**Character Count:** 20891
**Document Hash:** 14d78f545ec0e155070fd522d41ff2a6
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000928816-23-000102.hdr.sgml**: 20230126

**ACCESSION NUMBER**: 0000928816-23-000102

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 5

**FILED AS OF DATE**: 20230126

**DATE AS OF CHANGE**: 20230126

**EFFECTIVENESS DATE**: 20230126

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** PUTNAM MORTGAGE SECURITIES FUND
- **CENTRAL INDEX KEY:** 0000732337
- **IRS NUMBER:** 042811119
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 0930

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 002-87634
- **FILM NUMBER:** 23555342

**BUSINESS ADDRESS:**
- **STREET 1:** 100 FEDERAL STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02110
- **BUSINESS PHONE:** 6172921000

**MAIL ADDRESS:**
- **STREET 1:** 100 FEDERAL STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02110

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** PUTNAM U S GOVERNMENT INCOME TRUST
- **DATE OF NAME CHANGE:** 19920703

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** PUTNAM U S GOVERNMENT GUARANTEED SECURITIES INCOME TRUST
- **DATE OF NAME CHANGE:** 19910102

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** PUTNAM UNITED STATES GOVERNMENT SECURITIES INCOME FUND
- **DATE OF NAME CHANGE:** 19840806

## Series and Classes Contracts Data

### PUTNAM MORTGAGE SECURITIES FUND (Series ID: S000006570)

| Class ID   | Class Name      | Ticker Symbol   |
|:---|:---|:---|
| C000017922 | Class A Shares  | PGSIX           |
| C000017923 | Class B Shares  | PGSBX           |
| C000017924 | Class C Shares  | PGVCX           |
| C000017926 | Class R Shares  | PGVRX           |
| C000017927 | Class Y Shares  | PUSYX           |
| C000200295 | Class R6 Shares |  |

![coverlogo.jpg](coverlogo.jpg)

![worldofinvesting.jpg](worldofinvesting.jpg)

<br>Putnam <br> Mortgage Securities <br> Fund <br>

Summary prospectus

1 \| 30 \| 23 <br>

 **Before you invest, you may wish to review the fund's prospectus, which contains more information about the fund and its risks. You may obtain the prospectus and other information about the fund, including the statement of additional information (SAI) and most recent reports to shareholders, at no cost by visiting putnam.com/funddocuments, calling 1-800-225-1581, or e-mailing Putnam at funddocuments@putnam.com.** <br>

 **The fund's prospectus and SAI, both dated 1/30/23, are incorporated by reference into this summary prospectus.**<br>

<u>FUND SYMBOLS </u> <u>CLASS A </u> <u>CLASS B </u> <u>CLASS C </u> <u>CLASS R </u> <u>CLASS R6 </u> <u>CLASS Y </u> <br> PGSIX PGSBX PGVCX PGVRX POLYX PUSYX

<br>Putnam Mortgage Securities Fund

 **Goal**

Putnam Mortgage Securities Fund seeks as high a level of current income as Putnam Investment Management, LLC believes is consistent with preservation of capital.

 **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 18 of the fund's prospectus, in the Appendix to the fund's prospectus, and in *How to buy shares* beginning on page II-1 of the fund's statement of additional information (SAI).

 **Shareholder fees** *(fees paid directly from your investment)*

---

| | | |
|:---|:---|:---|
| **Share class** | **Maximum sales charge (load) imposed on purchases (as a percentage of offering price)** | **Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)** |
| Class A | 4.00% | 1.00%\* |
| Class B |  | 5.00%\*\* |
| Class C |  | 1.00%\*\*\* |
| Class R |  |  |
| Class R6 |  |  |
| Class Y |  |  |

---

 **Annual fund operating expenses** <br> *(expenses you pay each year as a percentage of the value of your investment)*

---

| | | | | |
|:---|:---|:---|:---|:---|
| **Share class** | **Management fees** | **Distribution and service (12b-1) fees** | **Other <br> expenses** | **Total annual fund operating <br> expenses** |
| Class A | 0.39% | 0.25% | 0.28% | 0.92% |
| Class B | 0.39% | 1.00% | 0.28% | 1.67% |
| Class C | 0.39% | 1.00% | 0.28% | 1.67% |
| Class R | 0.39% | 0.50% | 0.28% | 1.17% |
| Class R6 | 0.39% | N/A | 0.14% | 0.53% |
| Class Y | 0.39% | N/A | 0.28% | 0.67% |

---

\* Applies only to certain redemptions of shares bought with no initial sales charge.

\*\* This charge is phased out over six years.

\*\*\* This charge is eliminated after one year.

 **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.

---

| | | | | |
|:---|:---|:---|:---|:---|
| **Share class** | **1 year** | **3 years** | **5 years** | **10 years** |
| Class A | $490 | $682 | $889 | $1486 |
| Class B | $670 | $826 | $1107 | $1777 |
| Class B (no redemption) | $170 | $526 | $907 | $1777 |
| Class C | $270 | $526 | $907 | $1777 |
| Class C (no redemption) | $170 | $526 | $907 | $1777 |
| Class R | $119 | $372 | $644 | $1420 |
| Class R6 | $54 | $170 | $296 | $665 |
| Class Y | $68 | $214 | $373 | $835 |

---

 **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 863%.

 **Investments, risks, and performance**

 **Investments**

We invest mainly in mortgages, mortgage-related fixed income securities and related derivatives that are either investment-grade or below-investment-grade in quality (sometimes referred to as "junk bonds"). Under normal circumstances, we invest at least 80% of the fund's net assets (plus any borrowings for investment purposes) in mortgages, mortgage-related fixed income securities and related derivatives (i.e., derivatives used to acquire exposure to, or whose underlying securities are, mortgages or mortgage-related securities). The fund generally uses the net unrealized gain or loss, or market value, of mortgage-related derivatives for purposes of this policy, but may use the notional value of a derivative if that is determined to be a more appropriate measure of the fund's investment exposure. This policy may be changed only after 60 days' notice to shareholders.

We expect to invest in mortgage-backed investments that are obligations of U.S. government agencies and instrumentalities and accordingly are backed by the full faith and credit of the United States (e.g., Ginnie Mae mortgage-backed bonds) as well as in mortgage-backed investments that are backed by only the credit of a federal agency or government-sponsored entity (e.g., Fannie Mae and Freddie Mac mortgage-backed bonds), and that have short- to long-term maturities.

We also expect to invest in lower-rated, higher-yielding mortgage-backed securities, including non-agency residential mortgage-backed securities (which may be backed by non-qualified or "sub-prime" mortgages), commercial mortgage-backed securities, and collateralized mortgage obligations (including interest only, principal

only, and other prepayment derivatives). Non-agency (i.e., privately issued) securities typically are lower-rated and higher yielding than securities issued or backed by agencies such as Ginnie Mae, Fannie Mae or Freddie Mac. The fund currently has significant investment exposure to commercial mortgage-backed securities. While our emphasis will be on mortgage-backed securities, we may also invest to a lesser extent in other types of asset-backed securities.

We may consider, among other factors, credit, interest rate, prepayment and liquidity risks, as well as general market conditions, when deciding whether to buy or sell investments. We typically use to a significant extent derivatives, including credit default swaps, interest rate swaps, total return swaps, to-be-announced (TBA) commitments, futures, options and swaptions, including on mortgage-backed securities and indices, for both hedging and non-hedging purposes, including to obtain or adjust exposure to mortgage-backed investments.

 **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 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, geography, industry or sector, such as the housing or real estate markets. 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. Default risk is generally higher for non-qualified mortgages. Interest rate risk is generally greater for longer-term bonds, and credit risk is generally greater for below-investment grade bonds, which can be more sensitive to changes in markets, credit conditions, and interest rates, and may be considered speculative.

Mortgage- and asset-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- and asset-backed investments, in other investments with less attractive terms and yields. The fund's investments in mortgage-backed securities and asset-backed securities, and in certain other securities and derivatives, may be or become illiquid.

The fund's concentration in an industry group composed of privately issued residential and commercial mortgage-backed securities and mortgage-backed securities issued or guaranteed by the U.S. government or its agencies or instrumentalities 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) or, in the case of many over-the-counter instruments, because of the potential inability to terminate or sell derivatives 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).

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. 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 performance information below gives some indication of the risks associated with an investment in the fund by showing the fund's performance year to year and over time. Before April 19, 2018, 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. The bar chart does not reflect the impact of sales charges. If it did, performance would be lower. Please remember that past performance is not necessarily an indication of future results. Monthly performance figures for the fund are available at putnam.com.

 **Annual total returns for class A shares before sales charges**

![p5032sumreturnschart.jpg](p5032sumreturnschart.jpg)

---

| | |
|:---|:---|
| Best calendar quarter <br> **Q4 2020** | 4.54% |
| Worst calendar quarter <br> **Q1 2020** | –8.89% |

---

 **Average annual total returns after sales charges** *(for periods ended 12/31/22)*

---

| | | | |
|:---|:---|:---|:---|
| **Share class** | **1 year** | **5 years** | **10 years** |
| Class A before taxes | –14.39% | –1.92% | –0.36% |
| Class A after taxes on distributions | –18.35% | –3.94% | –1.90% |
| Class A after taxes on distributions and sale of fund shares | –8.45% | –2.19% | –0.87% |
| Class B before taxes | –15.45% | –2.16% | –0.54% |
| Class C before taxes | –12.22% | –1.85% | –0.55% |
| Class R before taxes | –11.08% | –1.37% | –0.21% |
| Class R6 before taxes\* | –10.45% | –0.75% | 0.36% |
| Class Y before taxes | –10.58% | –0.87% | 0.29% |
| Bloomberg U.S. MBS Index (no deduction for fees, expenses or taxes) | –11.81% | –0.53% | 0.74% |
| Putnam Mortgage Securities Linked Benchmark (no deduction for fees, expenses or taxes) | –11.81% | –0.52% | 0.58% |

---

\* Performance for class R6 shares prior to their inception (4/20/18) is derived from the historical performance of class Y shares and has not been adjusted for the lower investor servicing fees applicable to class R6 shares; had it, returns would have been higher.

The Putnam Mortgage Securities Linked Benchmark represents the performance of the Bloomberg GNMA Index through April 18, 2018, and the performance of the Bloomberg U.S. MBS Index thereafter.

All Bloomberg indices provided by Bloomberg Index Services Limited.

BLOOMBERG® is a trademark and service mark of Bloomberg Finance L.P. and its affiliates (collectively "Bloomberg"). Bloomberg, or Bloomberg's licensors, own all proprietary rights in the Bloomberg Indices. Neither Bloomberg nor Bloomberg's licensors approve or endorse this material or guarantee the accuracy or completeness of any information herein, or make any warranty, express or implied, as to the results to be obtained therefrom, and to the maximum extent allowed by law, neither shall have any liability or responsibility for injury or damages arising in connection therewith.

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

 **Your fund's management**

 **Investment advisor**

Putnam Investment Management, LLC

 **Portfolio managers**

 **Michael Salm** <br> Chief Investment Officer, Fixed<br> Income, portfolio manager of the fund<br> since 2007

 **Brett Kozlowski** <br> Co-Head of Structured Credit, portfolio <br> manager of the fund since 2018

 **Jatin Misra** <br> Co-Head of Structured Credit, portfolio <br> manager of the fund since 2017

 **Sub-advisor**

Putnam Investments Limited\*

\* Though the investment advisor has retained the services of Putnam Investments Limited (PIL), PIL does not currently manage any assets of the fund.

 **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. Purchases of class B shares are closed to new and existing investors except by exchange from class B shares of another Putnam fund or through dividend and/or capital gains reinvestment.

When opening an account, you must complete and mail a Putnam account application, along with a check made payable to the fund, to: Putnam Investments, P.O. Box 219697, Kansas City, MO 64121-9697. The minimum initial investment of $500 is currently waived, although Putnam 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 putnam.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 putnam.com/funddocuments, by calling 1-800-225-1581, or by e-mailing Putnam at funddocuments@putnam.com.**

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