PIMCO Dynamic Income Fund (PDI) N-CSR/ACertified annual shareholder report (management investment company) (amended)

As of the date of this report, interest rates in the United States and many parts of the world, including certain European countries, are ascending from historically low levels. Thus, bond funds currently face a heightened level of risk associated with rising interest rates and/or bond yields. This could be driven by a variety of factors, including but not limited to central bank monetary policies, changing inflation or real growth rates, general economic conditions, increasing bond issuances or reduced market demand for low yielding investments. Further, while bond markets have steadily grown over the past three decades, dealer inventories of corporate bonds are near historic lows in relation to market size. As a result, there has been a significant reduction in the ability of dealers to “make markets”.

Bond funds and individual bonds with a longer duration (a measure used to determine the sensitivity of a security’s price to changes in interest rates) tend to be more sensitive to changes in interest rates, usually making them more volatile than securities or funds with shorter durations. All of the factors mentioned above, individually or collectively, could lead to increased volatility and/or lower liquidity in the fixed income markets or negatively impact a Fund’s performance or cause a Fund to incur losses.

A Fund may enter into opposite sides of multiple interest rate swaps or other derivatives with respect to the same underlying reference instrument (e.g., aU.S. treasury) that have different effective dates with respect to interest accrual time periods also for the principal purpose of generating distributable gains (characterized as ordinary income for tax purposes) that are not part of a Fund’s duration or yield curve management strategies. In such a “paired swap transaction”, a Fund would generally enter into one or more interest rate swap agreements whereby a Fund agrees to make regular payments starting at the time a Fund enters into the agreements equal to a floating interest rate in return for payments equal to a fixed interest rate (the “initial leg”). A Fund would also enter into one or more interest rate swap agreements on the same underlying instrument, but take the opposite position (i.e., in this example, a Fund would make regular payments equal to a fixed interest rate in return for receiving payments equal to a floating interest rate) with respect to a contract whereby the payment obligations do not commence until a date following the commencement of the initial leg (the “forward leg”).

A Fund may engage in investment strategies, including those that employ the use of paired swaps transactions, the use of interest rate swaps to seek to capitalize on differences between short-term and long-term interest rates and other derivatives transactions, to, among other things, seek to generate current, distributable income, even if such strategies could potentially result in declines in the Fund’s net asset value (“NAV”). A Fund’s income and gain-generating strategies, including certain derivatives strategies, may generate current income and gains taxable as ordinary income sufficient to support monthly distributions even in situations when a Fund has experienced a decline in net assets due to, for example, adverse changes in the broad U.S. or non-U.S. equity markets or a Fund’s debt investments, or arising from

The Funds may invest in certain instruments that rely in some fashion upon the London Interbank Offered Rate (“LIBOR”). LIBOR is an average interest rate, determined by the ICE Benchmark Administration, that banks charge one another for the use of short-term money. The United Kingdom’s Financial Conduct Authority, which regulates LIBOR, has announced plans to ultimately phase out the use of LIBOR. The transition may result in a reduction in the value of certain instruments held by a Fund or a reduction in the effectiveness of related Fund transactions such as hedges. There remains uncertainty regarding future utilization of LIBOR and the nature of any replacement rate (e.g., the Secured Overnight Financing Rate, which is intended to replace U.S. dollar LIBOR and measures the cost of overnight borrowings through repurchase agreement transactions collateralized with U.S. Treasury securities). Any potential effects of the transition away from LIBOR on a Fund or on certain instruments in which a Fund invests can be difficult to ascertain, and they may vary depending on a variety of factors. The transition may also result in a reduction in the value of certain instruments held by a Fund or a reduction in the effectiveness of related Fund transactions such as hedges. Any such effects of the transition away from LIBOR, as well as other unforeseen effects, could result in losses to a Fund.

The common shares of the Funds trade on the New York Stock Exchange. As with any stock, the price of a Fund’s common shares will fluctuate with market conditions and other factors. If you sell your common shares of a Fund, the price received may be more or less than your original investment. Shares of closed-end management investment companies, such as the Funds, frequently trade at a discount from their NAV and may trade at a price that is less than the initial offering price and/or the NAV of such shares. Further, if a Fund’s shares trade at a price that is more than the initial offering price and/or the NAV of such shares, including at a substantial premium and/or for an extended period of time, there is no assurance that any such premium will be sustained for any period of time and will not decrease, or that the shares will not trade at a discount to NAV thereafter.

On each Fund Summary page in this Shareholder Report, the Average Annual Total Return table measures performance assuming that all dividend and capital gain distributions were reinvested. Total return is calculated by determining the percentage change in NAV or market price (as applicable) in the specified period. Returns do not reflect the deduction of taxes that a shareholder would pay on Fund distributions. Total return for a period of more than one year represents the average annual total return. Performance at market price will differ from results at NAV. Although market price returns tend to reflect investment results over time, during shorter periods returns at market price can also be influenced by factors such as changing views about a Fund, market conditions, supply and demand for the Fund’s shares, or changes in the Fund’s dividends. Performance shown is net of fees and expenses. Historical NAV performance for a Fund may have been positively impacted by fee waivers or expense limitations in place during some or all of the periods shown, if applicable. Future performance (including total return or yield) and distributions may be negatively impacted by the expiration or reduction of any such fee waivers or expense limitations.

fundamental investment policies) or where a shareholder approval requirement was specifically disclosed in a Fund’s then-current prospectus, SAI or shareholder report and is otherwise still in effect.

PIMCO has adopted written proxy voting policies and procedures (“Proxy Policy”) as required by Ruleunder the Investment Advisers Act of 1940, as amended. The Proxy Policy has been adopted by the Funds as the policies and procedures that PIMCO will use when voting proxies on behalf of the Funds. A description of the policies and procedures that PIMCO uses to vote proxies relating to portfolio securities of each Fund, and information about how each Fund voted proxies relating to portfolio securities held during the most recent twelve-month period ended June 30th, are available without charge, upon request, by calling the Funds at (844)on the Funds’ website at www.pimco.com, and on the Securities and Exchange Commission’s (“SEC”) website at www.sec.gov.

The Funds file portfolio holdings information with the SEC onwithin 60 days of the end of each fiscal quarter. The Funds’ complete schedules of securities holdings as of the end of each fiscal quarter will be made available to the public on the SEC’s website at www.sec.gov and on PIMCO’s website at www.pimco.com, and will be made available, upon request, by calling PIMCO at (844) 33-PIMCO.

SEC rules allow shareholder reports to be delivered to investors by providing access to such reports online free of charge and by mailing a notice that the report is electronically available. Investors may elect to receive all reports in paper free of charge by contacting their financial intermediary or, if invested directly with a Fund, investors can inform the Fund by calling (844) 33-PIMCO. Any election to receive reports in paper will apply to all funds held with the fund complex if invested directly with a Fund or to all funds held in the investor’s account if invested through a financial intermediary, such as a broker-dealer or bank.

In April 2020, the SEC adopted amended rules modifying the registration, communications, and offering processes for registered closed-end funds and interval funds. Among other things, the amendments: (1) permit qualifying closed-end funds to use a short-form registration statement to offer securities in eligible transactions and certain funds to qualify as Well Known Seasoned Issuers; (2) permit interval funds to pay registration fees based on net issuance of shares in a manner similar to mutual funds; (3) require closed-end funds and interval funds to include additional disclosures in their annual reports; and (4) require certain information to be filed in interactive data format. The new rules have phased compliance dates, with some requirements having already taken effect and others requiring compliance as late as February 1, 2023.

In October 2020, the SEC adopted a rule related to the use of derivatives, short sales, reverse repurchase agreements and certain

three pre-defined classifications (i.e., integrated, ESG focused and/or impact funds) provide prospectus and shareholder report disclosure related to the ESG factors, criteria and processes used in managing the fund. The proposal’s impact on the Funds will not be known unless and until any final rulemaking is adopted.

The following example illustrates the expenses that you would pay on a $1,000 investment in Common Shares of the Fund, assuming (1) that the Fund’s net assets do not increase or decrease, (2) that the Fund incurs total annual expenses of 2.64% of net assets attributable to Common Shares in years 1 through 10 (assuming assets attributable to reverse repurchase agreements representing 54.93% of the Fund’s total managed assets) and (3) a 5% annual return: