PIMCO GNMA and Government Securities Fund

SUMMARY PROSPECTUS

July 31, 2020


Share Class:	Inst	I-2	I-3	A	C
Ticker:	PDMIX	PPGNX	PANNX	PAGNX	PCGNX

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of the Fund’s annual and semi-annual shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from the Fund or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on the Fund’s website, pimco.com/literature, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive shareholder reports and other communications from the Fund electronically by visiting pimco.com/edelivery or by contacting your financial intermediary, such as a broker-dealer or bank.

You may elect to receive all future reports in paper free of charge. If you own these shares through a financial intermediary, such as a broker-dealer or bank, you may contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. If you invest directly with the Fund, you can inform the Fund that you wish to continue receiving paper copies of your shareholder reports by calling 888.87.PIMCO (888.877.4626). Your election to receive reports in paper will apply to all funds held with the fund complex if you invest directly with the Fund or to all funds held in your account if you invest through a financial intermediary, such as a broker-dealer or bank.

Before you invest, you may want to review the Fund’s prospectus, which, as supplemented, contains more information about the Fund and its risks. You can find the Fund’s prospectus, reports to shareholders (once available) and other information about the Fund online at http://investments.pimco.com/prospectuses . You can also get this information at no cost by calling 888.87.PIMCO or by sending an email request to piprocess@dstsystems.com. The Fund’s prospectus and Statement of Additional Information, dated July 31, 2020, respectively, as supplemented, are incorporated by reference into this Summary Prospectus.

Investment Objective

The Fund seeks maximum total return, consistent with preservation of capital and prudent investment management.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. In addition to the fees and expenses described below, you may also be required to pay brokerage commissions on purchases and sales of Institutional Class, I-2 or I-3 shares of the Fund. 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 eligible funds offered by PIMCO Equity Series and PIMCO Funds. More information about these and other discounts is available in the “Classes of Shares” section on page 77 of the Fund’s prospectus, Appendix B to the Fund’s prospectus (Financial Firm-Specific Sales Charge Waivers and Discounts) or from your financial professional.

Shareholder Fees (fees paid directly from your investment):


	Inst Class	I-2	I-3	Class A	Class C
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	None	None	None	3.75%	None
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of the original purchase price or redemption price)	None	None	None	1.00%	1.00%

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


	Inst Class	I-2	I-3	Class A	Class C
Management Fees	0.50%	0.60%	0.70%	0.65%	0.65%
Distribution and/or Service (12b-1) Fees	N/A	N/A	N/A	0.25%	1.00%
Other Expenses⁽¹⁾	0.33%	0.33%	0.33%	0.33%	0.33%
Total Annual Fund Operating Expenses	0.83%	0.93%	1.03%	1.23%	1.98%
Fee Waiver and/or Expense Reimbursement⁽²⁾	N/A	N/A	(0.05%)	N/A	N/A
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	0.83%	0.93%	0.98%	1.23%	1.98%

“Other Expenses” include interest expense of 0.33%. Interest expense is borne by the Fund separately from the management fees paid to Pacific Investment Management Company LLC (“PIMCO”). Excluding interest expense, Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement are 0.50%, 0.60%, 0.65%, 0.90% and 1.65% for Institutional Class, I-2, I-3, Class A and Class C shares, respectively.

PIMCO has contractually agreed, through July 31, 2021, to reduce its supervisory and administrative fee for the Fund’s I-3 shares by 0.05% of the average daily net assets attributable to I-3 shares of the Fund. This Fee Waiver Agreement renews annually unless terminated by PIMCO upon at least 30 days’ prior notice to the end of the contract term.

Example. The Example is intended to help you compare the cost of investing in Institutional Class, I-2, I-3, Class A or Class C shares of the Fund with the costs of investing in other mutual funds. The Example assumes that you invest $10,000 in the noted class of shares for the time periods indicated, and then redeem all your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Investors may pay brokerage commissions on their purchases and sales of Institutional Class, I-2 or I-3 shares of the Fund, which are not reflected in the Example. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

If you redeem your shares at the end of each period:


	1 Year	3 Years	5 Years	10 Years
Institutional Class	$85	$265	$460	$1,025
I-2	$95	$296	$515	$1,143
I-3	$100	$323	$564	$1,255
Class A	$496	$751	$1,025	$1,808
Class C	$301	$621	$1,068	$2,306

If you do not redeem your shares:


	1 Year	3 Years	5 Years	10 Years
Class A	$496	$751	$1,025	$1,808
Class C	$201	$621	$1,068	$2,306

Portfolio Turnover

The Fund pays transaction costs when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual

PIMCO FUNDS | SUMMARY PROSPECTUS

PIMCO GNMA and Government Securities Fund

Fund Operating Expenses or in the Example tables, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 903% of the average value of its portfolio.

Principal Investment Strategies

The Fund seeks to achieve its investment objective by investing under normal circumstances at least 80% of its assets in a diversified portfolio of securities of varying maturities issued by the Government National Mortgage Association (“GNMA”) and of securities issued or guaranteed by the U.S. Government, its agencies or government-sponsored enterprises, which may be represented by forwards or derivatives such as options, futures contracts or swap agreements. The Fund is neither sponsored by nor affiliated with GNMA. The average portfolio duration of this Fund normally varies from one to seven years based on PIMCO’s market forecasts. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates. The Fund may invest without limit in securities issued or guaranteed by the U.S. Government, its agencies or government-sponsored enterprises. In addition, the Fund may invest up to 10% of its total assets in investment grade securities rated below Aaa by Moody’s Investors Service, Inc. (“Moody’s”), or equivalently rated by Standard & Poor’s Ratings Services (“S&P”) or Fitch, Inc. (“Fitch”), subject to a minimum rating of Baa by Moody’s, or equivalently rated by S&P or Fitch, or, if unrated, determined by PIMCO to be of comparable quality. In the event that ratings services assign different ratings to the same security, PIMCO will use the highest rating as the credit rating for that security. The Fund may not invest in securities denominated in foreign currencies, but may invest without limit in U.S. dollar-denominated securities of foreign issuers. The Fund may invest up to 10% of its total assets in U.S. dollar-denominated securities and instruments that are economically tied to emerging market countries.

The Fund may invest, without limitation, in derivative instruments, such as options, futures contracts or swap agreements, or in mortgage- or asset-backed securities, subject to applicable law and any other restrictions described in the Fund’s prospectus or Statement of Additional Information. The Fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis and may engage in short sales. The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls). The “total return” sought by the Fund consists of income earned on the Fund’s investments, plus capital appreciation, if any, which generally arises from decreases in interest rates or improving credit fundamentals for a particular sector or security.

GNMA, a wholly-owned U.S. Government corporation, is authorized to guarantee, with the full faith and credit of the U.S. Government, the timely payment of principal and interest on securities issued by institutions approved by GNMA and backed by pools of mortgages insured by the Federal Housing Administration, or guaranteed by the Department of Veterans Affairs. The Fund may also invest up to 10% of its total assets in preferred securities.

Principal Risks

It is possible to lose money on an investment in the Fund. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return are listed below.

Interest Rate Risk: the risk that fixed income securities will decline in value because of an increase in interest rates; a fund with a longer average portfolio duration will be more sensitive to changes in interest rates than a fund with a shorter average portfolio duration

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

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

Market Risk: the risk that the value of securities owned by the Fund may go up or down, sometimes rapidly or unpredictably, due to factors affecting securities markets generally or particular industries

Issuer Risk: the risk that the value of a security may decline for a reason directly related to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods or services

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

Derivatives Risk: the risk of investing in derivative instruments (such as futures, swaps and structured securities), including leverage, liquidity, interest rate, market, credit and management risks, and valuation complexity. Changes in the value of a derivative may not correlate perfectly with, and may be more sensitive to market events than, the underlying asset, rate or index, and the Fund could lose more than the initial amount invested. The Fund’s use of derivatives may result in losses to the Fund, a reduction in the Fund’s returns and/or increased volatility. Over-the-counter (“OTC”) derivatives are also subject to the risk that a counterparty to the transaction will not fulfill its contractual obligations to the other party, as many of the protections afforded to centrally-cleared derivative transactions might not be available for OTC derivatives. The primary credit risk on derivatives that are exchange-traded or traded through a central clearing counterparty resides with the Fund’s clearing broker, or the clearinghouse. Changes in regulation relating to a mutual fund’s use of derivatives and

2SUMMARY PROSPECTUS | PIMCO FUNDS

Summary Prospectus

related instruments could potentially limit or impact the Fund’s ability to invest in derivatives, limit the Fund’s ability to employ certain strategies that use derivatives and/or adversely affect the value of derivatives and the Fund’s performance

Equity Risk: the risk that the value of equity securities, such as common stocks and preferred securities, may decline due to general market conditions which are not specifically related to a particular company or to factors affecting a particular industry or industries. Equity securities generally have greater price volatility than fixed income securities

Mortgage-Related and Other Asset-Backed Securities Risk: the risks of investing in mortgage-related and other asset-backed securities, including interest rate risk, extension risk, prepayment risk and credit risk

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

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

Leveraging Risk: the risk that certain transactions of the Fund, such as reverse repurchase agreements, loans of portfolio securities, and the use of when-issued, delayed delivery or forward commitment transactions, or derivative instruments, may give rise to leverage, magnifying gains and losses and causing the Fund to be more volatile than if it had not been leveraged. This means that leverage entails a heightened risk of loss

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

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

LIBOR Transition Risk: the risk related to the anticipated discontinuation of the London Interbank Offered Rate (“LIBOR”) by the end of 2021. Certain instruments held by the Fund rely in some fashion upon LIBOR. Although the transition process away from LIBOR has become increasingly well-defined in advance of the anticipated discontinuation date, there remains uncertainty regarding the nature of any replacement rate, and any potential effects of the transition away from LIBOR on the Fund or on certain instruments in which the Fund invests can be difficult to ascertain. The transition process may involve, among other things, increased volatility

or illiquidity in markets for instruments that currently rely on LIBOR and may result in a reduction in value of certain instruments held by the Fund

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

Performance Information

The performance information shows summary performance information for the Fund in a bar chart and an Average Annual Total Returns table. The information provides some indication of the risks of investing in the Fund by showing changes in its performance from year to year and by showing how the Fund’s average annual returns compare with the returns of a broad-based securities market index and an index of similar funds. Absent any applicable fee waivers and/or expense limitations, performance would have been lower. The bar chart shows performance of the Fund’s Institutional Class shares. Performance for Class A and Class C shares in the Average Annual Total Returns table reflects the impact of sales charges. The Fund’s past performance, before and after taxes, is not necessarily an indication of how the Fund will perform in the future.

The Bloomberg Barclays GNMA Index is an unmanaged index covering mortgage-backed pass-through securities of the GNMA. The Lipper GNMA Funds Average is a total return performance average of funds tracked by Lipper, Inc. that invest at least 65% of their assets in mortgages/securities issued or guaranteed as to principal and interest by the U.S. government and certain federal agencies.

Performance for the Fund is updated daily and quarterly and may be obtained as follows: daily and quarterly updates on the net asset value and performance page at https://www.pimco.com/en-us/product-finder.

Calendar Year Total Returns — Institutional Class*

*The year-to-date return as of June 30, 2020 is 4.35%. For the periods shown in the bar chart, the highest quarterly return was 3.78% in the Q2 2010, and the lowest quarterly return was -2.70% in the Q2 2013.

Average Annual Total Returns (for periods ended 12/31/19)


	1 Year	5 Years	10 Years
Institutional Class Return Before Taxes	6.55%	2.50%	3.50%
Institutional Class Return After Taxes on Distributions⁽¹⁾	5.08%	1.25%	2.03%

July 31, 2020 | SUMMARY PROSPECTUS3

PIMCO GNMA and Government Securities Fund


	1 Year	5 Years	10 Years
Institutional Class Return After Taxes on Distributions and Sales of Fund Shares⁽¹⁾	3.86%	1.35%	2.09%
I-2 Return Before Taxes	6.44%	2.40%	3.40%
I-3 Return Before Taxes	6.39%	2.34%	3.35%
Class A Return Before Taxes	2.15%	1.31%	2.70%
Class C Return Before Taxes	4.34%	1.33%	2.32%
Bloomberg Barclays GNMA Index (reflects no deductions for fees, expenses or taxes)	5.85%	2.32%	3.21%
Lipper GNMA Funds Average (reflects no deductions for taxes)	5.55%	1.76%	2.70%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. In some cases the return after taxes may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of Fund shares at the end of the measurement period. After-tax returns are for Institutional Class shares only. After-tax returns for other classes will vary.

Investment Adviser/Portfolio Managers

. .

PIMCO serves as the investment adviser for the Fund. The Fund’s portfolio is jointly and primarily managed by Mike Cudzil and Daniel Hyman. Messrs. Cudzil and Hyman are Managing Directors of PIMCO. Mr. Cudzil has managed the Fund since January 2013, and Mr. Hyman has managed the Fund since July 2012.

Purchase and Sale of Fund Shares

Fund shares may be purchased or sold (redeemed) on any business day (normally any day when the New York Stock Exchange (“NYSE”) is open). Generally, purchase and redemption orders for Fund shares are processed at the net asset value next calculated after an order is received by the Fund.

Institutional Class, I-2 and I-3

The minimum initial investment for Institutional Class, I-2 and I-3 shares of the Fund is $1 million, except that the minimum initial investment may be modified for certain financial firms that submit orders on behalf of their customers.

You may sell (redeem) all or part of your Institutional Class, I-2 and I-3 shares of the Fund on any business day. If you are the registered owner of the shares on the books of the Fund, depending on the elections made on the Account Application, you may sell by:

■	Sending a written request by regular mail to: PIMCO Funds P.O. Box 219024, Kansas City, MO 64121-9024 or by overnight mail to: PIMCO Funds c/o DST Asset Manager Solutions, Inc. 430 W. 7th Street, STE 219024, Kansas City, MO 64105-1407

■	Calling us at 888.87.PIMCO and a Shareholder Services associate will assist you

■	Sending a fax to our Shareholder Services department at 816.421.2861

■	Sending an e-mail to piprocess@dstsystems.com

Class A and Class C

The minimum initial investment for Class A and Class C shares of the Fund is $1,000. The minimum subsequent investment for Class A and Class C shares is $50. The minimum initial investment may be modified for certain financial firms that submit orders on behalf of their customers. You may purchase or sell (redeem) all or part of your Class A and Class C shares through a broker-dealer, or other financial firm, or, if you are the registered owner of the shares on the books of the Fund, by regular mail to PIMCO Funds, P.O. Box 219294, Kansas City, MO 64121-9294 or overnight mail to PIMCO Funds, c/o DST Asset Manager Solutions, Inc., 430 W. 7th Street, STE 219294, Kansas City, MO 64105-1407. The Fund reserves the right to require payment by wire or U.S. Bank check in connection with accounts opened directly with the Fund by Account Application.

Tax Information

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

Payments to Broker-Dealers and Other Financial Firms

If you purchase shares of the Fund through a broker-dealer or other financial firm (such as a bank), the Fund and/or its related companies (including PIMCO) may pay the financial firm for the sale of those shares of the Fund and/or related services. These payments may create a conflict of interest by influencing the broker-dealer or other financial firm and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial firm’s Web site for more information.

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