PIMCO RAE US Small Fund

Summary Prospectus

October 31, 2025 (as supplemented August 18, 2026)

Share Class:	Inst	I-2	A
Ticker:	PMJIX	PMJPX	PMJAX

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 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@sscinc.com. The Fund’s prospectus and Statement of Additional Information, both dated October 31, 2025, as supplemented, are incorporated by reference into this Summary Prospectus.

Investment Objective

The Fund seeks long-term capital appreciation.

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. 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 $50,000 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 50 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	Class A
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	None	None	3.75%
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of the original purchase price or redemption price)	None	None	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	Class A
Management Fees	0.50%	0.60%	0.65%
Distribution and/or Service (12b-1) Fees	N/A	N/A	0.25%
Total Annual Fund Operating Expenses	0.50%	0.60%	0.90%

Example. The Example is intended to help you compare the cost of investing in Institutional Class, I-2 or Class A 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 hold or 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 shares or I-2 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	$51	$160	$280	$628
I-2	$61	$192	$335	$750
Class A	$463	$651	$855	$1,441

If you do not redeem your shares:

	1 Year	3 Years	5 Years	10 Years
Class A	$463	$651	$855	$1,441

Portfolio Turnover

The Fund 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 and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual 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 59% 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 securities of small companies economically tied to the United States (for purposes of this section only, “U.S. companies”). Specifically, under normal circumstances, the Fund will obtain exposure to a portfolio of stocks of small U.S. companies (“RAE US Small Portfolio”) through investment in the securities that comprise the RAE US Small Portfolio. The stocks are selected by the Fund’s sub-adviser, Syzygy Asset Management (“Sub-Adviser”), from a broad universe of companies which satisfy certain liquidity and capacity requirements.

The Sub-Adviser uses the RAE™ methodology for portfolio construction. The RAE™ methodology is a rules-based model that selects stocks using quantitative signals that indicate higher expected returns, e.g., value, quality, and momentum. The model then weights selected stocks using their fundamental measures of company size, e.g., sales, cash flow, dividends and book value. The Sub-Adviser applies the RAE™ methodology to small-sized U.S. companies determined by percentage of cumulative fundamental measures of company size. The fundamental weights of U.S. companies are sorted in descending order where the top cumulative 86% weights are eligible as large and mid-sized companies and the remaining companies are eligible as small-sized companies. Actual stock positions in the RAE US Small Portfolio, which drift apart from target weights as market prices change, are rebalanced to target weights periodically. The RAE™ methodology’s systematic portfolio rebalancing reflects a value orientation. Portfolio managers do not have discretion with respect to the allocations determined by the RAE™ methodology. The RAE™ methodology is not updated according to any predetermined schedule.

PIMCO Equity Series | Summary Prospectus

PIMCO RAE US Small Fund

The Sub-Adviser provides investment advisory services in connection with the Fund’s use of the RAE US Small Portfolio by, among other things, providing PIMCO with the constituents and target weights in the RAE US Small Portfolio. The Fund seeks to remain invested in the securities that comprise the RAE US Small Portfolio even when the value of the RAE US Small Portfolio is declining.

The Fund may invest, without limitation, in equity and equity-related securities, including common and preferred securities. Equity-related securities include securities having an equity component (e.g., hybrids, bank capital) and equity derivatives. With respect to investments in equity securities, there is no limitation on the market capitalization range of the issuers in which the Fund may invest. The Fund may also invest in derivative instruments, such as options, forwards, futures contracts, options on futures and swap agreements, consistent with its investment objective. The Fund may also invest in real estate investment trusts (“REITs”). The Fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis. The Fund may also enter into reverse repurchase agreements and lend portfolio 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.

Equity Risk: the risk that the value of equity or equity-related 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 or equity-related securities generally have greater price volatility than fixed income securities. In addition, preferred securities may be subject to greater credit risk or other risks, such as risks related to deferred and omitted distributions, limited voting rights, liquidity, interest rates, regulatory changes and special redemption rights

Value Investing Risk: a value stock may decrease in price or may not increase in price as anticipated by the Sub-Adviser if it continues to be undervalued by the market or the factors that the portfolio manager believes will cause the stock price to increase do not occur

Market Risk: the risk that the value of securities owned by the Fund may fluctuate, sometimes rapidly or unpredictably, due to a variety of factors affecting securities markets generally or particular industries or sectors

Issuer Risk: the risk that the value of a security may decline for reasons related to the issuer, such as management performance, changes in financial condition or credit rating, financial leverage, reputation or reduced demand for the issuer’s goods or services

Credit Risk: the risk that the Fund could experience losses if the counterparty to a derivative contract, or the issuer or guarantor of collateral, 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

Distressed Company Risk: the risk that securities of distressed companies may be subject to greater levels of market, credit, issuer and liquidity risks. Distressed companies may be engaged in restructurings, bankruptcy proceedings, or other financial difficulties which may cause the value of their securities to fluctuate rapidly or unpredictably

Real Estate Risk: the risk that the Fund’s investments in real estate investment trusts (“REITs”) or real estate-linked derivative instruments will subject the Fund to risks similar to those associated with direct ownership of real estate, including risks related to losses from casualty or condemnation, changes in local and general economic conditions, fluctuations in supply and demand, interest rate changes, zoning laws, regulatory limitations on rents, property taxes and operating expenses. The Fund’s investments in REITs or real estate-linked derivative instruments subject it to management and tax risks. In addition, REITs that are privately held or not traded on a national securities exchange may subject the Fund to liquidity and valuation risk

Liquidity Risk: the risk that a particular investment may be difficult to purchase or sell and that the Fund may be unable to sell investments at an advantageous time or price or achieve its desired level of exposure to a certain sector. The liquidity of the Fund’s shares may be constrained by the liquidity of the Fund’s portfolio holdings

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, and 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. The use of leverage may also increase the Fund’s sensitivity to interest rate changes and other market risks

Management Risk: the risk that the investment techniques and risk analyses applied by the Sub-Adviser, including the use of quantitative models or methods, 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 the Sub-Adviser and the individual portfolio managers in connection with managing the Fund and may cause the Sub-Adviser to restrict or prohibit participation in certain investments. There is no guarantee that the investment objective of the Fund will be achieved

Small Company Risk: the risk that the value of equity securities issued by small companies, ranked by fundamental size as determined by the Sub-Adviser, may go up or down, sometimes rapidly and unpredictably, due to narrow markets and limited managerial and financial resources

Derivatives Risk: the risk of investing in derivative instruments (such as forwards, futures, options, swaps and structured securities) and other similar investments, including leverage, liquidity, interest rate, market, counterparty (including credit), operational, legal and management risks, and valuation complexity. Changes in the value of a derivative or other similar investment may not correlate perfectly with, and may be

2 Summary Prospectus | PIMCO Equity Series

Summary Prospectus

more sensitive to market events than, the underlying asset, rate or index, and the Fund could lose more than the initial amount invested. Changes in the value of a derivative or other similar instrument may also create margin delivery or settlement payment obligations for the Fund. The Fund’s use of derivatives or other similar investments may result in losses to the Fund, a reduction in the Fund’s returns and/or increased volatility. Non-centrally-cleared over-the-counter (“OTC”) derivatives or other similar investments 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 non-centrally cleared OTC derivatives or other similar investments. The primary credit risk on derivatives or other similar investments that are exchange-traded or traded through a central clearing counterparty resides with the Fund's clearing broker or the clearinghouse. Changes in regulations relating to a registered fund’s use of derivatives and 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 or other similar investments and/or adversely affect the value of derivatives or other similar investments and the Fund’s performance

Model Risk: the risk that the Fund’s investment models used in making investment allocation decisions may not adequately take into account certain factors, or may contain design flaws or faulty assumptions, and may rely on incomplete or inaccurate data inputs, any of which may result in a decline in the value of an investment in the Fund. The performance of the investment models may be impacted by software or other technology malfunctions, human error, programming inaccuracies, power loss, and other events or circumstances, which may be difficult to detect and may be beyond the control of 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 certain indexes. A privately offered fund managed by the Fund’s Sub-Adviser was reorganized into the Fund as of the date the Fund commenced operations (June 5, 2015). This privately offered fund was organized on August 30, 2005 and commenced operations on September 29, 2005 and had an investment objective and strategies that were, in all material respects, the same as those of the Fund, and was managed by the Fund’s Sub-Adviser in a manner that, in all material respects, complied with the investment guidelines and restrictions of the Fund. However, the privately offered fund was not registered as an investment company under the Investment Company Act of 1940, as amended (the “1940 Act”), and the privately offered

fund was not subject to certain investment limitations, diversification requirements, liquidity requirements, and other restrictions imposed by the 1940 Act and the Internal Revenue Code of 1986 which, if applicable, may have adversely affected its performance.

The Fund’s performance for periods prior to the commencement of operations is that of the privately offered fund (net of actual fees and expenses charged to individual privately offered fund accounts in the aggregate). The performance of the privately offered fund has not been restated to reflect the fees, estimated expenses and fee waivers and/or expense limitations applicable to each class of shares of the Fund. If the performance of the privately offered fund had been restated to reflect the applicable fees and expenses of each class of shares of the Fund, the performance may have been higher or lower than the performance shown in the bar chart and Average Annual Total Returns table below. For periods following the Fund's commencement of operations on June 5, 2015, the performance of each class of shares differs as a result of the different levels of fees and expenses applicable to each class of shares, and performance for Class A shares reflects the impact of sales charges. Absent any applicable fee waivers and/or expense limitations, performance would have been lower. The Fund’s past performance, before and after taxes, is not necessarily an indication of how the Fund will perform in the future.

In addition to the Fund’s performance, the Average Annual Total Returns table includes performance of: (i) a broad-based securities market index (i.e., a regulatory index) and (ii) two supplemental indexes. It is not possible to invest directly in an unmanaged index. The Fund’s regulatory index is the S&P 500 Index. The Fund’s regulatory index is shown in connection with certain regulatory requirements to provide a broad measure of market performance. The S&P 500 Index is an unmanaged market index generally considered representative of the stock market as a whole. The S&P 500 Index is composed of 500 selected common stocks that represent approximately two-thirds of the total market value of all U.S. common stocks. The S&P 500 Index focuses on the large-cap segment of the U.S. equities market. The Russell 2000® Value Index is a supplemental index of the Fund. The Russell 2000® Value Index, a subset of the Russell 2000® Index, measures the performance of the small-capitalization value sector of the U.S. equity market, as defined by FTSE Russell. The Russell 2000® Index is also a supplemental index of the Fund. The Russell 2000® Index is composed of 2,000 of the smallest companies in the Russell 3000® Index and is considered to be representative of the small cap market in general.

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.

October 31, 2025 (as supplemented August 18, 2026) | SUMMARY PROSPECTUS 3

PIMCO RAE US Small Fund

Calendar Year Total Returns — Institutional Class

Best Quarter	December 31, 2020	32.93%
Worst Quarter	March 31, 2020	-37.33%
Year-to-Date	September 30, 2025	2.54%

Average Annual Total Returns (for periods ended 12/31/24)

	1 Year	5 Years	10 Years
Institutional Class Return Before Taxes	22.08%	15.96%	11.16%
Institutional Class Return After Taxes on Distributions(1)	20.91%	11.50%	8.51%
Institutional Class Return After Taxes on Distributions and Sales of Fund Shares(1)	13.46%	11.13%	8.13%
I-2 Return Before Taxes	21.90%	15.83%	11.04%
Class A Return Before Taxes	16.92%	14.59%	10.29%
S&P 500 Index (reflects no deductions for fees, expenses or taxes)	25.02%	14.53%	13.10%
Russell 2000® Value Index (reflects no deductions for fees, expenses or taxes)	8.06%	7.29%	7.14%
Russell 2000® Index (reflects no deductions for fees, expenses or taxes)	11.54%	7.40%	7.82%

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. Syzygy Asset Management serves as the Fund's sub-adviser. The Fund’s portfolio is jointly and primarily managed by Rob Arnott and Jim Masturzo. Mr. Arnott is Chairman and Founder of Syzygy Asset Management. Mr. Masturzo is the Chief Investment Officer of Syzygy Asset Management. Mr. Arnott has managed the Fund since its inception in June 2015. Mr. Masturzo has managed the Fund since November 2025.

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 and Class I-2

The minimum initial investment for Institutional and Class I-2 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 and Class I-2 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:

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Sending a written request by regular mail to:

PIMCO Equity Series
P.O. Box 219024, Kansas City, MO 64121-9024
or by overnight mail to:
PIMCO Equity Series c/o SS&C Global Investor and Distribution Solutions, Inc.
801 Pennsylvania Avenue, Ste 219024 Kansas City, MO 64105-1307

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Calling us at 1.888.87.PIMCO and a Shareholder Services associate will assist you

■

Sending a fax to our Shareholder Services department at 1.816.421.2861

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Sending an e-mail to piprocess@sscinc.com

Class A

The minimum initial investment for Class A shares of the Fund is $1,000. The minimum subsequent investment for Class A 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 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 Equity Series, P.O. Box 219294, Kansas City, MO 64121-9294 or overnight mail to PIMCO Equity Series, c/o SS&C Global Investor and Distribution Solutions, Inc., 801 Pennsylvania Avenue, Ste 219294, Kansas City, MO 64105-1307. 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.

4 Summary Prospectus | PIMCO Equity Series