PIMCO CORPORATE & INCOME OPPORTUNITY FUND

(Name and Address (Number, Street, City, State, Zip Code) of Agent for Service)

If any securities being registered on this form will be offered on a delayed or continuous basis in reliance on Rule 415 under the Securities Act of 1933, other than securities offered in connection with a dividend reinvestment plan, check the following box [X].

The registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment that specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until this Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

Base Prospectus

Neither the U.S. Securities and Exchange Commission nor the U.S. Commodity Futures Trading Commission has approved or disapproved these securities, or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.


	Subject to completion, dated June 8, 2018

	Common Shares
PIMCO Corporate & Income Opportunity Fund	PTY

PIMCO Corporate & Income Opportunity Fund (the "Fund") is a diversified, closed-end management investment company that commenced operations on December 27, 2002, following the initial public offering of its common shares.

Investment Objective. The Fund's investment objective is to seek maximum total return through a combination of current income and capital appreciation.

Investment Strategy. The Fund seeks to achieve its investment objective by utilizing a dynamic asset allocation strategy that focuses on duration management, credit quality analysis, risk management techniques and broad diversification among issuers, industries and sectors. The Fund normally invests in a portfolio that consists primarily of corporate debt obligations of varying maturities, other corporate income-producing securities, and income-producing securities of non-corporate issuers. On behalf of the Fund, Pacific Investment Management Company LLC, the Fund's investment manager ("PIMCO" or the "Investment Manager") employs an active approach to allocation among multiple fixed-income sectors based on, among other things, market conditions, valuation assessments and economic outlook, credit market trends and other economic factors. The Fund focuses on seeking the best income generating investment ideas across multiple fixed income sectors, with an emphasis on seeking opportunities in developed and emerging global credit markets.

Under normal circumstances, the Fund will have a short to intermediate average portfolio duration (i.e., within a zero to eight year range), as calculated by the Investment Manager, although it may be shorter or longer at any time or from time to time depending on market conditions and other factors. PIMCO believes that maintaining duration within this range offers flexibility and the opportunity for above-average returns while potentially limiting exposure to interest rate volatility and related risks.

Portfolio Contents. Under normal market conditions, the Fund seeks to achieve its investment objective by investing at least 80% of its total assets in a combination of corporate debt obligations of varying maturities, other corporate income-producing securities, and income-producing securities of non-corporate issuers, such as U.S. Government securities, municipal securities and mortgage-backed and other asset-backed securities issued on a public or private basis (the "80% Policy"). Corporate income-producing securities include fixed-, variable- and floating-rate bonds, debentures, notes and other similar types of corporate debt instruments, such as preferred shares, convertible securities, bank loans and loan participations and assignments, payment-in-kind securities, zero-coupon bonds, bank certificates of deposit, fixed time deposits and bankers' acceptances, stressed debt securities, structured notes and other hybrid instruments. The Fund normally invests at least 25% of its total assets in corporate debt obligations and other corporate income-producing securities. The Fund may invest in investment grade debt securities and below investment grade debt securities (commonly referred to as "high yield" securities or "junk bonds"), including securities of stressed issuers. The Fund may invest up to 25% of its total assets (measured at the time of investment) in non-U.S. dollar denominated securities (of both developed and "emerging market" countries). The Fund may invest without limit in investment grade sovereign debt denominated in the relevant country's local currency with less than 1 year remaining to maturity ("short-term investment grade sovereign debt"), including short-term investment grade sovereign debt issued by emerging market issuers. The Fund may invest up to 40% of its total assets in securities and instruments that are economically tied to "emerging market" countries other than investments in short-term investment grade sovereign debt issued by emerging market issuers, where as noted above there is no limit. The Fund may also invest directly in foreign currencies, including local emerging market currencies.

The Fund may, but is not required to, utilize various derivative strategies (both long and short positions) involving the purchase or sale of futures and forward contracts (including foreign currency exchange contracts), call and put options, credit default swaps, total return swaps, basis swaps and other swap agreements and other derivative instruments for investment purposes, leveraging purposes or in an attempt to hedge against market, credit, interest rate, currency and other risks in the portfolio. The Fund may purchase and sell securities on a when-issued, delayed delivery or forward commitment basis and may engage in short sales.

The Fund may invest in securities that have not been registered for public sale in the U.S. or relevant non-U.S. jurisdictions, including without limit securities eligible for purchase and sale pursuant to Rule 144A under the Securities Act of 1933, as amended (the "1933 Act"), or relevant provisions of applicable non-U.S. law, and other securities issued in private placements. The Fund may also invest in securities of other open- and closed-end investment companies, including, without limit, exchange-traded funds ("ETFs"), and may invest in foreign ETFs. The Fund may invest in real estate investment trusts ("REITs"). The Fund may invest in securities of companies with any market capitalization, including small and medium capitalizations.

The Fund may invest up to 20% of its total assets in illiquid securities (i.e., securities that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the security).

Leverage. The Fund utilizes leverage through its outstanding auction rate preferred shares ("ARPS" and, together with any other preferred shares the Fund may have outstanding, "Preferred Shares") and may obtain additional leverage through the use of reverse repurchase agreements, dollar rolls or borrowings, such as through bank loans or commercial paper and/or other credit facilities. The Fund may also enter into transactions other than those noted above that may give rise to a form of leverage including, among others, credit default swaps, futures and forward contracts (including foreign currency exchange contracts), total return swaps and other

derivative transactions, loans of portfolio securities, short sales and when-issued, delayed delivery and forward commitment transactions. Although it has no current intention to do so, the Fund may also determine to issue other types of preferred shares. Depending upon market conditions and other factors, the Fund may or may not determine to add leverage following an offering to maintain or increase the total amount of leverage (as a percentage of the Fund's total assets) that the Fund currently maintains, taking into account the additional assets raised through the issuance of Common Shares in such offering. The Fund utilizes certain kinds of leverage, such as reverse repurchase agreements and credit default swaps, opportunistically and may choose to increase or decrease, or eliminate entirely, its use of such leverage over time and from time to time based on PIMCO's assessment of the yield curve environment, interest rate trends, market conditions and other factors. The Fund may also determine to decrease the leverage it currently maintains through its outstanding Preferred Shares through Preferred Share redemptions or tender offers and may or may not determine to replace such leverage through other sources. If the Fund determines to add leverage following an offering, it is not possible to predict with accuracy the precise amount of leverage that would be added, in part because it is not possible to predict the number of Common Shares that ultimately will be sold in an offering or series of offerings. To the extent that the Fund does not add additional leverage following an offering, the Fund's total amount of leverage as a percentage of its total assets will decrease, which could result in a reduction of investment income available for distribution to holders of the Fund's Common Shares ("Common Shareholders"). The Fund will not incur leverage (including through preferred shares and other forms of leverage) in an amount exceeding 50% of its total assets. Leveraging is a speculative technique and there are special risks and costs involved. There can be no assurance that a leveraging strategy will be used or that it will be successful during any period in which it is employed. See "Use of Leverage" and "Principal Risks of the Fund—Leverage Risk"

This prospectus is part of a registration statement that the Fund has filed with the U.S. Securities and Exchange Commission (the "SEC"), using the "shelf" registration process. The Fund may offer, from time to time, in one or more offerings, up to $229,680,000 of the Common Shares on terms to be determined at the time of the offering. This prospectus provides you with a general description of the Common Shares that the Fund may offer. Each time the Fund uses this prospectus to offer Common Shares, the Fund will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement may also add, update or change information contained in this prospectus. You should read this prospectus and the applicable prospectus supplement, which contain important information about the Fund, carefully before you invest in the Common Shares. Common Shares may be offered directly to one or more purchasers, through agents designated from time to time by the Fund, or to or through underwriters or dealers. The prospectus supplement relating to an offering will identify any agents, underwriters or dealers involved in the sale of Common Shares, and will set forth any applicable purchase price, fee, commission or discount arrangement between the Fund and its agents or underwriters, or among the Fund's underwriters, or the basis upon which such amount may be calculated. See "Plan of Distribution." The Fund may not sell any Common Shares through agents, underwriters or dealers without delivery or deemed delivery of a prospectus supplement describing the method and terms of the particular offering of the Common Shares. You should retain this prospectus and any prospectus supplement for future reference. A Statement of Additional Information, dated June [ ], 2018, containing additional information about the Fund has been filed with the SEC and is incorporated by reference in its entirety into this prospectus. You can review the table of contents of the Statement of Additional Information on page 88 of this prospectus. You may request a free copy of the Statement of Additional Information, request the Fund's most recent annual and semiannual reports, request information about the Fund and make shareholder inquiries by calling toll-free (844)-337-4626 or by writing to the Fund at c/o Pacific Investment Management Company LLC, 1633 Broadway, New York, New York 10019. You may also obtain a copy of the Statement of Additional Information (and other information regarding the Fund) from the SEC's Public Reference Room in Washington, D.C. by calling (202) 551-8090. The SEC charges a fee for copies. The Fund's Statement of Additional Information and most recent annual and semiannual reports are available, free of charge, on the Fund's website (http://www.pimco.com). You can obtain the same information, free of charge, from the SEC's website (http://www.sec.gov).

The Common Shares do not represent a deposit or obligation of, and are not guaranteed or endorsed by, any bank or other insured depository institution, and are not federally insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency.

You should rely only on the information contained or incorporated by reference in this prospectus. The Fund has not authorized anyone to provide you with inconsistent information. If anyone provides you with inconsistent information, you should not assume that the Fund has authorized or verified it. The Fund is not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information contained in this prospectus is accurate as of any date other than the date on the front of this prospectus. The Fund's business, financial condition, results of operations and prospects may have changed since that date.

The Fund's common shares (the "Common Shares") are listed on the New York Stock Exchange ("NYSE") under the symbol "PTY." The last reported sale price of the Common Shares, as reported by the NYSE on January 31, 2018, was $16.43 per Common Share. The net asset value ("NAV") of the Common Shares at the close of business on January 31, 2018, was $15.03 per Common Share.

Investment in the Fund's common shares involves substantial risks arising from, among other strategies, the Fund's ability to invest in debt instruments that are, at the time of purchase, rated below investment grade (below Baa3 by Moody's Investors Service, Inc. ("Moody's") or below BBB- by either S&P Global Ratings, a division of S&P Global Inc. ("S&P"), or Fitch, Inc. ("Fitch")) or unrated but determined by PIMCO to be of comparable quality, the Fund's exposure to foreign and emerging markets securities and currencies and to mortgage-related and other asset-backed securities, and the Fund's use of leverage. Debt securities of below investment grade quality are regarded as having predominantly speculative characteristics

with respect to capacity to pay interest and to repay principal, and are commonly referred to as "high yield" securities or "junk bonds." The Fund's exposure to foreign securities and currencies, and particularly to emerging markets securities and currencies, involves special risks, including foreign currency risk and the risk that the securities may decline in response to unfavorable political and legal developments, unreliable or untimely information or economic and financial instability. Mortgage-related and other asset-backed securities are subject to extension and prepayment risk and often have complicated structures that make them difficult to value. Because of the risks associated with investing in high yield securities, foreign and emerging market securities (and related exposure to foreign currencies) and mortgage-related and other asset-backed securities, and using leverage, an investment in the Fund should be considered speculative. Before investing in the Common Shares, you should read the discussion of the principal risks of investing in the Fund in "Principal Risks of the Fund." Certain of these risks are summarized in "Prospectus Summary—Principal Risks of the Fund." The Fund cannot assure you that it will achieve its investment objective, and you could lose all of your investment in the Fund.

This is only a summary. This summary may not contain all of the information that you should consider before investing in the Fund's common shares of beneficial interest (the "Common Shares"). You should review the more detailed information contained in this prospectus and in any related prospectus supplement and in the Statement of Additional Information, especially the information set forth under the heading "Principal Risks of the Fund."

PIMCO Corporate & Income Opportunity Fund (the "Fund") is a diversified, closed-end management investment company. The Fund commenced operations on December 27, 2002, following the initial public offering of its Common Shares. Effective February 1, 2012, the Fund changed its name from PIMCO Corporate Opportunity Fund to its current name, PIMCO Corporate & Income Opportunity Fund.

The Common Shares are listed on the New York Stock Exchange ("NYSE") under the symbol "PTY." As of January 31, 2018, the net assets of the Fund attributable to Common Shares were $1,217,573,672 and the Fund had outstanding 81,003,790 Common Shares and 9,518 auction rate preferred shares of beneficial interest ("ARPS" and, together with any other preferred shares issued by the Fund, "Preferred Shares"). The last reported sale price of the Common Shares, as reported by the NYSE on January 31, 2018, was $16.43 per Common Share. The net asset value ("NAV") of the Common Shares at the close of business on January 31, 2018, was $15.03 per Common Share. See "Description of Capital Structure."

The Fund may offer, from time to time, in one or more offerings, up to $229,680,000 of the Common Shares on terms to be determined at the time of the offering. The Common Shares may be offered at prices and on terms to be set forth in one or more prospectus supplements. You should read this prospectus and the applicable prospectus supplement carefully before you invest in the Common Shares. Common Shares may be offered directly to one or more purchasers, through agents designated from time to time by the Fund, or to or through underwriters or dealers. The prospectus supplement relating to an offering will identify any agents, underwriters or dealers involved in the sale of Common Shares, and will set forth any applicable purchase price, fee, commission or discount arrangement between the Fund and its agents or underwriters, or among the Fund's underwriters, or the basis upon which such amount may be calculated. See "Plan of Distribution." The Fund may not sell any Common Shares through agents, underwriters or dealers without delivery or deemed delivery of a prospectus supplement describing the method and terms of the particular offering of the Common Shares.

The Fund's investment objective is to seek maximum total return through a combination of current income and capital appreciation. The Fund will seek to achieve its investment objective by utilizing a dynamic asset allocation strategy among multiple fixed-income sectors in the global credit markets, including corporate debt (including, among other things, fixed-, variable- and floating-rate bonds, bank loans, convertible securities and stressed debt securities issued by U.S. or foreign (non-U.S.) corporations or other business entities, including emerging market issuers), mortgage-related and other asset-backed securities, government and sovereign debt, taxable municipal bonds and other fixed-, variable- and floating-rate income-producing securities of U.S. and foreign issuers, including emerging market issuers. The Fund may invest in investment grade debt securities and below investment grade debt securities (commonly referred to as "high yield" securities or "junk bonds"), including securities of stressed issuers. The types of securities and instruments in which the Fund may invest are summarized under "Portfolio Contents" below. The Fund cannot assure you that it will achieve its investment objective, and you could lose all of your investment in the Fund.

Dynamic Allocation Strategy. On behalf of the Fund, the Fund's investment manager, Pacific Investment Management Company LLC ("PIMCO" or the "Investment Manager"), employs an active approach to allocation among multiple fixed income sectors based on, among other things, market conditions, valuation assessments, economic outlook, credit market trends and other economic factors. With PIMCO's macroeconomic analysis as the basis for top-down investment decisions, including geographic and credit sector emphasis, the Fund focuses on seeking the best income generating investment ideas across multiple fixed income sectors, with an emphasis on seeking opportunities in developed and emerging global credit markets. PIMCO may choose to focus on particular countries/regions (e.g., U.S. vs. foreign), asset classes, industries and sectors to the exclusion of others at any time and from time to time based on market conditions and other factors. The relative value assessment within fixed-income sectors draws on PIMCO's regional and sector specialist expertise. The Fund will observe various investment guidelines as summarized below.

Investment Selection Strategies. Once the Fund's top-down, portfolio positioning decisions have been made as described above, PIMCO selects particular investments for the Fund by employing a bottom-up, disciplined credit approach which is driven by fundamental, independent research within each sector/asset class represented in the Fund, with a focus on identifying securities and other instruments with solid and/or improving fundamentals.

PIMCO utilizes strategies that focus on credit quality analysis, duration management and other risk management techniques. PIMCO attempts to identify, through fundamental research driven by independent credit analysis and proprietary analytical tools, debt obligations and other income-producing securities that provide current income and/or opportunities for capital appreciation based on its analysis of the issuer's credit characteristics and the position of the security in the issuer's capital structure.

Consideration of yield is only one component of the portfolio managers' approach in managing the Fund. PIMCO also attempts to identify investments that may appreciate in value based on PIMCO's assessment of the issuer's credit characteristics, forecast for interest rates and outlook for particular countries/regions, currencies, industries, sectors and the global economy and bond markets generally.

Credit Quality. The Fund may invest in debt instruments that are, at the time of purchase, rated below investment grade, or unrated but determined by PIMCO to be of comparable quality. The Fund will not normally invest more than 20% of its total assets in debt instruments, other than mortgage-related and other asset-backed securities, that are, at the time of purchase, rated CCC or lower by S& P Global Ratings ("S&P") and Fitch, Inc. ("Fitch") and Caa1 or lower by Moody's Investors Services Inc. ("Moody's"), or that are unrated but determined by PIMCO to be of comparable quality to securities so rated. The Fund may invest without limit in mortgage-related and other asset-backed securities regardless of rating (i.e., of any credit quality). Subject to this 20% restriction, the Fund may invest in issuers of any credit quality (including bonds in the lowest ratings categories) if PIMCO determines that the particular obligation is undervalued or offers an attractive yield relative to its risk profile. The Fund may also invest up to 5% of its total assets in defaulted bonds when PIMCO believes that the issuer's potential revenues and prospects for recovery are favorable, except that the Fund may invest in mortgage-related and other asset-backed securities without regard to this limit, subject to the Fund's other investment policies. For purposes of applying the foregoing policies, in the case of securities with split ratings (i.e., a security receiving two different ratings from two different rating agencies), the Fund will apply the higher of the applicable ratings. Subject to the aforementioned investment restrictions, the Fund may invest in securities of stressed issuers, which include securities at risk of being in default as to the repayment of principal and/or interest at the time of acquisition by the Fund or that are rated in the lower rating categories by one or more nationally recognized statistical rating organizations (for example, Ca or lower by Moody's or CC or lower by S&P or Fitch) or, if unrated, are determined by PIMCO to be of comparable quality. Debt instruments of below investment grade quality are regarded as having predominantly speculative characteristics with respect to capacity to pay interest and to repay principal, and are commonly referred to as "high yield" securities or "junk bonds." Debt instruments in the lowest investment grade category also may be considered to possess some speculative characteristics. The Fund may, for hedging, investment or leveraging purposes, make use of credit default swaps, which are contracts whereby one party makes periodic payments to a counterparty in exchange for the right to receive from the counterparty a payment equal to the par (or other agreed-upon) value of a referenced debt obligation in the event of a default or other credit event by the issuer of the debt obligation. In addition, the Fund's use of credit default swaps and certain other derivative instruments will be limited by the Fund's 20% limit on illiquid investments to the extent they are determined to be illiquid.

Independent Credit Analysis. PIMCO relies primarily on its own analysis of the credit quality and risks associated with individual debt instruments considered for the Fund, rather than relying exclusively on rating agencies or third-party research. The Fund's portfolio managers utilize this information in an attempt to minimize credit risk and to identify issuers, industries or sectors that are undervalued or that offer attractive yields relative to PIMCO's assessment of their credit characteristics. This aspect of PIMCO's capabilities will be particularly important to the extent that the Fund invests in high yield securities and in securities of emerging market issuers.

Duration Management. It is expected that the Fund normally will have a short to intermediate average portfolio duration (i.e., within a zero to eight year (0 to 8) range), as calculated by PIMCO, although it may be shorter or longer at any time or from time to time depending on market conditions and other factors. While the Fund seeks to maintain a short to intermediate average portfolio duration, there is no limit on the maturity or duration of any individual security in which the Fund may invest. PIMCO believes that maintaining duration within this range offers flexibility and the opportunity for above-average returns while potentially limiting exposure to interest rate volatility and related risk. Duration is a measure used to determine the sensitivity of a security's price to changes in interest rates. The Fund's duration strategy may entail maintaining a negative average portfolio duration from time to time, which would potentially benefit the portfolio in an environment of rising market interest rates, but would generally adversely impact the portfolio in an environment of falling or neutral market interest rates. PIMCO may also utilize certain strategies, including without limit investments in structured notes or interest rate futures contracts or swap, cap, floor or collar transactions, for the purpose of reducing the interest rate sensitivity of the Fund's portfolio, although there is no assurance that it will do so or that such strategies will be successful.

zero-coupon bonds, bank certificates of deposit, fixed time deposits and bankers' acceptances, stressed debt securities, structured notes and other hybrid instruments. Certain corporate income-producing securities, such as convertible bonds, also may include the right to participate in equity appreciation, and PIMCO will generally evaluate those instruments based primarily on their debt characteristics. In satisfying the Fund's 80% Policy, the Fund may invest in mortgage-related securities, including mortgage pass-through securities, collateralized mortgage obligations ("CMOs"), commercial or residential mortgage-backed securities, mortgage dollar rolls, CMO residuals, stripped mortgage-backed securities ("SMBSs") and other securities that directly or indirectly represent a participation in, or are secured by and payable from, mortgage loans on real property, debt instruments, including, without limitation, bonds, debentures, notes, and other debt securities of U.S. and foreign (non-U.S.) corporate and other issuers, including commercial paper; obligations of foreign governments or their sub-divisions, agencies and government sponsored enterprises and obligations of international agencies and supranational entities; municipal securities and other debt securities issued by states or local governments and their agencies, authorities and other government-sponsored enterprises, including taxable municipal securities (such as Build America Bonds); inflation-indexed bonds issued by both governments and corporations; structured notes, including hybrid or indexed securities; catastrophe bonds and other event-linked bonds; credit-linked notes; structured credit products; bank loans (including, among others, senior loans, delayed funding loans, revolving credit facilities and loan participations and assignments); preferred securities and convertible debt securities (i.e., debt securities that may be converted at either a stated price or stated rate into underlying shares of common stock), including synthetic convertible debt securities (i.e., instruments created through a combination of separate securities that possess the two principal characteristics of a traditional convertible security, such as an income-producing security and the right to acquire an equity security) and contingent convertible securities. The Fund may invest in debt securities of stressed issuers. Subject to the investment limitations described under "Credit Quality" above, at any given time and from time to time, substantially all of the Fund's portfolio may consist of below investment grade securities. The Fund may invest in any level of the capital structure of an issuer of mortgage-backed or asset-backed securities, including the equity or "first loss" tranche. The rate of interest on an income-producing security may be fixed, floating or variable.

The Fund may invest up to 25% of its total assets (measured at the time of investment) in non-U.S. dollar denominated securities (of both developed and "emerging market" countries), including obligations of non-U.S. governments and their respective sub-divisions, agencies and government-sponsored enterprises. The Fund may invest without limit in investment grade sovereign debt denominated in the relevant country's local currency with less than 1 year remaining to maturity ("short-term investment grade sovereign debt"), including short-term investment grade sovereign debt issued by emerging market issuers. The Fund may invest up to 40% of its total assets in securities and instruments that are economically tied to "emerging market" countries other than investments in short-term investment grade sovereign debt issued by emerging market issuers, where as noted above there is no limit. The Fund may also invest directly in foreign currencies, including local emerging market currencies.

The Fund may invest in securities that have not been registered for public sale in the U.S. or relevant non-U.S. jurisdictions, including without limit securities eligible for purchase and sale pursuant to Rule 144A under the 1933 Act, or relevant provisions of applicable non-U.S. law, and other securities issued in private placements. The Fund may also invest in securities of other open- and closed-end investment companies, including, without limit, exchange-traded funds ("ETFs"), and may invest in foreign ETFs. The Fund may invest in real estate investment trusts ("REITs"). The Fund may invest in securities of companies with any market capitalization, including small and medium capitalizations.

The Fund utilizes leverage through its outstanding Preferred Shares and may obtain additional leverage through reverse repurchase agreements, dollar rolls or borrowings, such as through bank loans or commercial paper and/ or other credit facilities. The amount of leverage the Fund utilizes may vary, but the Fund will not incur leverage (including Preferred Shares and other forms of leverage) in an amount exceeding 50% of its total assets. Information regarding the terms and features of the ARPS is provided under "Description of Capital Structure" in this Prospectus.

The Fund may also enter into transactions other than those noted above that may give rise to a form of leverage including, among others, credit default swaps, futures and forward contracts (including foreign currency exchange contracts), total return swaps and other derivative transactions, loans of portfolio securities, short sales and when-issued, delayed delivery and forward commitment transactions. Although it has no current intention to do so, the Fund may also determine to issue other types of preferred shares.

and credit default swaps, opportunistically and may choose to increase or decrease, or eliminate entirely, its use of such leverage over time and from time to time based on PIMCO's assessment of the yield curve environment, interest rate trends, market conditions and other factors. The Fund may also determine to decrease the leverage it currently maintains through its outstanding Preferred Shares through Preferred Shares redemptions or tender offers and may or may not determine to replace such leverage through other sources. If the Fund determines to add leverage following an offering, it is not possible to predict with accuracy the precise amount of leverage that would be added, in part because it is not possible to predict the number of Common Shares that ultimately will be sold in an offering or series of offerings. To the extent that the Fund does not add additional leverage following an offering, the Fund's total amount of leverage as a percentage of its total assets will decrease, which could result in a reduction of investment income available for distribution to holders of the Fund's Common Shares ("Common Shareholders").

The Fund's net assets attributable to its Preferred Shares and the net proceeds the Fund obtains from reverse repurchase agreements or other forms of leverage utilized, if any, will be invested in accordance with the Fund's investment objective and policies as described in this prospectus and any prospectus supplement. So long as the rate of return, net of applicable Fund expenses, on the debt obligations and other investments purchased by the Fund exceeds the dividend rates payable on the Preferred Shares together with the costs to the Fund of other leverage it utilizes, the investment of the Fund's net assets attributable to leverage will generate more income than will be needed to pay the costs of the leverage. If so, and all other things being equal, the excess may be used to pay higher dividends to Common Shareholders than if the Fund were not so leveraged.

Regarding the costs associated with the Fund's ARPS, the terms of the ARPS provide that they would ordinarily pay dividends at a rate set at auctions held every seven days, normally payable on the first business day following the end of the rate period, subject to a maximum applicable rate calculated as a function of the ARPS' then-current rating and a reference interest rate. However, the weekly auctions for the ARPS, as well as auctions for similar preferred shares of other closed-end funds in the U.S., have failed since February 2008, and the dividend rates on the ARPS since that time have been paid at the maximum applicable rate (i.e., a multiple of a reference rate, which is the applicable "AA" Financial Composite Commercial Paper Rate (for a dividend period of fewer than 184 days) or the applicable Treasury Index Rate (for a dividend period of 184 days or more)). In September 2011, Moody's, a ratings agency that provides ratings for the Fund's ARPS, downgraded its rating of the ARPS from "Aaa" to "A2," citing persistently thin asset coverage levels, increased NAV volatility and concerns about secondary market liquidity for some assets supporting rated obligations. In July 2012, Moody's downgraded its rating of the ARPS from "A2" to "A3" pursuant to a revised ratings methodology adopted by Moody's. Also, in May 2014, Moody's upgraded its rating of the Fund's ARPS from A3 to A2, citing changes in the Fund's asset coverage ratio and economic leverage. Under the Fund's amended and restated bylaws (the "Bylaws"), the 2011 downgrade resulted in an increase in the multiple used to calculate the maximum applicable rate from 150% to 200%, thereby increasing the dividend rate payable to ARPS holders and increasing the costs to Common Shareholders associated with the Fund's leverage. See "Use of Leverage" and "Description of Capital Structure." The Fund expects that the ARPS will continue to pay dividends at the maximum applicable rate for the foreseeable future and cannot predict whether or when the auction markets for the ARPS may resume normal functioning. See "Use of Leverage," "Principal Risks of the Fund—Leverage Risk," "Principal Risks of the Fund—Additional Risks Associated with the Fund's Preferred Shares" and "Description of Capital Structure" for more information.

Under the Investment Company Act of 1940, as amended (the "1940 Act"), and the rules and regulations thereunder, the Fund is not permitted to issue new preferred shares unless immediately after such issuance the value of the Fund's total net assets (as defined below) is at least 200% of the liquidation value of the outstanding Preferred Shares and the newly issued preferred shares plus the aggregate amount of any senior securities of the Fund representing indebtedness (i.e., such liquidation value plus the aggregate amount of senior securities representing indebtedness may not exceed 50% of the Fund's total net assets). In addition, the Fund is not permitted to declare any cash dividend or other distribution on its Common Shares unless, at the time of such declaration, the value of the Fund's total net assets satisfies the above-referenced 200% coverage requirement.

The 1940 Act also generally prohibits the Fund from engaging in most forms of leverage representing indebtedness other than preferred shares (including the use of reverse repurchase agreements, dollar rolls, bank loans, commercial paper or other credit facilities, credit default swaps, total return swaps and other derivative transactions, loans of portfolio securities, short sales and when-issued, delayed delivery and forward commitment transactions, to the extent that these instruments are not covered as described below) unless immediately after the issuance of the leverage the Fund has satisfied the asset coverage test with respect to senior securities representing indebtedness prescribed by the 1940 Act; that is, the value of the Fund's total assets less all liabilities and indebtedness not represented by senior securities (for these purposes, "total net assets") is at least 300% of the senior securities representing indebtedness (effectively limiting the use of leverage through senior securities representing indebtedness to 33 1/3% of the Fund's total net assets, including assets attributable to such leverage). In addition, the Fund is not permitted to declare any cash dividend or other distribution on its Common Shares unless, at the time of such declaration, this asset coverage test is satisfied. The Fund may (but is not required to) cover its commitments under reverse repurchase agreements, dollar rolls, derivatives and certain other instruments by the segregation of liquid assets, or by entering into offsetting transactions or owning positions covering its obligations. To the extent that certain of these instruments are so covered, they will not be considered "senior securities" under the 1940 Act and therefore will not be subject to the 1940 Act 300% asset coverage requirement otherwise applicable to forms of senior securities representing indebtedness used by the Fund. However, reverse repurchase agreements and other such instruments, even if covered, represent a form of economic leverage and create special risks. The use of these forms of leverage increases the volatility of the Fund's investment portfolio and could result in larger losses to Common Shareholders than if these strategies were not used. See "Principal Risks of the Fund—Leverage Risk." To the extent that the Fund engages in borrowings, it may prepay a

portion of the principal amount of the borrowing to the extent necessary in order to maintain the required asset coverage. Failure to maintain certain asset coverage requirements could result in an event of default.

Leveraging is a speculative technique and there are special risks and costs involved. The Fund cannot assure you that its Preferred Shares and use of any other forms of leverage (such as the use of reverse repurchase agreements or derivatives strategies), if any, will result in a higher yield on your Common Shares. When leverage is used, the NAV and market price of the Common Shares and the yield to Common Shareholders will be more volatile. See "Principal Risks of the Fund—Leverage Risk." In addition, dividend, interest and other costs and expenses borne by the Fund with respect to its Preferred Shares and its use of any other forms of leverage are borne by the Common Shareholders (and not by the holders of Preferred Shares) and result in a reduction of the NAV of the Common Shares. In addition, because the fees received by the Investment Manager are based on the average daily net asset value of the Fund (including any assets attributable to any preferred shares), the Investment Manager has a financial incentive for the Fund to have preferred shares outstanding, which may create a conflict of interest between the Investment Manager, on the one hand, and the Common Shareholders, on the other hand. The fees received by the Investment Manager are not, however, charged on assets attributable to leverage obtained by the Fund other than through preferred shares.

The Fund's ability to utilize leverage is also limited by asset coverage requirements and other guidelines imposed by rating agencies (currently Moody's) that provide ratings for the Preferred Shares, which may be more restrictive than the limitations imposed by the 1940 Act noted above. See "Description of Capital Structure" for more information.

The Fund also may borrow money for temporary administrative purposes, to add leverage to the portfolio or for the settlement of securities transactions which otherwise might require untimely dispositions of portfolio securities held by the Fund.

Pacific Investment Management Company LLC ("PIMCO" or the "Investment Manager") serves as the investment manager of the Fund. Subject to the supervision of the Board of Trustees of the Fund (the "Board") PIMCO is responsible for managing the investment activities of the Fund and the Fund's business affairs and other administrative matters. Alfred Murata and Mohit Mittal are jointly and primarily responsible for the day-to-day management of the Fund.

The Investment Manager receives an annual fee from the Fund, payable monthly, in an amount equal to 0.650% of the Fund's average daily net assets, including daily net assets attributable to any preferred shares that may be outstanding. Average daily net assets means an average of all the determinations of the Fund's net assets (including net assets attributable to preferred shares) during a given month at the close of business on each business day during such month. PIMCO is located at 650 Newport Center Drive, Newport Beach, CA, 92660. Organized in 1971, PIMCO provides investment management and advisory services to private accounts of institutional and individual clients and to registered investment companies. PIMCO is a majority-owned indirect subsidiary of Allianz SE, a publicly traded European insurance and financial services company. As of March 31, 2018, PIMCO had approximately $1.77 trillion in assets under management.

The Fund makes regular monthly cash distributions to Common Shareholders at a rate based upon the past and projected net income of the Fund. Subject to applicable law, the Fund may fund a portion of its distributions with gains from the sale of portfolio securities and other sources. Distributions can only be made from net investment income after paying any accrued dividends to holders of the Preferred Shares. The dividend rate that the Fund pays on its Common Shares may vary as portfolio and market conditions change, and will depend on a number of factors, including without limit the amount of the Fund's undistributed net investment income and net short- and long-term capital gains, as well as the costs of any leverage obtained by the Fund (including the amount of the expenses and dividend rates on the Preferred Shares and any other preferred shares issued by the Fund and interest or other expenses on any reverse repurchase agreements, credit default swaps, dollar rolls and borrowings). As portfolio and market conditions change, the rate of distributions on the Common Shares and the Fund's dividend policy could change. For a discussion of factors that may cause the Fund's income and capital gains (and therefore the dividend) to vary, see "Principal Risks of the Fund." There can be no assurance that a change in market conditions or other factors will not result in a change in the Fund distribution rate or that the rate will be sustainable in the future.

The Fund generally distributes each year all of its net investment income and net short-term capital gains. In addition, at least annually, the Fund generally distributes net realized long-term capital gains not previously distributed, if any. The net investment income of the Fund consists of all income (other than net short-term and long-term capital gains) less all expenses of the Fund (after it pays accrued dividends on the outstanding Preferred Shares). The Fund may distribute less than the entire amount of net investment income earned in a particular period. The undistributed net investment income would be available to supplement future distributions. As a result, the distributions paid by the Fund for any particular monthly period may be more or less than the amount of net investment income actually earned by the Fund during the period. Undistributed net investment income will be additive to the Fund's NAV and, correspondingly, distributions from undistributed net investment income will be deducted from the Fund's NAV.

effectively a taxable return of the shareholder's investment in the Fund at a time when their investment in the Fund has declined in value, which tax may be at ordinary income rates. The tax treatment of certain derivatives in which the Fund invests may be unclear and thus subject to recharacterization. Any recharacterization of payments made or received by the Fund pursuant to derivatives potentially could affect the amount, timing or character of Fund distributions. In addition, the tax treatment of such investment strategies may be changed by regulation or otherwise.

To the extent required by the 1940 Act and other applicable laws, absent an exemption, a notice will accompany each monthly distribution with respect to the estimated source (as between net income and gains) of the distribution made. If the Fund estimates that a portion of one of its dividend distributions may be comprised of amounts from sources other than net income, in accordance with its policies and good accounting practices, the Fund will notify shareholders of record of the estimated composition of such distribution through a Section 19 Notice. For these purposes, the Fund estimates the source or sources from which a distribution is paid, to the close of the period as of which it is paid, in reference to its internal accounting records and related accounting practices. If, based on such accounting records and practices, it is estimated that a particular distribution does not include capital gains or paid-in surplus or other capital sources, a Section 19 Notice generally would not be issued. It is important to note that differences exist between the Fund's daily internal accounting records and practices, the Fund's financial statements presented in accordance with U.S. GAAP, and recordkeeping practices under income tax regulations. For instance, the Fund's internal accounting records and practices may take into account, among other factors, tax-related characteristics of certain sources of distributions that differ from treatment under U.S. GAAP. Examples of such differences may include, among others, the treatment of paydowns on mortgage-backed securities purchased at a discount and periodic payments under interest rate swap contracts. Accordingly, among other consequences, it is possible that the Fund may not issue a Section 19 Notice in situations where the Fund's financial statements prepared later and in accordance with U.S. GAAP and/or the final tax character of those distributions might later report that the sources of those distributions included capital gains and/or a return of capital.

The tax characterization of the Fund's distributions made in a taxable year cannot finally be determined until at or after the end of such taxable year. As a result, there is a possibility that the Fund may make total distributions during a taxable year in an amount that exceeds the Fund's net investment income and net realized capital gains for the relevant year (including as reduced by any capital loss carry-forwards). For example, the Fund may distribute amounts early in the year that are derived from short-term capital gains, but incur net short-term capital losses later in the year, thereby offsetting short-term capital gains out of which the Fund has already made distributions. In such a situation, the amount by which the Fund's total distributions exceed net investment income and net realized capital gains would generally be treated as a tax-free return of capital up to the amount of a shareholder's tax basis in his or her Common Shares, with any amounts exceeding such basis treated as gain from the sale of Common Shares. In general terms, a return of capital would occur where the Fund distribution (or portion thereof) represents a return of a portion of your investment, rather than net income or capital gains generated from your investment during a particular period. Although return of capital distributions are not taxable, such distributions would reduce the basis of a shareholder's Common Shares and therefore may increase a shareholder's capital gains, or decrease a shareholder's capital loss, thereby potentially increasing a shareholder's tax liability upon a sale of Common Shares. The Fund will prepare and make available to shareholders detailed tax information with respect to the Fund's distributions annually. See "Tax Matters."

The 1940 Act currently limits the number of times the Fund may distribute long-term capital gains in any tax year, which may increase the variability of the Fund's distributions and result in certain distributions being comprised more or less heavily than others of long-term capital gains currently eligible for favorable income tax rates. The Fund, as well as several other PIMCO-managed closed end funds, has received exemptive relief from the SEC permitting it to make a greater number of capital gains distributions to holders of the ARPS than would otherwise be permitted by Section 19(b) of the 1940 Act and Rule 19b-1 under the 1940 Act.

Unless a Common Shareholder elects to receive distributions in cash, all distributions of Common Shareholders whose shares are registered with the plan agent will be automatically reinvested in additional Common Shares of the Fund under the Fund's Dividend Reinvestment Plan. See "Distributions" and "Dividend Reinvestment Plan."

The Investment Manager, at its own expense, has retained UBS Warburg LLC and Merrill Lynch & Co., Merrill Lynch, Pierce, Fenner & Smith Incorporated to serve as shareholder servicing agents for the Fund. State Street Bank and Trust Company serves as custodian of the Fund's assets and also provides certain fund accounting and sub-administrative services to the Investment Manager on behalf of the Fund. American Stock Transfer & Trust Company, LLC serves as the Fund's transfer agent and dividend disbursement agent. See "Shareholder Servicing Agent, Custodian and Transfer Agent."

The Fund's outstanding Common Shares are listed on the NYSE under the trading or "ticker" symbol "PTY," as will be the Common Shares offered in this prospectus, subject to notice of issuance.

Shares of closed-end investment companies frequently trade at prices lower than NAV. Shares of closed-end investment companies have during some periods traded at prices higher than NAV and during other periods traded at prices lower than NAV. The Fund cannot assure you that Common Shares will trade at a price equal to or higher than NAV in the future. NAV will be reduced immediately following an offering by any sales load and/ or commissions and the amount of offering expenses paid or reimbursed by the Fund. See "Use of Proceeds." In addition to NAV, market price may be affected by factors relating to the Fund such as dividend levels and stability (which will in turn be affected by Fund expenses, including the costs of any leverage used by the Fund, levels of interest payments by the Fund's

portfolio holdings, levels of appreciation/depreciation of the Fund's portfolio holdings, regulation affecting the timing and character of Fund distributions and other factors), portfolio credit quality, liquidity, call protection, market supply and demand and similar factors relating to the Fund's portfolio holdings. See "Use of Leverage," "Principal Risks of the Fund," "Description of Shares" and "Repurchase of Common Shares; Conversion to Open-End Fund" in this prospectus, and see "Repurchase of Common Shares; Conversion to Open-End Fund" in the Statement of Additional Information. The Common Shares are designed for long-term investors and should not be treated as trading vehicles.

The following is a summary of the principal risks associated with an investment in Common Shares of the Fund. Investors should also refer to "Principal Risks of the Fund" in this prospectus and "Investment Objective and Policies" in the Statement of Additional Information for a more detailed explanation of these and other risks associated with investing in the Fund.

As with any stock, the price of the Fund's Common Shares will fluctuate with market conditions and other factors. If you sell your Common Shares, the price received may be more or less than your original investment. Net asset value of the Fund's Common Shares will be reduced immediately following an offering by any sales load and/or commissions and offering expenses paid or reimbursed by the Fund in connection with such offering. The completion of an offering may result in an immediate dilution of the NAV per Common Share for all existing Common Shareholders. The Common Shares are designed for long-term investors and should not be treated as trading vehicles. Shares of closed-end management investment companies frequently trade at a discount from their NAV. The Common Shares may trade at a price that is less than the offering price for Common Shares issued pursuant to an offering. This risk may be greater for investors who sell their Common Shares relatively shortly after completion of an offering.

The Fund could lose money if the issuer or guarantor of a debt security (including a security purchased with securities lending collateral), or the counterparty to a derivatives contract, repurchase agreement or a loan of portfolio securities, is unable or unwilling, or is perceived (whether by market participants, rating agencies, pricing services or otherwise) as unable or unwilling, to make timely principal and/or interest payments, or to otherwise honor its obligations. The downgrade of the credit of a security held by the Fund may decrease its value. Securities are subject to varying degrees of credit risk, which are often reflected in credit ratings. Measures such as average credit quality may not accurately reflect the true credit risk of the Fund. This is especially the case if the Fund holds securities with widely varying credit ratings. Therefore, if the Fund has an average credit rating that suggests a certain credit quality, the Fund may in fact be subject to greater credit risk than the average would suggest. This risk is greater to the extent the Fund uses leverage or derivatives in connection with the management of the Fund. Municipal bonds are subject to the risk that litigation, legislation or other political events, local business or economic conditions, or the bankruptcy of the issuer could have a significant effect on an issuer's ability to make payments of principal and/or interest.

The Fund will not normally invest more than 20% of its total assets in debt instruments, other than mortgage-related and other asset-backed securities, that are, at the time of purchase, rated CCC or lower by S&P and Fitch and Caa1 or lower by Moody's, or that are unrated but determined by PIMCO to be of comparable quality. The Fund may invest without limit in mortgage-related and other asset-backed securities regardless of rating. The Fund may invest up to 5% of its total assets in defaulted bonds when PIMCO believes that the issuer's potential revenues and prospects for recovery are favorable, except that the Fund may invest in mortgage-related and other asset-backed securities without regard to this limit, subject to the Fund's other investment policies.

In general, lower rated debt securities carry a greater degree of risk that the issuer will lose its ability to make interest and principal payments, which could have a negative effect on the NAV of the Fund's Common Shares or Common Share dividends. Securities of below investment grade quality are regarded as having predominantly speculative characteristics with respect to capacity to pay interest and repay principal, and are commonly referred to as "high yield" securities or "junk bonds." High yield securities involve a greater risk of default and their prices are generally more volatile and sensitive to actual or perceived negative developments, such as a decline in the issuer's revenues or revenues of underlying borrowers or a general economic downturn, than are the prices of higher grade securities. Debt securities in the lowest investment grade category also may be considered to possess some speculative characteristics by certain rating agencies. The Fund may purchase distressed securities that are in default or the issuers of which are in bankruptcy, which involve heightened risks. See "Principal Risks of the Fund—Distressed and Defaulted Securities Risk." An economic downturn could severely affect the ability of issuers (particularly those that are highly leveraged) to service their debt obligations or to repay their obligations upon maturity. Lower-rated securities are generally less liquid than higher-rated securities, which may have an adverse effect on the Fund's ability to dispose of a particular security. For example, under adverse market or economic conditions, the secondary market for below investment grade securities could contract further, independent of any specific adverse changes in the condition of a particular issuer, and certain securities in the Fund's portfolio may become illiquid or less liquid. As a result, the Fund could find it more difficult to sell these securities or may be able to sell these securities only at prices lower than if such securities were widely traded. See "Principal Risks of the Fund—Liquidity Risk." To the extent the Fund focuses on below investment grade debt obligations, PIMCO's capabilities in analyzing credit quality and associated risks will be particularly important, and there can be no assurance that PIMCO will be successful in this regard. See "Portfolio Contents—High Yield Securities" for additional information. Due to the risks involved in investing in high yield securities, an investment in the Fund should be considered speculative.

characteristics of a particular issue. In determining whether to retain or sell such a security, PIMCO may consider factors including, but not limited to, PIMCO's assessment of the credit quality of the issuer of such security, the price at which such security could be sold and the rating, if any, assigned to such security by other rating agencies. Analysis of creditworthiness may be more complex for issuers of high yield securities than for issuers of higher quality debt securities.

The market price of securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. Securities may decline in value due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of a security may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates, adverse changes to credit markets or adverse investor sentiment generally. The value of a security may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Equity securities generally have greater price volatility than fixed income securities. Credit ratings downgrades may also negatively affect securities held by the Fund. Even when markets perform well, there is no assurance that the investments held by the Fund will increase in value along with the broader market. In addition, market risk includes the risk that geopolitical events will disrupt the economy on a national or global level. For instance, terrorism, market manipulation, government defaults, government shutdowns, political changes or diplomatic developments, and natural/environmental disasters can all negatively impact the securities markets, which could cause the Fund to lose value. Any market disruptions could also prevent the Fund from executing advantageous investment decisions in a timely manner. To the extent the Fund focuses its investments in a region enduring geopolitical market disruption, it will face higher risks of loss. Thus, investors should closely monitor current market conditions to determine whether a specific Fund meets their individual financial needs and tolerance for risk.

Current market conditions may pose heightened risks with respect to funds that invest in fixed income securities. As discussed more under "Interest Rate Risk," interest rates in the U.S. are near historically low levels. However, continued economic recovery, the end of the Federal Reserve Board's quantitative easing program, and an increased likelihood of a rising interest rate environment increase the risk that interest rates will continue to rise in the near future. Any further interest rate increases in the future could cause the value of the Fund to decrease. As such, fixed income securities markets may experience heightened levels of interest rate, volatility and liquidity risk.

Exchanges and securities markets may close early, close late or issue trading halts on specific securities, which may result in, among other things, the Fund being unable to buy or sell certain securities or financial instruments at an advantageous time or accurately price its portfolio investments.

Interest rate risk is the risk that fixed income securities and other instruments in the Fund's portfolio will decline in value because of a change in interest rates. As nominal interest rates rise, the value of certain fixed income securities held by the Fund is likely to decrease. A nominal interest rate can be described as the sum of a real interest rate and an expected inflation rate. Interest rate changes can be sudden and unpredictable, and the Fund may lose money as a result of movements in interest rates. The Fund may not be able to hedge against changes in interest rates or may choose not to do so for cost or other reasons. In addition, any hedges may not work as intended.

A wide variety of factors can cause interest rates to rise (e.g., central bank monetary policies, inflation rates, general economic conditions). This risk may be particularly acute in the current market environment because market interest rates are currently near historically low levels. This, combined with recent economic recovery, the Federal Reserve Board's conclusion of its quantitative easing program, and increases in federal funds interest rates in 2015, 2016 and 2017 which had not occurred since 2006, could potentially increase the probability of an upward interest rate environment in the near future. To the extent the Federal Reserve Board continues to raise interest rates, there is a risk that rates across the financial system may rise.

Fixed income securities with longer durations tend to be more sensitive to changes in interest rates, usually making them more volatile than securities with shorter durations. Duration is a measure used to determine the sensitivity of a security's price to changes in interest rates that incorporates a security's yield, coupon, final maturity and call features, among other characteristics. Duration is useful primarily as a measure of the sensitivity of a fixed income security's market price to interest rate (i.e. yield) movements. All other things remaining equal, for each one percentage point increase in interest rates, the value of a portfolio of fixed income investments would generally be expected to decline by one percent for every year of the portfolio's average duration above zero. For example, the value of a portfolio of fixed income securities with an average duration of eight years would generally be expected to decline by approximately 8% if interest rates rose by one percentage point.

Variable and floating rate securities generally are less sensitive to interest rate changes but may decline in value if their interest rates do not rise as much, or as quickly, as interest rates in general. Conversely, floating rate securities will not generally increase in value if interest rates decline. Inverse floating rate securities may decrease in value if interest rates increase. Inverse floating rate securities may also exhibit greater price volatility than a fixed rate obligation with similar credit quality. When the Fund holds variable or floating rate securities, a decrease (or, in the case of inverse floating rate securities, an increase) in market interest rates will adversely affect the income received from such securities and the NAV of the Fund's shares.

experienced negative interest rates on certain fixed income instruments. Very low or negative interest rates may magnify interest rate risk. Changing interest rates, including rates that fall below zero, may have unpredictable effects on markets, may result in heightened market volatility and may detract from Fund performance to the extent the Fund is exposed to such interest rates.

Measures such as average duration may not accurately reflect the true interest rate sensitivity of the Fund. This is especially the case if the Fund consists of securities with widely varying durations. Therefore, if the Fund has an average duration that suggests a certain level of interest rate risk, the Fund may in fact be subject to greater interest rate risk than the average would suggest. This risk is greater to the extent the Fund uses leverage or derivatives in connection with the management of the Fund.

Convexity is an additional measure used to understand a security's or Fund's interest rate sensitivity. Convexity measures the rate of change of duration in response to changes in interest rates. With respect to a security's price, a larger convexity (positive or negative) may imply more dramatic price changes in response to changing interest rates. Convexity may be positive or negative. Negative convexity implies that interest rate increases result in increased duration, meaning increased sensitivity in prices in response to rising interest rates. Thus, securities with negative convexity, which may include bonds with traditional call features and certain mortgage-backed securities, may experience greater losses in periods of rising interest rates. Accordingly, if the Fund holds such securities, the Fund may be subject to a greater risk of losses in periods of rising interest rates.

Rising interest rates may result in a decline in value of the Fund's fixed income investments and in periods of volatility. Further, while U.S. bond markets have steadily grown over the past three decades, dealer "market making" ability has remained relatively stagnant. As a result, dealer inventories of certain types of bonds and similar instruments, which provide a core indication of the ability of financial intermediaries to "make markets," are at or near historic lows in relation to market size. Because market makers provide stability to a market through their intermediary services, the significant reduction in dealer inventories could potentially lead to decreased liquidity and increased volatility in the fixed income markets. Such issues may be exacerbated during periods of economic uncertainty. All of these factors, collectively and/or individually, could cause the Fund to lose value.

The value of a security may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer's goods or services, as well as the historical and prospective earnings of the issuer and the value of its assets. A change in the financial condition of a single issuer may affect securities markets as a whole. These risks can apply to the Common Shares issued by the Fund and to the issuers of securities and other instruments in which the Fund invests.

The Fund's use of leverage (as described under "Use of Leverage" in the body of this prospectus) creates the opportunity for increased Common Share net income, but also creates special risks for Common Shareholders. To the extent used, there is no assurance that the Fund's leveraging strategies will be successful. Leverage is a speculative technique that may expose the Fund to greater risk and increased costs. The Fund's assets attributable to its outstanding Preferred Shares or the net proceeds the that Fund obtains from its use of reverse repurchase agreements, dollar rolls and/or borrowings, if any, will be invested in accordance with the Fund's investment objective and policies as described in this prospectus. Dividends payable with respect to the Preferred Shares and interest expense payable by the Fund with respect to any reverse repurchase agreements, dollar rolls and borrowings (for dividends payable with respect to Preferred Shares) will generally be based on shorter-term interest rates that would be periodically reset. So long as the Fund's portfolio investments provide a higher rate of return (net of applicable Fund expenses) than the dividend rate on the Preferred Shares and the interest expenses and other costs to the Fund of such other leverage, the investment of the proceeds thereof will generate more income than will be needed to pay the costs of the leverage. If so, and all other things being equal, the excess may be used to pay higher dividends to Common Shareholders than if the Fund were not so leveraged. If, however, shorter-term interest rates rise relative to the rate of return on the Fund's portfolio, the interest and other costs of leverage to the Fund (including interest expenses on reverse repurchase agreements, dollar rolls and borrowings and the dividend rate on any outstanding preferred shares) could exceed the rate of return on the debt obligations and other investments held by the Fund, thereby reducing return to Common Shareholders. In addition, fees and expenses of any form of leverage used by the Fund will be borne entirely by the Common Shareholders (and not by preferred shareholders, if any) and will reduce the investment return of the Common Shares. Therefore, there can be no assurance that the Fund's use of leverage will result in a higher yield on the Common Shares, and it may result in losses. In addition, any Preferred Shares issued by the Fund are expected to pay cumulative dividends, which may tend to increase leverage risk.

Leverage creates several major types of risks for Common Shareholders, including:

the likelihood of greater volatility of NAV and market price of Common Shares, and of the investment return to Common Shareholders, than a comparable portfolio without leverage;

the possibility either that Common Share dividends will fall if the interest and other costs of leverage rise, or that dividends paid on Common Shares will fluctuate because such costs vary over time; and

the effects of leverage in a declining market or a rising interest rate environment, as leverage is likely to cause a greater decline in the NAV of the Common Shares than if the Fund were not leveraged and may result in a greater decline in the market value of the Common Shares.

In addition, holders of ARPS and any other preferred shareholders of the Fund, and the counterparties to the Fund's other leveraging transactions, have or will have priority of payment over the Fund's Common Shareholders.

The use by the Fund of reverse repurchase agreements and dollar rolls to obtain leverage also involves special risks. For instance, the market value of

the securities that the Fund is obligated to repurchase under a reverse repurchase agreement or dollar roll may decline below the repurchase price. See "The Fund's Investment Objective and Policies—Portfolio Contents— Reverse Repurchase Agreements and Dollar Rolls."

In addition to reverse repurchase agreements, dollar rolls and/or borrowings (or a future issuance of preferred shares), the Fund may engage in other transactions that may give rise to a form of leverage including, among others, futures and forward contracts (including foreign currency exchange contracts), credit default swaps, total return swaps, basis swaps and other derivative transactions, loans of portfolio securities, short sales and when-issued, delayed delivery and forward commitment transactions). The Fund's use of such transactions gives rise to associated leverage risks described above, and may adversely affect the Fund's income, distributions and total returns to Common Shareholders. The Fund manages some of its derivative positions by segregating an amount of cash or liquid securities equal to the notional value or the market value, as applicable, of those positions. See "Principal Risks of the Fund—Segregation and Coverage Risk." The Fund may also offset derivatives positions against one another or against other assets to manage effective market exposure resulting from derivatives in its portfolio. To the extent that any offsetting positions do not behave in relation to one another as expected, the Fund may perform as if it is leveraged through use of these derivative strategies. See "Use of Leverage."

The SEC has issued a proposed rule relating to a registered investment company's use of derivatives and related instruments that, if adopted, could potentially require the Fund to reduce its use of leverage and/or observe more stringent asset coverage and related requirements than are currently imposed by the 1940 Act, which could adversely affect the value or performance of the Fund and the Common Shares.

Because the fees received by the Investment Manager are based on the average daily net assets of the Fund (including assets attributable to the ARPS and any other preferred shares that may be outstanding), the Investment Manager has a financial incentive for the Fund to maintain and issue preferred shares, which may create a conflict of interest between the Investment Manager, on the one hand, and the Common Shareholders, on the other hand. The fees received by the Investment Manager are not, however, charged on asset attributable to leverage obtained by the Fund other than through preferred shares.

Although the Fund's ARPS ordinarily would pay dividends at rates set at periodic auctions, the weekly auctions for the ARPS (and auctions for similar preferred shares issued by closed-end funds in the U.S.) have failed since February 2008. The dividend rates on the ARPS since that time have been paid, and the Fund expects that they will continue to be paid for the foreseeable future, at the "maximum applicable rate" under the Fund's Bylaws (i.e., a multiple of a reference rate, which is the applicable "AA" Financial Composite Commercial Paper Rate (for a dividend period of fewer than 184 days) or the applicable Treasury Index Rate (for a dividend period of 184 days or more)). An increase in market interest rates generally, therefore, could increase substantially the dividend rate required to be paid by the Fund to the holders of ARPS, which would increase the costs associated with the Fund's leverage and reduce the Fund's net income available for distribution to Common Shareholders.

In addition, the multiple used to calculate the maximum applicable rate is based in part on the credit rating assigned to the ARPS by the applicable rating agency (currently, Moody's), with the multiple generally increasing as the rating declines. In September 2011, Moody's, a ratings agency that provides ratings for the Fund's ARPS, downgraded its rating of the ARPS from "Aaa" to "A2," citing persistently thin asset coverage levels, increased NAV volatility and concerns about secondary market liquidity for some assets supporting rated obligations. In July 2012, Moody's downgraded its rating of the ARPS from "A2" to "A3" pursuant to a revised ratings methodology adopted by Moody's. Also, in May 2014, Moody's upgraded its rating of the Fund's ARPS from A3 to A2, citing changes in the Fund's asset coverage ratio and economic leverage. Under the Bylaws, the 2011 downgrade resulted in an increase in the multiple used to calculate the maximum applicable rate from 150% to 200%, thereby increasing the dividend rate payable to ARPS holders and increasing the costs to Common Shareholders associated with the Fund's leverage. See "Use of Leverage" and "Description of Capital Structure." The ARPS could be subject to further ratings downgrades in the future, possibly resulting in further increases to the maximum applicable rate.

Therefore, it is possible that a substantial rise in market interest rates and/or further ratings downgrades of the ARPS could, by reducing income available for distribution to the Common Shareholders and otherwise detracting from the Fund's investment performance, make the Fund's continued use of Preferred Shares for leverage purposes less attractive than such use is currently considered to be. In such case, the Fund may elect to redeem some or all of the Preferred Shares outstanding, which may require it to dispose of investments at inopportune times and to incur losses on such dispositions. Such dispositions may adversely affect the Fund's investment performance generally, and the resultant loss of leverage may materially and adversely affect the Fund's investment returns to Common Shareholders. In 2008 and 2009, the Fund was effectively required to redeem a portion of its ARPS due to market dislocations that caused the value of the Fund's portfolio securities and related asset coverage to decline. In order to increase and maintain the Fund's asset coverage above the requisite 200% level, in December 2008 and March and April 2009, the Fund redeemed 1,920 shares ($48,000,000) of each series of its outstanding ARPS, in each case at face value (i.e., a total of 9,600 shares ($240,000,000) across all series).

On January 16, 2015, the Fund commenced a voluntary tender offer for up to 100% of its outstanding ARPS at a price equal to 87% of the ARPS' per share liquidation preference of $25,000. The Fund accepted 3,482 ARPS for payment, representing approximately 27% of its outstanding ARPS, such that on February 27, 2015, the expiration of the tender offer, the Fund had a total of 9,518 ARPS outstanding with a total liquidation value of $237,950,000.

The Fund is also subject to certain asset coverage tests associated with the rating agency that rates the ARPS— currently Moody's. Failure by the Fund to maintain the asset coverages (or to cure such failure in a timely manner) may require the Fund to redeem ARPS. See "Description of Capital Structure." Failure to satisfy ratings agency asset coverage tests or other

guidelines could also result in the applicable ratings agency downgrading its then-current ratings on the ARPS, as described above. Moreover, the rating agency guidelines impose restrictions or limitations on the Fund's use of certain financial instruments or investment techniques that the Fund might otherwise utilize in order to achieve its investment objective, which may adversely affect the Fund's investment performance. Rating agency guidelines may be modified by the rating agencies in the future and, if adopted by the Fund, such modifications may make such guidelines substantially more restrictive, which could further negatively affect the Fund's investment performance.

Liquidity risk exists when particular investments are difficult to purchase or sell at the time that the Fund would like or at the price that the Fund believes such investments are currently worth. Many of the Fund's investments may be illiquid. Illiquid securities may become harder to value, especially in changing markets. The Fund's investments in illiquid securities may reduce the returns of the Fund because it may be unable to sell the illiquid securities at an advantageous time or price or possibly require the Fund to dispose of other investments at unfavorable times or prices in order to satisfy its obligations, which could prevent the Fund from taking advantage of other investment opportunities. Additionally, the market for certain investments may become illiquid under adverse market or economic conditions independent of any specific adverse changes in the conditions of a particular issuer. Bond markets have consistently grown over the past three decades while the capacity for traditional dealer counterparties to engage in fixed income trading has not kept pace and in some cases has decreased. As a result, dealer inventories of corporate bonds, which provide a core indication of the ability of financial intermediaries to "make markets," are at or near historic lows in relation to market size.

Because market makers seek to provide stability to a market through their intermediary services, the significant reduction in dealer inventories could potentially lead to decreased liquidity and increased volatility in the fixed income markets. Such issues may be exacerbated during periods of economic uncertainty. In such cases, the Fund, due to limitations on investments in illiquid securities and the difficulty in purchasing and selling such securities or instruments, may be unable to achieve its desired level of exposure to a certain sector. To the extent that the Fund's principal investment strategies involve securities of companies with smaller market capitalizations, foreign (non-U.S.) securities, Rule 144A securities, senior loans, illiquid sectors of fixed income securities, derivatives or securities with substantial market and/or credit risk, the Fund will tend to have the greatest exposure to liquidity risk. Further, fixed income securities with longer durations until maturity face heightened levels of liquidity risk as compared to fixed income securities with shorter durations until maturity. It may also be the case that other market participants may be attempting to liquidate fixed income holdings at the same time as the Fund, causing increased supply in the market and contributing to liquidity risk and downward pricing pressure. See "Principal Risks of the Fund— Valuation Risk."

The Fund's investment performance depends upon how its assets are allocated and reallocated. A principal risk of investing in the Fund is that PIMCO may make less than optimal or poor asset allocation decisions. PIMCO employs an active approach to allocation among multiple fixed income sectors, but there is no guarantee that such allocation techniques will produce the desired results. It is possible that PIMCO will focus on an investment that performs poorly or underperforms other investments under various market conditions. You could lose money on your investment in the Fund as a result of these allocation decisions.

The Fund is subject to management risk because it is an actively managed investment portfolio. PIMCO and each individual portfolio manager will apply investment techniques and risk analysis in making investment decisions for the Fund, but there can be no guarantee that these decisions will produce the desired results. Certain securities or other instruments in which the Fund seeks to invest may not be available in the quantities desired. In addition, regulatory restrictions, actual or potential conflicts of interest or other considerations may cause PIMCO to restrict or prohibit participation in certain investments. In such circumstances, PIMCO or the individual portfolio managers may determine to purchase other securities or instruments as substitutes. Such substitute securities or instruments may not perform as intended, which could result in losses to the Fund. To the extent the Fund employs strategies targeting perceived pricing inefficiencies, arbitrage strategies or similar strategies, it is subject to the risk that the pricing or valuation of the securities and instruments involved in such strategies may change unexpectedly, which may result in reduced returns or losses to the Fund. Additionally, legislative, regulatory, or tax restrictions, policies or developments may affect the investment techniques available to PIMCO and each individual portfolio manager in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. There also can be no assurance that all of the personnel of PIMCO will continue to be associated with PIMCO for any length of time. The loss of the services of one or more key employees of PIMCO could have an adverse impact on the Fund's ability to realize its investment objective.

In addition, the Fund may rely on various third-party sources to calculate its net asset value. As a result, the Fund is subject to certain operational risks associated with reliance on service providers and service providers' data sources. In particular, errors or systems failures and other technological issues may adversely impact the Fund's calculations of its net asset value, and such net asset value calculation issues may result in inaccurately calculated net asset values, delays in net asset value calculation and/or the inability to calculate net asset values over extended periods. The Fund may be unable to recover any losses associated with such failures.

Call risk refers to the possibility 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 in which the Fund has invested, 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.

The Fund may invest in foreign (non-U.S.) securities and may experience more rapid and extreme changes in value than the Fund that invests exclusively in securities of U.S. companies. The securities markets of many foreign countries are relatively small, with a limited number of companies representing a small number of industries. Additionally, issuers of foreign (non-U.S.) securities are usually not subject to the same degree of regulation as U.S. issuers. Reporting, accounting, auditing and custody standards of foreign countries differ, in some cases significantly, from U.S. standards. Global economies and financial markets are becoming increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. Also, nationalization, expropriation or confiscatory taxation, currency blockage, political changes or diplomatic developments could adversely affect the Fund's investments in a foreign country. In the event of nationalization, expropriation or other confiscation, the Fund could lose its entire investment in foreign (non-U.S.) securities. Adverse conditions in a certain region can adversely affect securities of other countries whose economies appear to be unrelated. To the extent that the Fund invests a significant portion of its assets in a specific geographic region, the Fund will generally have more exposure to regional economic risks associated with foreign (non-U.S.) investments. Foreign (non-U.S.) securities may also be less liquid and more difficult to value than securities of U.S. issuers.

The global economic crisis brought several small economies in Europe to the brink of bankruptcy and many other economies into recession and weakened the banking and financial sectors of many European countries. For example, the governments of Greece, Spain, Portugal, and the Republic of Ireland have all experienced large public budget deficits, the effects of which are still yet unknown and may slow the overall recovery of the European economies from the global economic crisis. In addition, due to large public deficits, some European countries may be dependent on assistance from other European governments and institutions or other central banks or supranational agencies such as the International Monetary Fund. Assistance may be dependent on a country's implementation of reforms or reaching a certain level of performance. Failure to reach those objectives or an insufficient level of assistance could result in a deep economic downturn which could significantly affect the value of the Fund's European investments. It is possible that one or more Economic and Monetary Union member countries could abandon the euro and return to a national currency and/or that the euro will cease to exist as a single currency in its current form. The exit of any country out of the euro may have an extremely destabilizing effect on other eurozone countries and their economies and a negative effect on the global economy as a whole. Such an exit by one country may also increase the possibility that additional countries may exit the euro should they face similar financial difficulties.

At a referendum in June 2016, the United Kingdom (the UK) voted to leave the European Union ("EU"). In connection with the British exit from the EU (commonly known as "Brexit"), it is expected that the UK will invoke article 50 of the Treaty of Lisbon to withdraw from the EU in due course, however there is a significant degree of uncertainty about how negotiations relating to the UK's withdrawal and new trade agreements will be conducted, as well as the potential consequences and precise timeframe for Brexit. It is expected that the UK's exit from the EU will take place within two years of the UK notifying the European Council that it intends to withdraw from the EU. During this period and beyond, the impact of any partial or complete dissolution of the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility and illiquidity, and potentially lower economic growth in markets in the UK, Europe and globally, which may adversely affect the value of the Fund's portfolio investments.

The UK has one of the largest economies in Europe, and member countries of the EU are substantial trading partners of the UK. The City of London's economy is dominated by financial services, some of which may have to move outside of the UK post-referendum (e.g., currency trading, international settlement). Under the referendum, banks may be forced to move staff and comply with two separate sets of rules or lose business to banks in Europe. Furthermore, the referendum creates the potential for decreased trade, the possibility of capital outflows, devaluation of the pound sterling, the cost of higher corporate bond spreads due to uncertainty, and the risk that all the above could damage business and consumer spending as well as foreign direct investment. As a result of the referendum, the British economy and its currency may be negatively impacted by changes to its economic and political relations with the EU. Any further exits from the EU, or the possibility of such exits, would likely cause additional market disruption globally and introduce new legal and regulatory uncertainties.

The impact of the referendum in the near- and long-term is still unknown and could have additional adverse effects on economies, financial markets, currencies and asset valuations around the world. Any attempt by the Fund to hedge against or otherwise protect its portfolio or to profit from such circumstances may fail and, accordingly, an investment in the Fund could lose money over short or long periods.

The Fund may invest in securities and instruments that are economically tied to Russia. Investments in Russia are subject to various risks such as political, economic, legal, market and currency risks. The risks include uncertain political and economic policies, short term market volatility, poor accounting standards, corruption and crime, an inadequate regulatory system, and unpredictable taxation. Investments in Russia are particularly subject to the risk that economic sanctions may be imposed by the United States and/or other countries. Such sanctions — which may impact companies in many sectors, including energy, financial services and defense, among others — may negatively impact the Fund's performance and/or ability to achieve its investment objective. The Russian securities market is characterized by limited volume of trading, resulting in difficulty in obtaining accurate prices. The Russian securities market, as compared to U.S. markets, has significant price volatility, less liquidity, a smaller market capitalization and a smaller number of traded securities. There may be little publicly available information about issuers. Settlement, clearing and registration of securities transactions are subject to risks because of registration systems

that may not be subject to effective government supervision. This may result in significant delays or problems in registering the transfer of securities. Russian securities laws may not recognize foreign nominee accounts held with a custodian bank, and therefore the custodian may be considered the ultimate owner of securities they hold for their clients. Ownership of securities issued by Russian companies is recorded by companies themselves and by registrars instead of through a central registration system. It is possible that the ownership rights of the Fund could be lost through fraud or negligence. While applicable Russian regulations impose liability on registrars for losses resulting from their errors, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities in the event of loss of share registration. Adverse currency exchange rates are a risk and there may be a lack of available currency hedging instruments. Investments in Russia may be subject to the risk of nationalization or expropriation of assets. Oil, natural gas, metals, and timber account for a significant portion of Russia's exports, leaving the country vulnerable to swings in world prices.

Foreign investment risk may be particularly high to the extent that the Fund invests in securities of issuers based in or doing business in emerging market countries or invests in securities denominated in the currencies of emerging market countries. Investing in securities of issuers based in or doing business in emerging markets entails all of the risks of investing in foreign securities noted above, but to a heightened degree.

Investments in emerging market countries pose a greater degree of systemic risk (i.e., the risk of a cascading collapse of multiple institutions within a country, and even multiple national economies). The inter-relatedness of economic and financial institutions within and among emerging market economies has deepened over the years, with the effect that institutional failures and/or economic difficulties that are of initially limited scope may spread throughout a country, a region or even among all or most emerging market countries.

This may undermine any attempt by the Fund to reduce risk through geographic diversification of its portfolio investments among emerging market countries. There is a heightened possibility of imposition of withholding taxes on interest or dividend income generated from emerging market securities. Governments of emerging market countries may engage in confiscatory taxation or expropriation of income and/or assets to raise revenues or to pursue a domestic political agenda. In the past, emerging market countries have nationalized assets, companies and even entire sectors, including the assets of foreign investors, with inadequate or no compensation to the prior owners. There can be no assurance that the Fund will not suffer a loss of any or all of its investments or, interest or dividends thereon, due to adverse fiscal or other policy changes in emerging market countries.

There is also a greater risk that an emerging market government may take action that impedes or prevents the Fund from taking income and/or capital gains earned in the local currency and converting into U.S. dollars (i.e., "repatriating" local currency investments or profits). Certain emerging market countries have sought to maintain foreign exchange reserves and/or address the economic volatility and dislocations caused by the large international capital flows by controlling or restricting the conversion of the local currency into other currencies. This risk tends to become more acute when economic conditions otherwise worsen. There can be no assurance that if the Fund earns income or capital gains in an emerging market currency or PIMCO otherwise seeks to withdraw the Fund's investments from a given emerging market country, capital controls imposed by such country will not prevent, or cause significant expense in, doing so.

Bankruptcy law and creditor reorganization processes may differ substantially from those in the United States, resulting in greater uncertainty as to the rights of creditors, the enforceability of such rights, reorganization timing and the classification, seniority and treatment of claims. In certain emerging market countries, although bankruptcy laws have been enacted, the process for reorganization remains highly uncertain. In addition, it may be impossible to seek legal redress against an issuer that is a sovereign state.

Other heightened risks associated with emerging markets investments include without limitation: (i) risks due to less social, political and economic stability; (ii) the smaller size of the market for such securities and a lower volume of trading, resulting in a lack of liquidity and in price volatility; (iii) certain national policies which may restrict the Fund's investment opportunities, including restrictions on investing in issuers or industries deemed sensitive to relevant national interests and requirements that government approval be obtained prior to investment by foreign persons; (iv) certain national policies that may restrict the Fund's repatriation of investment income, capital or the proceeds of sales of securities, including temporary restrictions on foreign capital remittances; (v) the lack of uniform accounting and auditing standards and/or standards that may be significantly different from the standards required in the United States; (vi) less publicly available financial and other information regarding issuers; (vii) potential difficulties in enforcing contractual obligations; and (viii) higher rates of inflation, higher interest rates and other economic concerns. The Fund may invest to a substantial extent in emerging market securities that are denominated in local currencies, subjecting the Fund to a greater degree of foreign currency risk. See "Principal Risks of the Fund—Currency Risk." Also, investing in emerging market countries may entail purchases of securities of issuers that are insolvent, bankrupt or otherwise of questionable ability to satisfy their payment obligations as they become due, subjecting the Fund to a greater amount of credit risk and/or high yield risk.

The Fund may, but is not required to, utilize a variety of derivative instruments (both long and short positions) for investment or risk management purposes, as well as to leverage its portfolio. The Fund may use derivatives to gain exposure to securities markets in which it may invest (e.g., pending investment of the proceeds of this offering in individual securities, as well as on an ongoing basis). The Fund may also use derivatives to add leverage to its portfolio. See "Principal Risks of the Fund —Leverage Risk." Derivatives transactions that the Fund may utilize include, but are not limited to, purchases or sales of futures and forward contracts (including foreign currency exchange contracts), call and put options, credit default swaps, total return swaps, basis swaps and other

swap agreements. The Fund may also have exposure to derivatives, such as interest rate or credit default swaps, through investment in credit-linked trust certificates and other securities issued by special purpose or structured vehicles. The Fund's use of derivative instruments involves risks different from, and possibly greater than, the risks associated with investing directly in securities and other traditional investments. Derivatives are subject to a number of risks described elsewhere in this prospectus, such as liquidity risk, interest rate risk, issuer risk, credit risk, leveraging risk, counterparty risk, and management risk. See "Principal Risks of the Fund —Segregation and Coverage Risk." They also involve the risk of mispricing or improper valuation, the risk of unfavorable or ambiguous documentation and the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. If the Fund invests in a derivative instrument, it could lose more than the principal amount invested. Also, suitable derivative transactions may not be available in all circumstances and there can be no assurance that the Fund will engage in these transactions to reduce exposure to other risks when that would be beneficial. The Fund's use of derivatives also may affect the amount, timing, or character of distributions to, and taxes payable by, Common Shareholders. See "Tax Matters." 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. For derivatives traded on an exchange or through a central counterparty, credit risk resides with the creditworthiness of the Fund's clearing broker, or the clearinghouse itself, rather than to a counterparty in an OTC derivative transaction.

The regulation of the derivatives markets has increased over the past several years, and additional future regulation of the derivatives markets may make derivatives more costly, may limit the availability or reduce the liquidity of derivatives, or may otherwise adversely affect the value or performance of derivatives. Any such adverse future developments could impair the effectiveness of the Fund's derivative transactions and cause the Fund to lose value. For instance, in December 2015, the SEC proposed new regulations applicable to a registered investment company's use of derivatives and related instruments. If adopted as proposed, these regulations could significantly limit or impact the Fund's ability to invest in derivatives and other instruments, limit the Fund's ability to employ certain strategies that use derivatives and/or adversely affect the Fund's performance, efficiency in implementing their strategy, liquidity and/or ability to pursue its investment objective.

Credit default swap agreements may involve greater risks than if the Fund had invested in the reference obligation directly since, in addition to general market risks, credit default swaps are subject to illiquidity risk, counterparty risk and credit risk. A buyer generally also will lose its investment and recover nothing should no credit event occur and the swap is held to its termination date. If a credit event were to occur, the value of any deliverable obligation received by the seller (if any), coupled with the upfront or periodic payments previously received, may be less than the full notional value it pays to the buyer, resulting in a loss of value to the seller. When the Fund acts as a seller of a credit default swap, it is exposed to many of the same risks of leverage described herein since if an event of default occurs, the seller must pay the buyer the full notional value of the reference obligation. See "Principal Risks of the Fund—Leverage Risk."

Although the Fund may seek to realize gains by selling credit default swaps that increase in value, to realize gains on selling credit default swaps, an active secondary market for such instruments must exist or the Fund must otherwise be able to close out these transactions at advantageous times. In addition to the risk of losses described above, if no such secondary market exists or the Fund is otherwise unable to close out these transactions at advantageous times, selling credit default swaps may not be profitable for the Fund.

The market for credit default swaps has become more volatile in recent years as the creditworthiness of certain counterparties has been questioned and/or downgraded. The Fund will be subject to credit risk with respect to the counterparties to the credit default swap contract (whether a clearing corporation in the case of a cleared credit default swap or another third party in the case of an uncleared credit default swap). If a counterparty's credit becomes significantly impaired, multiple requests for collateral posting in a short period of time could increase the risk that the Fund may not receive adequate collateral. The Fund may exit its obligations under a credit default swap only by terminating the contract and paying applicable breakage fees, or by entering into an offsetting credit default swap position, which may cause the Fund to incur more losses.

The Fund will be subject to credit risk with respect to the counterparties to the derivative contracts and other instruments entered into by the Fund or held by special purpose or structured vehicles in which the Fund invests. In the event that the Fund enters into a derivative transaction with a counterparty that subsequently becomes insolvent or becomes the subject of a bankruptcy case, the derivative transaction may be terminated in accordance with its terms and the Fund's ability to realize its rights under the derivative instrument and its ability to distribute the proceeds could be adversely affected. If a counterparty becomes bankrupt or otherwise fails to perform its obligations under a derivative contract due to financial difficulties, the Fund may experience significant delays in obtaining any recovery (including recovery of any collateral it has provided to the counterparty) in a dissolution, assignment for the benefit of creditors, liquidation, winding-up, bankruptcy, or other analogous proceeding. In addition, in the event of the insolvency of a counterparty to a derivative transaction, the derivative transaction would typically be terminated at its fair market value. If the Fund is owed this fair market value in the termination of the derivative transaction and its claim is unsecured, the Fund will be treated as a general creditor of such counterparty, and will not have any claim with respect to any underlying security or asset. The Fund may obtain only a limited recovery or may obtain no recovery in such circumstances.

The Fund may invest in a variety of mortgage-related and other asset-backed securities issued by government agencies or other governmental entities or by private originators or issuers.

The mortgage-related securities in which the Fund may invest include, without limit, mortgage pass-through securities, collateralized mortgage obligations ("CMOs"), commercial or residential mortgage-backed securities, mortgage dollar rolls, CMO residuals, stripped mortgage-backed securities ("SMBSs") and other securities that directly or indirectly represent a participation in, or are secured by and payable from, mortgage loans on real property. The Fund may also invest in other types of asset-backed securities, including collateralized debt obligations ("CDOs"), which include collateralized bond obligations ("CBOs"), collateralized loan obligations ("CLOs") and other similarly structured securities.

See "Portfolio Contents—Mortgage-Related And Other Asset-Backed Securities" in this prospectus and "Investment Objective and Policies—Mortgage-Related and Other Asset-Backed Securities" in the Statement of Additional Information for a description of the various mortgage-related and other asset-backed securities in which the Fund may invest and their related risks.

Mortgage-related and other asset-backed securities represent interests in "pools" of mortgages or other assets such as consumer loans or receivables held in trust and often involve risks that are different from or possibly more acute than risks associated with other types of debt instruments. Generally, rising interest rates tend to extend the duration of fixed rate mortgage-related securities, making them more sensitive to changes in interest rates. As a result, in a period of rising interest rates, the Fund may exhibit additional volatility since individual mortgage holders are less likely to exercise prepayment options, thereby putting additional downward pressure on the value of these securities and potentially causing the Fund to lose money. This is known as extension risk. Mortgage-backed securities can be highly sensitive to rising interest rates, such that even small movements can cause the Fund to lose value. Mortgage-backed securities, and in particular those not backed by a government guarantee, are subject to credit risk. When interest rates decline, borrowers may pay off their mortgages sooner than expected. This can reduce the returns of the Fund because the Fund may have to reinvest that money at the lower prevailing interest rates. The Fund's investments in other asset-backed securities are subject to risks similar to those associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets. Payment of principal and interest on asset-backed securities may be largely dependent upon the cash flows generated by the assets backing the securities, and asset-backed securities may not have the benefit of any security interest in the related assets. See "Principal Risks of the Fund— Mortgage Market/Subprime Risk."

The Fund may also invest in the residual or equity tranches of mortgage-related and other asset-backed securities, which may be referred to as subordinate mortgage-backed or asset-backed securities and interest-only mortgage-backed or asset-backed securities. Subordinate mortgage-backed or asset-backed securities are paid interest only to the extent that there are funds available to make payments. To the extent the collateral pool includes a large percentage of delinquent loans, there is a risk that interest payment on subordinate mortgage-backed or asset-backed securities will not be fully paid. There are multiple tranches of mortgage-backed and asset-backed securities, offering investors various maturity and credit risk characteristics. Tranches are categorized as senior, mezzanine, and subordinated/equity or "first loss," according to their degree of risk. The most senior tranche of a mortgage-backed or asset-backed security has the greatest collateralization and pays the lowest interest rate. If there are defaults or the collateral otherwise underperforms, scheduled payments to senior tranches take precedence over those of mezzanine tranches, and scheduled payments to mezzanine tranches take precedence over those to subordinated/equity tranches. Lower tranches represent lower degrees of credit quality and pay higher interest rates intended to compensate for the attendant risks. The return on the lower tranches is especially sensitive to the rate of defaults in the collateral pool. The lowest tranche (i.e., the "equity" or "residual" tranche) specifically receives the residual interest payments (i.e., money that is left over after the higher tranches have been paid and expenses of the issuing entities have been paid) rather than a fixed interest rate. The Fund expects that investments in subordinate mortgage-backed and other asset-backed securities will be subject to risks arising from delinquencies and foreclosures, thereby exposing its investment portfolio to potential losses. Subordinate securities of mortgage-backed and other asset-backed securities are also subject to greater credit risk than those mortgage-backed or other asset-backed securities that are more highly rated.

In addition to credit risk (see "Principal Risks of the Fund—Credit Risk") and possibly high yield risk (see "Principal Risks of the Fund—High Yield Securities Risk"), investment in preferred securities involves certain other risks. Certain preferred securities contain provisions that allow an issuer under certain conditions to skip or defer distributions. If the Fund owns a preferred security that is deferring its distribution, the Fund may be required to include the amount of the deferred distribution in its taxable income for tax purposes although it does not currently receive such amount in cash. In order to receive the special treatment accorded to RICs and their shareholders under the Internal Revenue Code of 1986, as amended (the "Code"), and to avoid U.S. federal income and/or excise taxes at the Fund level, the Fund may be required to distribute this income to shareholders in the tax year in which the income is recognized (without a corresponding receipt of cash). Therefore, the Fund may be required to pay out as an income distribution in any such tax year an amount greater than the total amount of cash income the Fund actually received, and to sell portfolio securities, including at potentially disadvantageous times or prices, to obtain cash needed for these income distributions. Preferred securities often are subject to legal provisions that allow for redemption in the event of certain tax or legal changes or at the issuer's call. In the event of redemption, the Fund may not be able to reinvest the proceeds at comparable rates of return. Preferred securities are subordinated to bonds and other debt securities in an issuer's capital structure in terms of priority for corporate income and liquidation payments, and therefore will be subject to greater credit risk than those debt securities. Preferred securities may trade less frequently and in a more limited volume and may be subject to more abrupt or erratic price movements than many other securities, such as common stocks, corporate debt securities and U.S. Government securities.

Inflation-indexed debt securities are subject to the effects of changes in market interest rates caused by factors other than inflation (real interest

rates). In general, the value of an inflation-indexed security, including TIPS, tends to decrease when real interest rates increase and can increase when real interest rates decrease. Thus generally, during periods of rising inflation, the value of inflation-indexed securities will tend to increase and during periods of deflation, their value will tend to decrease. Interest payments on inflation-indexed securities are unpredictable and will fluctuate as the principal and interest are adjusted for inflation. There can be no assurance that the inflation index used (i.e., the CPI) will accurately measure the real rate of inflation in the prices of goods and services. Increases in the principal value of TIPS due to inflation are considered taxable ordinary income for the amount of the increase in the calendar year. Any increase in the principal amount of an inflation-indexed debt security will be considered taxable ordinary income, even though the Fund will not receive the principal until maturity. Additionally, a CPI swap can potentially lose value if the realized rate of inflation over the life of the swap is less than the fixed market implied inflation rate (fixed breakeven rate) that the investor agrees to pay at the initiation of the swap. With municipal inflation-indexed securities, the inflation adjustment is integrated into the coupon payment, which is federally tax exempt (and may be state tax exempt). For municipal inflation-indexed securities, there is no adjustment to the principal value. Because municipal inflation-indexed securities are a small component of the municipal bond market, they may be less liquid than conventional municipal bonds.

Because it may invest in below-investment grade senior debt, the Fund may be subject to greater levels of credit risk than funds that do not invest in such debt. The Fund may also be subject to greater levels of liquidity risk than funds that do not invest in senior debt. Restrictions on transfers in loan agreements, a lack of publicly available information and other factors may, in certain instances, make senior debt more difficult to sell at an advantageous time or price than other types of securities or instruments. Additionally, if the issuer of senior debt prepays, the Fund will have to consider reinvesting the proceeds in other senior debt or similar instruments that may pay lower interest rates.

Loan interests may take the form of direct interests acquired during a primary distribution and may also take the form of assignments of, novations of or participations in a loan acquired in secondary markets. In addition to credit risk and interest rate risk, the Fund's exposure to loan interests may be subject to additional risks. For example, purchasers of loans and other forms of direct indebtedness depend primarily upon the creditworthiness of the corporate borrower for payment of principal and interest. If the Fund does not receive scheduled interest or principal payments on such indebtedness, the Fund's share price and yield could be adversely affected. Loans that are fully secured offer the Fund more protection than an unsecured loan in the event of non-payment of scheduled interest or principal. However, there is no assurance that the liquidation of collateral from a secured loan would satisfy the corporate borrower's obligation, or that the collateral can be liquidated.

Investments in loans through a purchase of a loan or a direct assignment of a financial institution's interests with respect to a loan may involve additional risks to the Fund. For example, if a loan is foreclosed, the Fund could become owner, in whole or in part, of any collateral, which could include, among other assets, real or personal property, and would bear the costs and liabilities associated with owning and disposing of the collateral. In addition, it is conceivable that under emerging legal theories of lender liability, the Fund could be held liable as co-lender. It is unclear whether loans and other forms of direct indebtedness offer securities law protections against fraud and misrepresentation. In the absence of definitive regulatory guidance, the Fund will rely on PIMCO's research in an attempt to avoid situations where fraud or misrepresentation could adversely affect the Fund. The purchaser of an assignment typically succeeds to all the rights and obligations under the loan agreement with the same rights and obligations as the assigning lender. Assignments may, however, be arranged through private negotiations between potential assignees and potential assignors, and the rights and obligations acquired by the purchaser of an assignment may differ from, and be more limited than, those held by the assigning lender.

In connection with purchasing loan participations, the Fund generally will have no right to enforce compliance by the borrower with the terms of the loan agreement relating to the loan, nor any rights of set-off against the borrower, and the Fund may not directly benefit from any collateral supporting the loan in which it has purchased the loan participation. As a result, the Fund may be subject to the credit risk of both the borrower and the lender that is selling the participation. In the event of the insolvency of the lender selling a participation, the Fund may be treated as a general creditor of the lender and may not benefit from any set-off between the lender and the borrower. Certain loan participations may be structured in a manner designed to prevent purchasers of participations from being subject to the credit risk of the lender with respect to the participation, but even under such a structure, in the event of the lender's insolvency, the lender's servicing of the participation may be delayed and the assignability of the participation impaired.

The Fund may have difficulty disposing of loans and loan participations because to do so it will have to assign or sell such securities to a third party. Because there is no liquid market for many such securities, the Fund anticipates that such securities could be sold only to a limited number of institutional investors. The lack of a liquid secondary market may have an adverse impact on the value of such securities and the Fund's ability to dispose of particular loans and loan participations when that would be desirable, including in response to a specific economic event such as a deterioration in the creditworthiness of the borrower. The lack of a liquid secondary market for loans and loan participations also may make it more difficult for the Fund to assign a value to these securities for purposes of valuing the Fund's portfolio.

To the extent the Fund invests in loans, including bank loans, the Fund may be subject to greater levels of credit risk, call risk, settlement risk and liquidity risk than funds that do not invest in such securities. These instruments are considered predominantly speculative with respect to an issuer's continuing ability to make principal and interest payments and may be more volatile than other types of securities. The Fund may also be subject

to greater levels of liquidity risk than funds that do not invest in loans. In addition, the loans in which the Fund invests may not be listed on any exchange and a secondary market for such loans may be comparatively illiquid relative to markets for other more liquid fixed income securities. Consequently, transactions in loans may involve greater costs than transactions in more actively traded securities. Restrictions on transfers in loan agreements, a lack of publicly-available information, irregular trading activity and wide bid/ask spreads among other factors, may, in certain circumstances, make loans more difficult to sell at an advantageous time or price than other types of securities or instruments. These factors may result in the Fund being unable to realize full value for the loans and/or may result in the Fund not receiving the proceeds from a sale of a senior loan for an extended period after such sale, each of which could result in losses to the Fund. Some loans may have extended trade settlement periods, including settlement periods of greater than 7 days, which may result in cash not being immediately available to the Fund. If an issuer of a senior loan prepays or redeems the loan prior to maturity, the Fund will have to reinvest the proceeds in other loans or similar instruments that may pay lower interest rates. Because of the risks involved in investing in loans, an investment in the Fund should be considered speculative.

The Fund's investments in subordinated and unsecured loans generally are subject to similar risks as those associated with investments in secured loans. Subordinated or unsecured loans are lower in priority of payment to secured loans and are subject to the additional risk that the cash flow of the borrower and property securing the loan or debt, if any, may be insufficient to meet scheduled payments after giving effect to the senior secured obligations of the borrower. This risk is generally higher for subordinated unsecured loans or debt, which are not backed by a security interest in any specific collateral. Subordinated and unsecured loans generally have greater price volatility than secured loans and may be less liquid. There is also a possibility that originators will not be able to sell participations in subordinated or unsecured loans, which would create greater credit risk exposure for the holders of such loans. Subordinate and unsecured loans share the same risks as other below investment grade securities.

There may be less readily available information about most loans and the underlying borrowers than is the case for many other types of securities, including securities issued in transactions registered under the 1933 Act, or registered under the Securities Exchange Act of 1934 (the "Exchange Act"), and borrowers subject to the periodic reporting requirements of Section 13 of the Exchange Act. Loans may be issued by companies that are not subject to SEC reporting requirements and therefore may not be required to file reports with the SEC or may file reports that are not required to comply with SEC form requirements. In addition, such companies may be subject to a less stringent liability disclosure regime than companies subject to SEC reporting requirements. Loans may not be considered "securities," and purchasers, such as the Fund, therefore may not be entitled to rely on the anti-fraud protections of the federal securities laws. Because there is limited public information available regarding loan investments, the Fund is particularly dependent on the analytical abilities of the Fund's portfolio managers.

Economic exposure to loan interests through the use of derivative transactions may involve greater risks than if the Fund had invested in the loan interest directly during a primary distribution or through assignments of, novations of or participations in a loan acquired in secondary markets since, in addition to the risks described above, certain derivative transactions may be subject to leverage risk and greater illiquidity risk, counterparty risk, valuation risk and other risks. See "Principal Risks of the Fund—Derivatives Risk."

Income from the Fund's portfolio will decline if and when the Fund invests the proceeds from matured, traded or called debt obligations at market interest rates that are below the portfolio's current earnings rate. For instance, during periods of declining interest rates, an issuer of debt obligations may exercise an option to redeem securities prior to maturity, forcing the Fund to invest in lower-yielding securities. The Fund also may choose to sell higher yielding portfolio securities and to purchase lower yielding securities to achieve greater portfolio diversification, because the portfolio managers believe the current holdings are overvalued or for other investment-related reasons. A decline in income received by the Fund from its investments is likely to have a negative effect on dividend levels and the market price, NAV and/or overall return of the Common Shares.

The Fund has elected to be treated as a "regulated investment company" under the Code and intends each year to qualify and be eligible to be treated as such, so that it generally will not be subject to U.S. federal income tax on its net investment income or net short-term or long-term capital gains, that it timely distributes (or is deemed to have distributed, as described below) to shareholders. In order to qualify for such treatment, the Fund must meet certain asset diversification tests and at least 90% of its gross income for such year must consist of certain types of qualifying income. Foreign currency gains will generally be treated as qualifying income for purposes of the 90% gross income requirement. However, the U.S. Treasury Department has authority to issue regulations in the future that could treat some or all of the Fund's foreign currency gains as non-qualifying income, thereby jeopardizing the Fund's status as a regulated investment company for all years to which the regulations are applicable. Income derived from some commodity-linked derivatives is not qualifying income, and the treatment of income from some other commodity-linked derivatives is uncertain, for purposes of the 90% gross income test. If for any taxable year the Fund were to fail to meet the income or diversification test described above, the Fund could in some cases cure such failure, including by paying a fund-level tax and, in the case of a diversification test failure, disposing of certain assets.

If, in any year, the Fund were to fail to qualify for treatment as a regulated investment company under the Code, and were ineligible to or did not otherwise cure such failure, the Fund would be subject to tax on its taxable income at corporate rates and, when such income is distributed, shareholders would be subject to a further tax to the extent of the Fund's current or accumulated earnings and profits.

Certain portfolio management techniques, such as, among other things, using reverse repurchase agreements or dollar rolls, purchasing securities on a when-issued or delayed delivery basis, entering into swap agreements, futures contracts or other derivative transactions, or engaging in short sales, may be considered senior securities unless steps are taken to segregate the Fund's assets or otherwise cover its obligations. To avoid having these instruments considered senior securities, the Fund may segregate liquid assets with a value equal (on a daily mark-to-market basis) to its obligations under these types of leveraged transactions, enter into offsetting transactions or otherwise cover such transactions. See "Use of Leverage" in this prospectus. The Fund may be unable to use such segregated assets for certain other purposes, which could result in the Fund earning a lower return on its portfolio than it might otherwise earn if it did not have to segregate those assets in respect of, or otherwise cover, such portfolio positions. To the extent the Fund's assets are segregated or committed as cover, it could limit the Fund's investment flexibility. Segregating assets and covering positions will not limit or offset losses on related positions.

In addition, the Fund is required to satisfy various asset coverage requirements with respect to its ARPS under the terms of the Bylaws. See "Description of Capital Structure-- Rating Agency Guidelines and Asset Coverage" for additional detail.

Convertible securities are fixed income securities, preferred securities or other securities that are convertible into or exercisable for common stock of the issuer (or cash or securities of equivalent value) at either a stated price or a stated rate. The market values of convertible securities may decline as interest rates increase and, conversely, may increase as interest rates decline. A convertible security's market value, however, tends to reflect the market price of the common stock of the issuing company when that stock price approaches or is greater than the convertible security's "conversion price." The conversion price is defined as the predetermined price at which the convertible security could be exchanged for the associated stock. As the market price of the underlying common stock declines, the price of the convertible security tends to be influenced more by the yield of the convertible security. Thus, it may not decline in price to the same extent as the underlying common stock. In the event of a liquidation of the issuing company, holders of convertible securities may be paid before the company's common stockholders but after holders of any senior debt obligations of the company. Consequently, the issuer's convertible securities generally entail less risk than its common stock but more risk than its debt obligations. Convertible securities are often rated below investment grade or not rated because they fall below debt obligations and just above common equity in order of preference or priority on the issuer's balance sheet. See "Principal Risks of the Fund—High Yield Securities Risk."

The Fund may invest in synthetic convertible securities, which are created through a combination of separate securities that possess the two principal characteristics of a traditional convertible security, i.e., an income-producing security ("income-producing component") and the right to acquire an equity security ("convertible component"). The income-producing component is achieved by investing in non-convertible, income-producing securities such as bonds, preferred securities and money market instruments. The convertible component is achieved by purchasing warrants or options to buy common stock at a certain exercise price, or options on a stock index. The values of synthetic convertible securities will respond differently to market fluctuations than a traditional convertible security because a synthetic convertible is composed of two or more separate securities or instruments, each with its own market value. Synthetic convertible securities are also subject to the risks associated with derivatives. See "Principal Risks of the Fund—Derivatives Risk." In addition, if the value of the underlying common stock or the level of the index involved in the convertible element falls below the strike price of the warrant or option, the warrant or option may lose all value.

The risks of investing in contingent convertible securities ("CoCos") include, without limitation, the risk that interest payments will be cancelled by the issuer or a regulatory authority, the risk of ranking junior to other creditors in the event of a liquidation or other bankruptcy-related event as a result of holding subordinated debt, the risk of the Fund's investment becoming further subordinated as a result of conversion from debt to equity, the risk that the principal amount due can be written down to a lesser amount, and the general risks applicable to fixed income investments, including interest rate risk, credit risk, market risk and liquidity risk, any of which could result in losses to the Fund. CoCos may experience a loss absorption mechanism trigger event, which would likely be the result of, or related to, the deterioration of the issuer's financial condition (e.g., a decrease in the issuer's capital ratio) and status as a going concern. In such a case, with respect to contingent convertible securities that provide for conversion into common stock upon the occurrence of the trigger event, the market price of the issuer's common stock received by the Fund will have likely declined, perhaps substantially, and may continue to decline, which may adversely affect the Fund's net asset value.

When market quotations are not readily available or are deemed to be unreliable, the Fund values its investments at fair value as determined in good faith pursuant to policies and procedures approved by the Board of Trustees. See "Net Asset Value." Fair value pricing may require subjective determinations about the value of a security or other asset. As a result, there can be no assurance that fair value pricing will result in adjustments to the prices of securities or other assets, or that fair value pricing will reflect actual market value, and it is possible that the fair value determined for a security or other asset will be materially different from quoted or published prices, from the prices used by others for the same security or other asset and/or from the value that actually could be or is realized upon the sale of that security or other asset.

The Fund may engage in practices and strategies that will result in exposure to fluctuations in foreign exchange rates, in which case the Fund will be subject to foreign currency risk. The Fund's Common Shares are priced in U.S. dollars and the distributions paid by the Fund to Common Shareholders

are paid in U.S. dollars. However, a substantial portion of the Fund's assets may be denominated directly in foreign (non-U.S.) currencies or in securities that trade in, and receive revenues in, foreign (non-U.S.) currencies, or in derivatives that provide exposure to foreign (non-U.S.) currencies, it will be subject to the risk that those currencies will decline in value relative to the U.S. dollar, or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency being hedged.

Currency rates in foreign (non-U.S.) countries may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates, rates of inflation, balance of payments and governmental surpluses or deficits, intervention (or the failure to intervene) by U.S. or foreign (non-U.S.) governments, central banks or supranational entities such as the International Monetary Fund, or by the imposition of currency controls or other political developments in the United States or abroad. These fluctuations may have a significant adverse impact on the value of the Fund's portfolio and/or the level of Fund distributions made to Common Shareholders. As noted above, the Fund may (but is not required to) seek exposure to foreign currencies, or attempt to hedge exposure to reduce the risk of loss due to fluctuations in currency exchange rates relative to the U.S. dollar. There is no assurance, however, that these strategies will be available or will be used by the Fund or, if used, that they will be successful. As a result, the Fund's investments in foreign currency-denominated securities may reduce the returns of the Fund.

Currency risk may be particularly high to the extent that the Fund invests in foreign (non-U.S.) currencies or engages in foreign currency transactions that are economically tied to emerging market countries. These currency transactions may present market, credit, currency, liquidity, legal, political and other risks different from, or greater than, the risks of investing in developed foreign (non-U.S.) currencies or engaging in foreign currency transactions that are economically tied to developed foreign countries.

The Fund may invest in debt securities issued or guaranteed by agencies, instrumentalities and sponsored enterprises of the U.S. Government. Some U.S. Government securities, such as U.S. Treasury bills, notes and bonds, and mortgage-related securities guaranteed by the Government National Mortgage Association ("GNMA"), are supported by the full faith and credit of the United States; others, such as those of the Federal Home Loan Banks ("FHLBs") or Federal Home Loan Mortgage Corporation ("FHLMC"), are supported by the right of the issuer to borrow from the U.S. Treasury; others, such as those of the Federal National Mortgage Association ("FNMA"), are supported by the discretionary authority of the U.S. Government to purchase the agency's obligations; and still others are supported only by the credit of the agency, instrumentality or corporation. Although legislation has been enacted to support certain government sponsored entities, including the FHLBs, FHLMC and the FNMA, there is no assurance that the obligations of such entities will be satisfied in full, or that such obligations will not decrease in value or default. It is difficult, if not impossible, to predict the future political, regulatory or economic changes that could impact the government sponsored entities and the values of their related securities or obligations. In addition, certain governmental entities, including FNMA and FHLMC, have been subject to regulatory scrutiny regarding their accounting policies and practices and other concerns that may result in legislation, changes in regulatory oversight and/or other consequences that could adversely affect the credit quality, availability or investment character of securities issued by these entities. See "Investment Objective and Policies —Mortgage-Related and Other Asset-Backed Securities" in the Statement of Additional Information. U.S. Government debt securities generally involve lower levels of credit risk than other types of debt securities of similar maturities, although, as a result, the yields available from U.S. Government debt securities are generally lower than the yields available from such other securities. Like other debt securities, the values of U.S. Government securities change as interest rates fluctuate. Fluctuations in the value of portfolio securities will not affect interest income on existing portfolio securities but will be reflected in the Fund's NAV.

The Fund's investments in debt obligations of foreign (non-U.S.) governments or their sub-divisions, agencies and government sponsored enterprises and obligations of international agencies and supranational entities (together "Foreign Government Securities") can involve a high degree of risk. The foreign governmental entity that controls the repayment of debt may not be able or willing to repay the principal and/or interest when due in accordance with the terms of such debt. A governmental entity's willingness or ability to repay principal and interest due in a timely manner may be affected by, among other factors, its cash flow situation, the extent of its foreign reserves, the availability of sufficient foreign exchange on the date a payment is due, the relative size of the debt service burden to the economy as a whole, the governmental entity's policy towards the International Monetary Fund and the political constraints to which a governmental entity may be subject. Foreign governmental entities also may be dependent on expected disbursements from other governments, multilateral agencies and others abroad to reduce principal and interest arrearages on their debt. The commitment on the part of these governments, agencies and others to make such disbursements may be conditioned on the implementation of economic reforms and/or economic performance and the timely service of such debtor's obligations. Failure to implement such reforms, achieve such levels of economic performance or repay principal or interest when due may result in the cancellation of such third parties' commitments to lend funds to the foreign governmental entity, which may further impair such debtor's ability or willingness to timely service its debts. Consequently, foreign governmental entities may default on their debt. Holders of Foreign Government Securities may be requested to participate in the rescheduling of such debt and to extend further loans to governmental entities. In the event of a default by a governmental entity, there may be few or no effective legal remedies for collecting on such debt. These risks are particularly severe with respect to the Fund's investments in Foreign Government Securities of emerging market countries. See "Principal Risks of the Fund—Emerging Markets Risk." Among other risks, if the Fund's investments in Foreign Government Securities issued by an emerging market country need to be liquidated quickly, the Fund could sustain significant transaction costs. Also, governments in many emerging market countries participate to a significant degree in their economies and securities markets, which may impair investment and economic growth, and which may in turn diminish the value of the Fund's holdings in emerging

market Foreign Government Securities and the currencies in which they are denominated and/or pay revenues.

There are no direct or indirect government or agency guarantees of payments in pools created by nongovernmental issuers. Privately-issued mortgage-related securities are also not subject to the same underwriting requirements for the underlying mortgages that are applicable to those mortgage-related securities that have a government or government-sponsored entity guarantee.

Privately-issued mortgage-related securities are not traded on an exchange and there may be a limited market for the securities, especially when there is a perceived weakness in the mortgage and real estate market sectors. Without an active trading market, mortgage-related securities held in the Fund's portfolio may be particularly difficult to value because of the complexities involved in assessing the value of the underlying mortgage loans.

The mortgage markets in the United States and in various foreign countries have experienced extreme difficulties in the past that adversely affected the performance and market value of certain of the Fund's mortgage-related investments. Delinquencies and losses on residential and commercial mortgage loans (especially subprime and second-lien mortgage loans) generally increased during that period and may increase again, and a decline in or flattening of housing and other real property values (as has been experienced during that period and may continue to be experienced in many real estate markets) may exacerbate such delinquencies and losses. Borrowers with adjustable rate mortgage loans are more sensitive to changes in interest rates, which affect their monthly mortgage payments, and may be unable to secure replacement mortgages at comparably low interest rates. Also, a number of mortgage loan originators have experienced serious financial difficulties or bankruptcy in recent periods. Owing largely to the foregoing, reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen.

The Investment Manager manages the Fund without regard generally to restrictions on portfolio turnover. Trading in fixed income securities does not generally involve the payment of brokerage commissions, but does involve indirect transaction costs. Higher portfolio turnover involves correspondingly greater expenses to the Fund, including brokerage commissions or dealer mark-ups and other transaction costs on the sale of securities and reinvestments in other securities. The higher the rate of portfolio turnover of the Fund, the higher these transaction costs borne by the Fund generally will be. Such sales may result in realization of taxable capital gains (including short-term capital gains, which are generally taxed to shareholders at ordinary income tax rates when distributed net of short-term capital losses and net long-term capital losses), and may adversely affect the Fund's after-tax returns. See "Tax Matters."

In managing the Fund, PIMCO may from time to time have the opportunity to receive material, non-public information ("Confidential Information") about the issuers of certain investments, including, without limit, senior floating rate loans, other loans and related investments being considered for acquisition by the Fund or held in the Fund's portfolio. For example, an issuer of privately placed loans considered by the Fund may offer to provide PIMCO with financial information and related documentation regarding the issuer that is not publicly available. Pursuant to applicable policies and procedures, PIMCO may (but is not required to) seek to avoid receipt of Confidential Information from the issuer so as to avoid possible restrictions on its ability to purchase and sell investments on behalf of the Fund and other clients to which such Confidential Information relates (e.g., other securities issued by the bank used in the example above). In such circumstances, the Fund (and other PIMCO clients) may be disadvantaged in comparison to other investors, including with respect to the price the Fund pays or receives when it buys or sells an investment. Further, PIMCO's and the Fund's abilities to assess the desirability of proposed consents, waivers or amendments with respect to certain investments may be compromised if they are not privy to available Confidential Information. PIMCO may also determine to receive such Confidential Information in certain circumstances under its applicable policies and procedures. If PIMCO intentionally or unintentionally comes into possession of Confidential Information, it may be unable, potentially for a substantial period of time, to purchase or sell investments to which such Confidential Information relates.

An investment in the Fund, like any fund, can involve operational risks arising from factors such as processing errors, human errors, inadequate or failed internal or external processes, failures in systems and technology, changes in personnel and errors caused by third-party service providers. The occurrence of any of these failures, errors or breaches could result in a loss of information, regulatory scrutiny, reputational damage or other events, any of which could have a material adverse effect on the Fund. While the Fund seeks to minimize such events through controls and oversight, there may still be failures that could cause losses to the Fund.

As the use of technology has become more prevalent in the course of business, the Fund has become potentially more susceptible to operational and informational security risks resulting from breaches in cyber security. A breach in cyber security refers to both intentional and unintentional cyber events that may, among other things, cause the Fund to lose proprietary information, suffer data corruption and/or destruction or lose operational capacity, result in the unauthorized release or other misuse of confidential informaiton, or otherwise disrupt normal business operations. Cyber security breaches may involve unauthorized access to the Fund's digital information systems (e.g., through "hacking" or malicious software coding), but may also result from outside attacks such as denial-of-service attacks (i.e., efforts to make network services unavailable to intended users). In addition, cyber

security breaches involving the Fund's third party service providers (including but not limited to advisers, administrators, transfer agents, custodians, distributors and other third parties), trading counterparties or issuers in which the Fund invests can also subject the Fund to many of the same risks associated with direct cyber security breaches. Moreover, cyber security breaches involving trading counterparties or issuers in which the Fund invests could adversely impact such counterparties or issuers and cause the Fund's investments to lose value.

Cyber security failures or breaches may result in financial losses to the Fund and its shareholders. These failures or breaches may also result in disruptions to business operations, potentially resulting in financial losses; interference with the Fund's ability to calculate its NAV, process shareholder transactions or otherwise transact business with shareholders; impediments to trading; violations of applicable privacy and other laws; regulatory fines; penalties; reputational damage; reimbursement or other compensation costs; additional compliance and cyber security risk management costs and other adverse consequences. In addition, substantial costs may be incurred in an attempt to prevent any cyber incidents in the future.

Like with operational risk in general, the Fund has established risk management systems and business continuity plans designed to reduce the risks associated with cyber security. However, there are inherent limitations in these plans and systems, including that certain risks may not have been identified, in large part because different or unknown threats may emerge in the future. As such, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers in which the Fund may invest, trading counterparties, or third party service providers to the Fund. There is also a risk that cyber security breaches may not be detected. The Fund and its Common Shareholders could be negatively impacted as a result.

As noted above, the Fund may invest in the debt securities of financially distressed issuers, including those that are in default or the issuers of which are in bankruptcy. Investments in the securities of financially distressed issuers involve substantial risks. These securities may present a substantial risk of default or may be in default at the time of investment. In addition, these securities may fluctuate more in price, and are typically less liquid than other higher-rated debt securities. The Fund also will be subject to significant uncertainty as to when, and in what manner, and for what value obligations evidenced by securities of financially distressed issuers will eventually be satisfied (e.g., through a liquidation of the issuer's assets, an exchange offer or plan of reorganization, or a payment of some amount in satisfaction of the obligation). Defaulted obligations might be repaid only after lengthy workout or bankruptcy proceedings, during which the issuer might not make any interest or other payments. In any such proceeding relating to a defaulted obligation, the Fund may lose its entire investment or may be required to accept cash or securities with a value substantially less than its original investment. Moreover, any securities received by the Fund upon completion of a workout or bankruptcy proceeding may be illiquid, speculative, or restricted as to resale. Similarly, if the Fund participates in negotiations with respect to any exchange offer or plan of reorganization with respect to the securities of a distressed issuer, the Fund may be restricted from disposing of such securities. To the extent that the Fund becomes involved in such proceedings, the Fund may have a more active participation in the affairs of the issuer than that assumed generally by an investor. The Fund may incur additional expenses to the extent it is required to seek recovery upon a default in the payment of principal or interest on its portfolio holdings.

Also among the risks inherent in investments in a troubled issuer is that it frequently may be difficult to obtain information as to the true financial condition of such issuer. PIMCO's judgments about the credit quality of a financially distressed issuer and the relative value of its securities may prove to be wrong.

Potential Conflicts of Interest Risk—Allocation of Investment Opportunities

The Investment Manager is involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Fund. The Investment Manager may provide investment management services to other funds and discretionary managed accounts that follow an investment program similar to that of the Fund. Subject to the requirements of the 1940 Act, the Investment Manager intends to engage in such activities and may receive compensation from third parties for its services. The results of the Fund's investment activities may differ from those of the Fund's affiliates, or another account managed by the Fund's affiliates, and it is possible that the Fund could sustain losses during periods in which one or more of the Fund's affiliates and/or other accounts achieve profits on their trading for proprietary or other accounts. The Investment Manager has adopted policies and procedures reasonably designed to allocate investment opportunities on a fair and equitable basis over time.

Legal, tax and regulatory changes could occur and may adversely affect the Fund and its ability to pursue its investment strategies and/or increase the costs of implementing such strategies. New (or revised) laws or regulations may be imposed by the U.S. Commodity Futures Trading Commission ("CFTC"), the SEC, the U.S. Internal Revenue Service ("IRS"), the U.S. Federal Reserve or other banking regulators, other governmental regulatory authorities or self-regulatory organizations that supervise the financial markets that could adversely affect the Fund. In particular, these agencies are implementing a variety of new rules pursuant to financial reform legislation in the United States. The EU (and some other countries) are implementing similar requirements. The Fund also may be adversely affected by changes in the enforcement or interpretation of existing statutes and rules by these governmental regulatory authorities or self-regulatory organizations.

In addition, the securities and futures markets are subject to comprehensive statutes, regulations and margin requirements. The CFTC, the SEC, the Federal Deposit Insurance Corporation, other regulators and self-regulatory organizations and exchanges are authorized under these statutes, regulations and otherwise to take extraordinary actions in the event of market emergencies. The Fund and the Investment Manager have historically been eligible for exemptions from certain regulations. However,

there is no assurance that the Fund and the Investment Manager will continue to be eligible for such exemptions. The CFTC and certain futures exchanges have established limits, referred to as "position limits," on the maximum net long or net short positions which any person may hold or control in particular options and futures contracts.

The CFTC has proposed position limits for certain swaps. All positions owned or controlled by the same person or entity, even if in different accounts, may be aggregated for purposes of determining whether the applicable position limits have been exceeded. Thus, even if the Fund does not intend to exceed applicable position limits, it is possible that different clients managed by the Investment Manager and their related parties may be aggregated for this purpose. Therefore it is possible that the trading decisions of Investment Manager may have to be modified and that positions held by the Fund may have to be liquidated in order to avoid exceeding such limits. The modification of investment decisions or the elimination of open positions, if it occurs, may adversely affect the performance of the Fund.

The SEC has in the past adopted interim rules requiring reporting of all short positions above a certain de minimis threshold and may adopt rules requiring monthly public disclosure in the future. In addition, other non-U.S. jurisdictions where the Fund may trade have adopted reporting requirements. If the Fund's short positions or its strategy become generally known, it could have a significant effect on the Investment Manager's ability to implement its investment strategy. In particular, it would make it more likely that other investors could cause a short squeeze in the securities held short by the Fund forcing the Fund to cover its positions at a loss. Such reporting requirements may also limit the Investment Manager's ability to access management and other personnel at certain companies where the Investment Manager seeks to take a short position. In addition, if other investors engage in copycat behavior by taking positions in the same issuers as the Fund, the cost of borrowing securities to sell short could increase drastically and the availability of such securities to the Fund could decrease drastically. Such events could make the Fund unable to execute its investment strategy. In addition, if the SEC were to adopt restrictions regarding short sales, they could restrict the Fund's ability to engage in short sales in certain circumstances, and the Fund may be unable to execute its investment strategies as a result.

The SEC and regulatory authorities in other jurisdictions may adopt (and in certain cases, have adopted) bans on short sales of certain securities in response to market events. Bans on short selling may make it impossible for the Fund to execute certain investment strategies and may have a material adverse effect on the Fund's ability to generate returns.

Recently adopted rules implementing the credit risk retention requirements of the Dodd-Frank Wall Street Reform and Consumer Protection Act (the "Dodd-Frank Act"), for asset-backed securities will require the sponsor of certain securitization vehicles (or a majority owned affiliate of such sponsor) to retain, and to refrain from transferring, selling, conveying to a third party, or hedging 5% of the credit risk in assets transferred, sold, or conveyed through the issuance of the asset-backed securities of such vehicle, subject to certain exceptions. The rules apply to offerings of residential mortgage-backed securities (RMBS) occurring on and after December 24, 2015 and to offerings of other types of asset-backed securities occurring on and after December 24, 2016, subject to certain exceptions. In addition, a refinancing of, or a significant amendment to, a securitization that closed prior to such date may in certain cases result in the application of the rules to a securitization that was previously not subject to the Dodd-Frank risk retention requirements. The impact of the risk retention rules on the securitization markets is uncertain. These requirements may increase the costs to originators, securitizers, and, in certain cases, collateral managers of securitization vehicles in which the Fund may invest, which costs could be passed along to such Fund as an investor in such vehicles. In addition, the costs imposed by the risk retention rules on originators, securitizers and/or collateral managers may result in a reduction of the number of new offerings of asset-backed securities and thus in fewer investment opportunities for the Fund. A reduction in the number of new securitizations could also reduce liquidity in the markets for certain types of financial assets that are typically held by securitization vehicles, which in turn could negatively affect the returns on the Fund's investment in asset-backed securities.

The CFTC has adopted regulations that subject registered investment companies and their investment advisers to regulation by the CFTC if the registered investment company invests more than a prescribed level of its liquidation value in futures, options on futures or commodities swaps, or other financial instruments regulated under the Commodity Exchange Act ("commodity interests"), or if the Fund markets itself as providing investment exposure to such instruments. The Investment Manager is registered with the CFTC and as a "commodity pool operator" ("CPO") under the Commodity Exchange Act ("CEA") with respect to the Fund, and is a member oft he National Futures Association ("NFA") in such capacity. Under CFTC rules, certain mandated disclosure, reporting and recordkeeping obligations will apply to the Investment Manager with respect to the Fund. Compliance with the CFTC's regulatory requirements could increase the Fund's expenses, adversely affecting the Fund's total return.

The Fund may invest in structured products, including, structured notes, credit-linked notes and other types of structured products. Holders of structured products bear risks of the underlying investments, index or reference obligation and are subject to counterparty risk. The Fund may have the right to receive payments only from the structured product, and generally does not have direct rights against the issuer or the entity that sold the assets to be securitized. While certain structured products enable the investor to acquire interests in a pool of securities without the brokerage and other expenses associated with directly holding the same securities, investors in structured products generally pay their share of the structured product's administrative and other expenses. Although it is difficult to predict whether the prices of indices and securities underlying structured products will rise or fall, these prices (and, therefore, the prices of structured products) are generally influenced by the same types of political and economic events that affect issuers of securities and capital markets generally. If the issuer of a structured product uses shorter term financing to purchase longer term securities, the issuer may be forced to sell its securities

at below market prices if it experiences difficulty in obtaining such financing, which may adversely affect the value of the structured products owned by the Fund. Structured products generally entail risks associated with derivative instruments. See "Principal Risks of the Fund—Derivatives Risk."

The Fund may invest in CLOs. A CLO is a trust typically collateralized by a pool of loans issued by banks, corporations or any other public or private entity or person, which may include, among others, domestic and foreign senior secured loans, senior unsecured loans and subordinate or mezzanine loans, including loans that may be rated below investment grade or equivalent unrated loans. CLOs may charge management fees and administrative expenses. The cash flows from the trust are split into two or more portions, called tranches, varying in risk and yield. The riskiest portion is the equity tranche which generally bears losses in connection with the first defaults, if any, on the bonds or loans in the trust and serves to provide some measure of protection to the other, more senior tranches from defaults. A senior tranche from a CLO trust typically has higher ratings and lower yields than the underlying securities, and can be rated investment grade. Despite the protection from the equity tranche, CLO tranches can experience substantial losses due to actual defaults, increased sensitivity to defaults due to collateral default and disappearance of protecting tranches, market anticipation of defaults and aversion to CLO securities as a class. The risks of an investment in a CLO depend largely on the type of the collateral securities and the class of the CLO in which the Fund invests. Normally, CLOs are privately offered and sold, and thus are not registered under the securities laws. As a result, investments in CLOs may be characterized by the Fund as illiquid securities; however, an active dealer market may exist for CLOs allowing a CLO to qualify under Rule 144A under the 1933 Act. In addition to the normal risks associated with debt instruments (e.g., interest rate risk and credit risk), CLOs carry additional risks including, but not limited to: (i) the possibility that distributions from the collateral will not be adequate to make interest or other payments; (ii) the quality of the collateral may decline in value or default; (iii) the risk that the Fund may invest in CBOs, CLOs or other CDOs that are subordinate to other classes; and (iv) the complex structure of the security may not be fully understood at the time of investment and may produce disputes with the issuer or others and may produce unexpected investment results.

Certain broker-dealers may be considered to be affiliated persons of the Fund and/or the Investment Manager due to their possible affiliations with Allianz SE, the ultimate parent of the Investment Manager. Absent an exemption from the SEC or other regulatory relief, the Fund is generally precluded from effecting certain principal transactions with affiliated brokers, and its ability to purchase securities being underwritten by an affiliated broker or a syndicate including an affiliated broker, or to utilize affiliated brokers for agency transactions, is subject to restrictions. This could limit the Fund's ability to engage in securities transactions and take advantage of market opportunities.

The Fund's Amended and Restated Agreement and Declaration of Trust (the "Declaration") includes provisions that could limit the ability of other entities or persons to acquire control of the Fund or to convert the Fund to open-end status. See "Anti-Takeover and Other Provisions in the Declaration of Trust." These provisions in the Declaration could have the effect of depriving the Common Shareholders of opportunities to sell their Common Shares at a premium over the then-current market price of the Common Shares or at NAV.

Although the Fund may seek to maintain stable distributions, the Fund's distribution rates may be affected by numerous factors, including but not limited to changes in realized and projected market returns, fluctuations in market interest rates, Fund performance, and other factors. There can be no assurance that a change in market conditions or other factors will not result in a change in the Fund's distribution rate or that the rate will be sustainable in the future.

For instance, during periods of low or declining interest rates, the Fund's distributable income and dividend levels may decline for many reasons. For example, the Fund may have to deploy uninvested assets (whether from purchases of Fund shares, proceeds from matured, traded or called debt obligations or other sources) in new, lower yielding instruments. Additionally, payments from certain instruments that may be held by the Fund (such as variable and floating rate securities) may be negatively impacted by declining interest rates, which may also lead to a decline in the Fund's distributable income and dividend levels.

The following table is intended to assist investors in understanding the fees and expenses (annualized) that an investor in Common Shares of the Fund would bear, directly or indirectly, as a result of an offering. The table reflects the use of leverage attributable to the Fund's outstanding Preferred Shares and reverse repurchase agreements in an amount equal to 29.53% of the Fund's total managed assets (including assets attributable to such leverage), which reflects approximately the percentage of the Fund's total managed assets attributable to such leverage as of January 31, 2018, and shows Fund expenses as a percentage of net assets attributable to Common Shares. The percentage above and information do not reflect the Fund's use of other forms of economic leverage, such as credit default swaps or other derivative instruments. The table and example below are based on the Fund's capital structure as of January 31, 2018. The extent of the Fund's assets attributable to leverage following an offering, and the Fund's associated expenses, are likely to vary (perhaps significantly) from these assumptions.

1 In the event that the Common Shares to which this prospectus relates are sold to or through underwriters or dealer managers, a corresponding prospectus supplement will disclose the applicable sales load and/or commission.

2 The related prospectus supplement will disclose the estimated amount of offering expenses, the offering price and the offering expenses borne by the Fund and indirectly by all of its Common Shareholders as a percentage of the offering price.

3 You will pay brokerage charges if you direct your broker or the plan agent to sell your Common Shares that you acquired pursuant to a dividend reinvestment plan. You may also pay a pro rata share of brokerage commissions incurred in connection with open-market purchases pursuant to the Fund's Dividend Reinvestment Plan. See "Dividend Reinvestment Plan."

1 Management Fees include fees payable to the Investment Manager for advisory services and for supervisory, administrative and other services. The Fund pays for the advisory, supervisory and administrative services it requires under what is essentially an all-in fee structure (the "unified management fee"). Pursuant to an investment management agreement, PIMCO is paid a Management Fee of 0.65% based on the Fund's average daily net assets (including daily net assets attributable to any preferred shares of the Fund that may be outstanding). The Fund (and not PIMCO) will be responsible for certain fees and expenses, reflected in the table above, that are not covered by the unified management fee under the investment management agreement. Please see "Management of the Fund— Investment Management Agreement" for an explanation of the unified management fee.

2 Reflects the Fund's outstanding Preferred Shares as of January 31, 2018, which represented 13.77% of the Fund's total managed assets (including the liquidation preference of outstanding Preferred Shares and assets attributable to reverse repurchase agreements) as of that date, at an estimated annual dividend rate to the Fund of 2.82% (based on the Preferred Share dividend rate as of January 31, 2018) and assumes the Fund will continue to pay Preferred Share dividends at the "maximum applicable rate" called for under the Fund's Bylaws due to the ongoing failure of auctions for the ARPS. The actual dividend rate paid on the ARPS will vary over time in accordance with variations in market interest rates. See "Use of Leverage" and "Description of Capital Structure."

3 Reflects the Fund's use of leverage in the form of reverse repurchase agreements as of January 31, 2018, which represented 15.76% of the Fund's total managed assets (including assets attributable to reverse repurchase agreements) as of that date, at an estimated annual interest rate cost to the Fund of 1.85% (based on market interest rates as of January 31, 2018). See "Leverage—Effects of Leverage." The actual amount of interest expense borne by the Fund will vary over time in accordance with the level of the Fund's use of reverse repurchase agreements, dollar rolls and/or borrowings and variations in market interest rates. Borrowing expense is required to be treated as an expense of the Fund for accounting purposes. Any associated income or gains (or losses) realized from leverage obtained through such instruments is not reflected in the Annual Expenses table above, but would be reflected in the Fund's performance results.

4 Other expenses are estimated for the Fund's current fiscal year ending July 31, 2018.

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 1.66% of net assets attributable to Common Shares in years 1 through 10 (assuming outstanding Preferred Shares and reverse repurchase agreements representing 29.53% of the Fund's total managed assets) and (3) a 5% annual return⁽¹⁾:

⁽¹⁾ The example above should not be considered a representation of future expenses. Actual expenses may be higher or lower than those shown. The example assumes that the estimated Interest Payments on Borrowed Funds, Dividend Cost on Preferred Shares and Other Expenses set forth in the Annual Expenses table are accurate, that the rate listed under Total Annual Expenses remains the same each year and that all dividends and distributions are reinvested at NAV. Actual expenses may be greater or less than those assumed. Moreover, the Fund's actual rate of return may be greater or less than the hypothetical 5% annual return shown in the example. The example does not include commissions or estimated offering expenses, which would cause the expenses shown in the example to increase. In connection with an offering of Common Shares, the prospectus supplement will set forth an example including sales load and estimated offering costs.

The information in the table below for the fiscal years ended July 31, 2017 and July 31, 2016, the fiscal period ended July 31, 2015⁽¹⁾ and the fiscal years ended November 30, 2014, 2013, and 2012 is derived from the Fund's financial statements for the fiscal year ended July 31, 2017 audited by PricewaterhouseCoopers LLP ("PwC"), whose report on such financial statements is contained in the Fund's July 31, 2017 Annual Report and is incorporated by reference into the Statement of Additional Information. The information in the table below for the fiscal years ended November 30, 2011, November 30, 2010, 2009 and 2008 is derived from the Fund's financial statements for the fiscal year ended November 30, 2011.

1 On December 16, 2014, the Board approved a change of the Fund's fiscal year end from November 30 to July 31. Information is provided for the "stub" period from December 1, 2014
through the Fund's new fiscal year end of July 31, 2015.

The following table sets forth certain information regarding the Fund's outstanding ARPS as of the end of the last ten of the Fund's fiscal years.

1 "Asset Coverage per Preferred Share" means the ratio that the value of the total assets of the Fund, less all liabilities and indebtedness not represented by ARPS, bears to the aggregate of the involuntary liquidation preference of ARPS , expressed as a dollar amount per ARPS.

2 "Involuntary Liquidating Preference per ARPS" means the amount to which a holder of ARPS would be entitled upon the involuntary liquidation of the Fund in preference to the Common Shareholders, expressed as a dollar amount per Preferred Share.

3 The ARPS have no readily ascertainable market value. As discussed herein under "Use of Leverage," auctions for the ARPS have failed since February 2008, there is currently no active trading market for the ARPS and the Fund is not able to reliably estimate what their value would be in a third-party market sale.

4 On December 16, 2014, the Board approved a change of the Fund's fiscal year end from November 30 to July 31. Information is provided for the "stub" period from December 1, 2014 through the Fund's new fiscal year end of July 31, 2015.

The net proceeds of an offering will be invested in accordance with the Fund's investment objective and policies as set forth below. It is currently anticipated that the Fund will be able to invest substantially all of the net proceeds of an offering in accordance with its investment objective and policies within approximately 30 days of receipt by the Fund, depending on the amount and timing of proceeds available to the Fund as well as the availability of investments consistent with the Fund's investment objective and policies, and except to the extent proceeds are held in cash to pay dividends or expenses, or for temporary defensive purposes. Pending such investment, it is anticipated that the proceeds of an offering will be invested in high grade, short-term securities, credit linked trust certificates, and/or high yield securities index future contracts or similar derivative instruments designed to give the Fund exposure to the securities and markets in which it intends to invest while the Investment manager selects specific investments.

The Fund is a diversified, closed-end management investment company. The Fund was organized as a Massachusetts business trust on September 13, 2002, pursuant to an Agreement and Declaration of Trust governed by the laws of the Commonwealth of Massachusetts. The Fund commenced operations on December 27, 2002, following the initial public offering of its Common Shares. Effective February 1, 2012, the Fund changed its name from PIMCO Corporate Opportunity Fund to its current name, PIMCO Corporate & Income Opportunity Fund.

The Fund cannot change its investment objective without the approval of the holders of a "majority of the outstanding" Common Shares and any Preferred Shares voting together as a single class, and of the holders of a "majority of the outstanding" Preferred Shares voting as a separate class. A "majority of the outstanding" shares (whether voting together as a single class or voting as a separate class) means (i) 67% or more of such shares present at a meeting, if the holders of more than 50% of those shares are present or represented by proxy, or (ii) more than 50% of such shares, whichever is less. See "Description of Shares—Preferred Shares—Voting Rights" for additional information with respect to the voting rights of holders of Preferred Shares. The Fund may not change its policy to invest at least 80% of its total assets in a combination of corporate debt obligations of varying maturities, other corporate income-producing securities, and income-producing securities of non-corporate issuers unless it provides shareholders with at least 60 days' written notice of such change.

Dynamic Allocation Strategy. On behalf of the Fund, the Investment Manager employs an active approach to allocation among multiple fixed income sectors based on, among other things, market conditions, valuation assessments, economic outlook, credit market trends and other economic factors. With PIMCO's macroeconomic analysis as the basis for top-down investment decisions, including geographic and credit sector emphasis, the Fund focuses on seeking the best income generating investment ideas across multiple fixed income sectors, with an emphasis on seeking opportunities in developed and emerging global credit markets. PIMCO may choose to focus on particular countries/regions (e.g., U.S. vs. foreign), asset classes, industries and sectors to the exclusion of others at any time and from time to time based on market conditions and other factors. The relative value assessment within fixed-income sectors draws on PIMCO's regional and sector specialist expertise. The Fund will observe various investment guidelines as summarized below.

Investment Selection Strategies. Once the Fund's top-down, portfolio positioning decisions have been made as described above, PIMCO selects particular investments for the Fund by employing a bottom-up, disciplined credit approach which is driven by fundamental, independent research within each sector/asset class represented in the Fund, with a focus on identifying securities and other instruments with solid and/or improving fundamentals.

Moody's, or that are unrated but determined by PIMCO to be of comparable quality to securities so rated. The Fund may invest without limit in mortgage-related and other asset-backed securities regardless of rating (i.e., of any credit quality). Subject to this 20% restriction, the Fund may invest in issuers of any credit quality (including bonds in the lowest ratings categories) if PIMCO determines that the particular obligation is undervalued or offers an attractive yield relative to its risk profile. The Fund may also invest up to 5% of its total assets in defaulted bonds when PIMCO believes that the issuer's potential revenues and prospects for recovery are favorable, except that the Fund may invest in mortgage-related and other asset-backed securities without regard to this limit, subject to the Fund's other investment policies. For purposes of applying the foregoing policies, in the case of securities with split ratings (i.e., a security receiving two different ratings from two different rating agencies), the Fund will apply the higher of the applicable ratings. Subject to the aforementioned investment restrictions, the Fund may invest in securities of stressed issuers, which include securities at risk of being in default as to the repayment of principal and/or interest at the time of acquisition by the Fund or that are rated in the lower rating categories by one or more nationally recognized statistical rating organizations (for example, Ca or lower by Moody's or CC or lower by S&P or Fitch) or, if unrated, are determined by PIMCO to be of comparable quality. Debt instruments of below investment grade quality are regarded as having predominantly speculative characteristics with respect to capacity to pay interest and to repay principal, and are commonly referred to as "high yield" securities or "junk bonds." Debt instruments in the lowest investment grade category also may be considered to possess some speculative characteristics. The Fund may, for hedging, investment or leveraging purposes, make use of credit default swaps, which are contracts whereby one party makes periodic payments to a counterparty in exchange for the right to receive from the counterparty a payment equal to the par (or other agreed-upon) value of a referenced debt obligation in the event of a default or other credit event by the issuer of the debt obligation. In addition, the Fund's use of credit default swaps and certain other derivative instruments will be limited by the Fund's 20% limit on illiquid investments to the extent they are determined to be illiquid.

Independent Credit Analysis. PIMCO relies primarily on its own analysis of the credit quality and risks associated with individual debt instruments considered for the Fund, rather than relying exclusively on rating agencies or third-party research. The Fund's portfolio managers utilize this information in an attempt to minimize credit risk and to identify issuers, industries or sectors that are undervalued or that offer attractive yields relative to PIMCO's assessment of their credit characteristics. This aspect of PIMCO's capabilities will be particularly important to the extent that the Fund invests in high yield securities and in securities of emerging market issuers.

Duration Management. It is expected that the Fund normally will have a short to intermediate average portfolio duration (i.e., within a zero to eight year range), as calculated by PIMCO, although it may be shorter or longer at any time or from time to time depending on market conditions and other factors. While the Fund seeks to maintain a short to intermediate average portfolio duration, there is no limit on the maturity or duration of any individual security in which the Fund may invest. PIMCO believes that maintaining duration within this range offers flexibility and the opportunity for above-average returns while potentially limiting exposure to interest rate volatility and related risk. Duration is a measure used to determine the sensitivity of a security's price to changes in interest rates. The Fund's duration strategy may entail maintaining a negative average portfolio duration from time to time, which would potentially benefit the portfolio in an environment of rising market interest rates, but would generally adversely impact the portfolio in an environment of falling or neutral market interest rates. PIMCO may also utilize certain strategies, including without limit investments in structured notes or interest rate futures contracts or swap, cap, floor or collar transactions, for the purpose of reducing the interest rate sensitivity of the Fund's portfolio, although there is no assurance that it will do so or that such strategies will be successful.

Under normal market conditions, the Fund seeks to achieve its investment objective by investing at least 80% of its total assets in a combination of corporate debt obligations of varying maturities, other corporate income-producing securities, and income-producing securities of non-corporate issuers, such as U.S. Government securities, municipal securities and mortgage-backed and other asset-backed securities issued on a public or private basis. The Fund's investments in derivatives and other synthetic instruments that have economic characteristics similar to corporate debt obligations of varying maturities, other corporate income-producing securities, and income-producing securities of non-corporate issuers will be counted toward satisfaction of this 80% policy. The Fund will normally invest at least 25% of its total assets in corporate debt obligations and other corporate income-producing securities. Corporate income-producing securities include fixed-, variable- and floating-rate bonds, debentures, notes and other similar types of corporate debt instruments, such as preferred shares, convertible securities, bank loans and loan participations and assignments, payment-in-kind securities, zero-coupon bonds, bank certificates of deposit, fixed time deposits and bankers' acceptances, stressed debt securities, structured notes and other hybrid instruments. Certain corporate income-producing securities, such as convertible bonds, also may include the right to participate in equity appreciation, and PIMCO will generally evaluate those instruments based primarily on their debt characteristics. In satisfying the Fund's 80% Policy, the Fund may invest in mortgage-related securities, including mortgage pass-through securities, CMOs, commercial or residential mortgage-backed securities, mortgage dollar rolls, CMO residuals, SMBSs and other securities that directly or indirectly represent a participation in, or are secured by and payable from, mortgage loans on real property, debt instruments, including, without limitation, bonds, debentures, notes, and other debt securities of U.S. and foreign (non-U.S.) corporate and other issuers, including commercial paper; obligations of foreign governments or their sub-divisions, agencies and government sponsored enterprises and obligations of international agencies and supranational entities; municipal securities and other debt securities issued by states or local governments and their agencies, authorities and other government-sponsored enterprises, including taxable municipal securities (such as Build America Bonds); inflation-indexed bonds issued by both governments and corporations; structured notes, including hybrid or indexed securities; catastrophe bonds and other event-linked bonds; credit-

linked notes; structured credit products; bank loans (including, among others, senior loans, delayed funding loans, revolving credit facilities and loan participations and assignments); preferred securities and convertible debt securities (i.e., debt securities that may be converted at either a stated price or stated rate into underlying shares of common stock), including synthetic convertible debt securities (i.e., instruments created through a combination of separate securities that possess the two principal characteristics of a traditional convertible security, such as an income-producing security and the right to acquire an equity security) and contingent convertible securities. The Fund may invest in debt securities of stressed issuers. Subject to the investment limitations described under "Credit Quality" above, at any given time and from time to time, substantially all of the Fund's portfolio may consist of below investment grade securities. The Fund may invest in any level of the capital structure of an issuer of mortgage-backed or asset-backed securities, including the equity or "first loss" tranche. The rate of interest on an income-producing security may be fixed, floating or variable.

The Fund may invest up to 25% of its total assets (measured at the time of investment) in non-U.S. dollar denominated securities (of both developed and "emerging market" countries), including obligations of non-U.S. governments and their respective sub-divisions, agencies and government-sponsored enterprises. The Fund may invest without limit in short-term investment grade sovereign debt, including short-term investment grade sovereign debt issued by emerging market issuers. The Fund may invest up to 40% of its total assets in securities and instruments that are economically tied to "emerging market" countries other than investments in short-term investment grade sovereign debt issued by emerging market issuers, where as noted above there is no limit. The Fund may also invest directly in foreign currencies, including local emerging market currencies.

The Fund may invest in securities that have not been registered for public sale in the U.S. or relevant non-U.S. jurisdictions, including without limit securities eligible for purchase and sale pursuant to Rule 144A under the 1933 Act, or relevant provisions of applicable non-U.S. law, and other securities issued in private placements. The Fund may also invest in securities of other open- and closed-end investment companies, including, without limit, ETFs, and may invest in foreign ETFs. The Fund may invest in REITs. The Fund may invest in securities of companies with any market capitalization, including small and medium capitalizations.

Temporary defensive investments. Upon PIMCO's recommendation, for temporary defensive purposes and in order to keep the Fund's cash fully invested, including during the period in which the net proceeds of an offering are being invested, the Fund may deviate from its investment objective and policies and invest some or all of its net assets in investments of non-corporate issuers, including high quality, short-term debt securities. The Fund may not achieve its investment objective when it does so.

The following provides additional information regarding the types of securities and other instruments in which the Fund will ordinarily invest. A more detailed discussion of these and other instruments and investment techniques that may be used by the Fund is provided under "Investment Objective and Policies" in the Statement of Additional Information. The ability of the Fund to use some of the strategies discussed below and in the Statement of Additional Information, such as derivatives, is limited by the Rating Agency guidelines. See "Description of Capital Structure" below.

The Fund may invest in a wide variety of bonds of varying maturities issued by U.S. and foreign corporations and other business entities. Bonds are fixed or variable rate debt obligations, including bills, notes, debentures, money market instruments and similar instruments and securities. Bonds generally are used by corporations as well as governments and other issuers to borrow money from investors. The issuer pays the investor a fixed or variable rate of interest and normally must repay the amount borrowed on or before maturity. Certain bonds are "perpetual" in that they have no maturity date.

As noted above, the Fund will not normally invest more than 20% of its total assets in debt instruments, other than mortgage-related and other asset-backed securities, that are, at the time of purchase, rated CCC or lower by S&P and Fitch and Caa1 or lower by Moody's, or that are unrated but determined by PIMCO to be of comparable quality to securities so rated. The Fund may invest without limit in mortgage-related and other asset-backed securities regardless of rating (i.e., of any credit quality). For purposes of applying the foregoing policies, in the case of securities with split ratings (i.e., a security receiving two different ratings from two different rating agencies), the Fund will apply the higher of the applicable ratings. Subject to the aforementioned investment restrictions, the Fund may invest in securities of stressed or distressed issuers, which include securities at risk of being in default as to the repayment of principal and/or interest at the time of acquisition by the Fund or that are rated in the lower rating categories by one or more nationally recognized statistical rating organizations (for example, Ca or lower by Moody's or CC or lower by S&P or Fitch) or, if unrated, are determined by PIMCO to be of comparable quality. The Fund may also invest in defaulted securities and debtor-in-possession financings. Securities rated lower than Baa3 by Moody's or BBB-by S&P or Fitch, and unrated securities judged to be of comparable quality by PIMCO are sometimes referred to as "high yield" securities or "junk

bonds." High yield securities involve a greater degree of risk (in particular, a greater risk of default) than, and special risks in addition to the risks associated with, investment grade debt obligations. While offering a greater potential opportunity for capital appreciation and higher yields, high yield securities typically entail greater potential price volatility and may be less liquid than higher-rated securities. High yield securities may be regarded as predominantly speculative with respect to the issuer's continuing ability to make timely principal and interest payments. They also may be more susceptible to real or perceived adverse economic and competitive industry conditions than higher-rated securities. Debt securities in the lowest investment grade category also may be considered to possess some speculative characteristics by certain ratings agencies.

The market values of high yield securities tend to reflect individual developments of the issuer to a greater extent than do higher-quality securities, which tend to react mainly to fluctuations in the general level of interest rates. In addition, lower-quality debt securities tend to be more sensitive to general economic conditions. Certain emerging market governments that issue high yield securities in which the Fund may invest are among the largest debtors to commercial banks, foreign governments and supranational organizations, such as the World Bank, and may not be able or willing to make principal and/or interest payments as they come due.

Credit ratings and unrated securities. Rating agencies are private services that provide ratings of the credit quality of debt obligations. Appendix A to this prospectus describes the various ratings assigned to debt obligations by Moody's, S&P and Fitch. As noted in Appendix A, Moody's, S&P and Fitch may modify their ratings of securities to show relative standing within a rating category, with the addition of numerical modifiers (1, 2 or 3) in the case of Moody's, and with the addition of a plus (+) or minus (-) sign in the case of S&P and Fitch. Ratings assigned by a rating agency are not absolute standards of credit quality and do not evaluate market risks. Rating agencies may fail to make timely changes in credit ratings and an issuer's current financial condition may be better or worse than a rating indicates. The Fund will not necessarily sell a security when its rating is reduced below its rating at the time of purchase. PIMCO does not rely solely on credit ratings, and develops its own analysis of issuer credit quality. The ratings of a debt security may change over time. Moody's, S&P and Fitch monitor and evaluate the ratings assigned to securities on an ongoing basis. As a result, debt instruments held by the Fund could receive a higher rating (which would tend to increase their value) or a lower rating (which would tend to decrease their value) during the period in which they are held by the Fund.

The Fund may purchase unrated securities (which are not rated by a rating agency) if PIMCO determines that the security is of comparable quality to a rated security that the Fund may purchase. Unrated securities may be less liquid than comparable rated securities and involve the risk that PIMCO may not accurately evaluate the security's comparative credit quality, which could result in the Fund's portfolio having a higher level of credit and/or high yield risk than PIMCO has estimated or desires for the Fund, and could negatively impact the Fund's performance and/or returns. The Fund may invest a substantial portion of its assets in unrated securities and therefore may be particularly subject to the associated risks. Analysis of the creditworthiness of issuers of high yield securities may be more complex than for issuers of higher-quality debt obligations. To the extent that the Fund invests in high yield and/or unrated securities, the Fund's success in achieving its investment objective may depend more heavily on PIMCO's credit analysis than if Fund invested exclusively in higher-quality and rated securities.

The Fund may enter into credit default swaps for both investment and risk management purposes, as well as to add leverage to the Fund's portfolio. A credit default swap may have as reference obligations one or more securities that are not currently held by the Fund. The protection "buyer" in a credit default swap is generally obligated to pay the protection "seller" an upfront or a periodic stream of payments over the term of the contract provided that no credit event, such as a default, on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the "par value" (full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction. If the Fund is a buyer and no credit event occurs, the Fund may recover nothing if the swap is held through its termination date. However, if a credit event occurs, the buyer generally may elect to receive the full notional value of the swap from the seller, who, in turn, generally will recover an amount significantly lower than the equivalent face amount of the obligations of the reference entity, whose value may have significantly decreased, through (i) physical delivery of such obligations by the buyer, (ii) cash settlement or (iii) an auction process. As a seller, the Fund generally receives an upfront payment or a fixed rate of income throughout the term of the swap provided that there is no credit event. As the seller, the Fund would effectively add leverage to its portfolio because, in addition to its total net assets, the Fund would be subject to investment exposure on the notional amount of the swap.

The spread of a credit default swap is the annual amount the protection buyer must pay the protection seller over the length of the contract, expressed as a percentage of the notional amount. When spreads rise, market perceived credit risk rises and when spreads fall, market perceived credit risk falls. Wider credit spreads and decreasing market values, when compared to the notional amount of the swap, represent a deterioration of the referenced entity's credit soundness and a greater likelihood or risk of default or other credit event occurring as defined under the terms of the agreement. For credit default swaps on asset-backed securities and credit indices, the quoted market prices and resulting values, as well as the annual payment rate, serve as an indication of the current status of the payment/performance risk.

Credit default swaps involve greater risks than if the Fund had invested in the reference obligation directly since, in addition to general market risks, credit default swaps are subject to illiquidity risk, counterparty risk and credit risk, among other risks associated with derivative instruments. A buyer generally also will lose its investment and recover nothing should no credit event occur and the swap is held to its termination date. If a credit event were to occur, the value of any deliverable obligation received by the

seller, coupled with the upfront or periodic payments previously received, may be less than the full notional value it pays to the buyer, resulting in a loss of value to the seller. The Fund's obligations under a credit default swap will be accrued daily (offset against any amounts owing to the Fund). In connection with credit default swaps in which the Fund is the buyer, the Fund may segregate or "earmark" cash or liquid assets, or enter into certain offsetting positions, with a value at least equal to the Fund's exposure (any accrued but unpaid net amounts owed by the Fund to any counterparty), on a marked-to-market basis. In connection with credit default swaps in which the Fund is the seller, if the Fund covers its position through asset segregation, the Fund will segregate or "earmark" cash or liquid assets with a value at least equal to the full notional amount of the Fund's obligation under the swap. Such segregation or "earmarking" will not limit the Fund's exposure to loss. See "Principal Risks of the Fund—Segregation and Coverage Risk" and "Principal Risks of the Fund—Regulatory Risk— Commodity Pool Operator."

The Investment Manager currently considers credit default swaps to be illiquid and treats the market value of the contract as illiquid for purposes of determining compliance with the 20% restriction on illiquid investments.

Commercial paper represents short-term unsecured promissory notes issued in bearer form by corporations such as banks or bank holding companies and finance companies. The rate of return on commercial paper may be linked or indexed to the level of exchange rates between the U.S. dollar and a foreign currency or currencies.

Preferred securities represent an equity interest in a company that generally entitles the holder to receive, in preference to the holders of other stocks such as common stocks, dividends and a fixed share of the proceeds resulting from liquidation of the company. Unlike common stocks, preferred securities usually do not have voting rights. Preferred securities in some instances are convertible into common stock. Some preferred securities also entitle their holders to receive additional liquidation proceeds on the same basis as holders of a company's common stock, and thus also represent an ownership interest in the company. Some preferred securities offer a fixed rate of return with no maturity date. Because they never mature, these preferred securities may act like long-term bonds, can be more volatile than other types of preferred securities and may have heightened sensitivity to changes in interest rates. Other preferred securities have a variable dividend, generally determined on a quarterly or other periodic basis, either according to a formula based upon a specified premium or discount to the yield on particular U.S. Treasury securities or based on an auction process, involving bids submitted by holders and prospective purchasers of such securities. Although they are equity securities, preferred securities have certain characteristics of both debt securities and common stock. They are like debt securities in that their stated income is generally contractually fixed. They are like common stocks in that they do not have rights to precipitate bankruptcy proceedings or collection activities in the event of missed payments. Furthermore, preferred securities have many of the key characteristics of equity due to their subordinated position in an issuer's capital structure and because their quality and value are heavily dependent on the profitability of the issuer rather than on any legal claims to specific assets or cash flows. Because preferred securities represent an equity ownership interest in a company, their value usually will react more strongly than bonds and other debt instruments to actual or perceived changes in a company's financial condition or prospects, or to fluctuations in the equity markets.

In order to be payable, dividends on preferred securities must be declared by the issuer's board of directors. In addition, distributions on preferred securities may be subject to deferral and thus may not be automatically payable. Income payments on some preferred securities are cumulative, causing dividends and distributions to accrue even if they are not declared by the board of directors of the issuer or otherwise made payable. Other preferred securities are non-cumulative, meaning that skipped dividends and distributions do not continue to accrue. There is no assurance that dividends on preferred securities in which the Fund invests will be declared or otherwise made payable.

Preferred securities have a liquidation value that generally equals their original purchase price at the date of issuance. The market values of preferred securities may be affected by favorable and unfavorable changes affecting the issuers' industries or sectors. They also may be affected by actual and anticipated changes or ambiguities in the tax status of the security and by actual and anticipated changes or ambiguities in tax laws, such as changes in corporate and individual income tax rates or the rates applicable to dividends. The dividends paid on the preferred securities in which the Fund invests might not be eligible for the favorable tax treatment accorded to "qualified dividend income.". See "Taxation" in the Statement of Additional Information. Because the claim on an issuer's earnings represented by preferred securities may become disproportionately large when interest rates fall below the rate payable on the securities or for other reasons, the issuer may redeem preferred securities, generally after an initial period of call protection in which the security is not redeemable. Thus, in declining interest rate environments in particular, the Fund's holdings of higher dividend-paying preferred securities may be reduced and the Fund may be unable to acquire securities paying comparable rates with the redemption proceeds.

Convertible securities (i.e., debt securities that may be converted at either a stated price or stated rate into underlying shares of common stock) have general characteristics similar to both debt securities and equity securities. Although to a lesser extent than with debt obligations, the market value of convertible securities tends to decline as interest rates increase and, conversely, tends to increase as interest rates decline. In addition, because of the conversion feature, the market value of convertible securities tends to vary with fluctuations in the market value of the underlying common stocks and, therefore, also will react to variations in the general market for equity securities.

Convertible securities are investments that provide for a stable stream of income with generally higher yields than common stocks. There can be no assurance of current income because the issuers of the convertible securities may default on their obligations. Convertible securities, however, generally offer lower interest or dividend yields than non-convertible debt

securities of similar credit quality because of the potential for equity-related capital appreciation. A convertible security, in addition to providing current income, offers the potential for capital appreciation through the conversion feature, which enables the holder to benefit from increases in the market price of the underlying common stock.

The Fund may invest in synthetic convertible securities, which are created through a combination of separate securities that possess the two principal characteristics of a traditional convertible security, that is, an income-producing component and the right to acquire a convertible component. The income-producing component is achieved by investing in non-convertible, income-producing securities such as bonds, preferred securities and money market instruments. The convertible component is achieved by purchasing warrants or options to buy common stock at a certain exercise price, or options on a stock index. The Fund may also purchase synthetic securities created by other parties, typically investment banks, including convertible structured notes. The income-producing and convertible components of a synthetic convertible security may be issued separately by different issuers and at different times. The values of synthetic convertible securities will respond differently to market fluctuations than a traditional convertible security because a synthetic convertible is composed of two or more separate securities or instruments, each with its own market value. Synthetic convertible securities are also subject to the risks associated with derivatives. See "Principal Risks of the Fund—Derivatives Risk." In addition, if the value of the underlying common stock or the level of the index involved in the convertible element falls below the strike price of the warrant or option, the warrant or option may lose all value.

Contingent convertible securities ("CoCos") are a form of hybrid debt security issued primarily by non-U.S. issuers, which have loss absorption mechanisms built into their terms. CoCos have no stated maturity, have fully discretionary coupons and are typically issued in the form of subordinated debt instruments. CoCos generally either convert into equity of the issuer or have their principal written down upon the occurrence of certain triggering events ("triggers") linked to regulatory capital thresholds or regulatory actions relating to the issuer's continued viability. In certain scenarios, investors in CoCos may suffer a loss of capital ahead of equity holders or when equity holders do not. There is no guarantee that the Fund will receive a return of principal on CoCos. Any indication that an automatic write-down or conversion event may occur can be expected to have an adverse effect on the market price of CoCos. CoCos are often rated below investment grade and are subject to the risks of high yield securities.

Because CoCos are issued primarily by financial institutions, CoCos may present substantially increased risks at times of financial turmoil, which could affect financial institutions more than companies in other sectors and industries. Further, the value of an investment in CoCos is unpredictable and will be influenced by many factors and risks, including interest rate risk, credit risk, market risk and liquidity risk. An investment by the Fund in CoCos may result in losses to the Fund.

Loss absorption risk. CoCos may be subject to an automatic write-down (i.e., the automatic write-down of the principal amount or value of the securities, potentially to zero, and the cancellation of the securities) under certain circumstances, which could result in the Fund losing a portion or all of its investment in such securities. In addition, the Fund may not have any rights with respect to repayment of the principal amount of the securities that has not become due or the payment of interest or dividends on such securities for any period from (and including) the interest or dividend payment date falling immediately prior to the occurrence of such automatic write-down. An automatic write-down could also result in a reduced income rate if the dividend or interest payment is based on the security's par value. In addition, CoCos have fully discretionary coupons. This means coupons can potentially be cancelled at the issuer's discretion or at the request of the relevant regulatory authority in order to help the issuer absorb losses and may be suspended in the event there are insufficient distributable reserves.

Subordinated instruments. CoCos will, in the majority of circumstances, be issued in the form of subordinated debt instruments in order to provide the appropriate regulatory capital treatment prior to a conversion. Accordingly, in the event of liquidation, dissolution or winding-up of an issuer prior to a conversion having occurred, the rights and claims of the holders of the CoCos, such as the Funds, against the issuer in respect of or arising under the terms of the CoCos shall generally rank junior to the claims of all holders of unsubordinated obligations of the issuer. In addition, if the CoCos are converted into the issuer's underlying equity securities following a conversion event (i.e., a "trigger"), each holder will be subordinated due to their conversion from being the holder of a debt instrument to being the holder of an equity instrument.

Market value will fluctuate based on unpredictable factors. The trading behavior of a given issuer's CoCos may be strongly impacted by the trading behavior of other issuers' CoCos, such that negative information from an unrelated CoCo may cause a decline in value of one or more CoCos held by the Fund. Accordingly, the trading behavior of CoCos may not follow the trading behavior of other similarly structured securities. The value of CoCos is unpredictable and could be influenced by many factors including, without limitation: (i) the creditworthiness of the issuer and/or fluctuations in such issuer's applicable capital ratios; (ii) supply and demand for the CoCos; (iii) general market conditions and available liquidity; and (iv) economic, financial and political events that affect the issuer, its particular market or the financial markets in general.

The Fund may also invest in other bank obligations including without limitation certificates of deposit, bankers' acceptances and fixed time deposits. Certificates of deposit are negotiable certificates that are issued against funds deposited in a commercial bank for a definite period of time and that earn a specified return. Bankers' acceptances are negotiable drafts or bills of exchange, normally drawn by an importer or exporter to pay for specific merchandise, which are "accepted" by a bank, meaning, in effect, that the bank unconditionally agrees to pay the face value of the instrument on maturity. Fixed time deposits are bank obligations payable at a stated maturity date and bearing interest at a fixed rate. Fixed time deposits may be withdrawn on demand by the investor, but may be subject to early withdrawal penalties which vary depending upon market conditions and the remaining maturity of the obligation. There are generally no contractual restrictions on the right to transfer a beneficial interest in a fixed time deposit to a third party, although there is generally no market for such deposits. The Fund may also hold funds on deposit with its custodian bank in an interest-bearing account for temporary purposes.

The Fund may purchase indebtedness and participations in commercial loans, as well as interests and/or servicing or similar rights in such loans. Such investments may be secured or unsecured and may be newly-originated (and may be specifically designed for the Fund). Indebtedness is different from traditional debt securities in that debt securities are part of a large issue of securities to the public and indebtedness may not be a security, but may represent a specific commercial loan to a borrower. Loan participations typically represent direct participation, together with other parties, in a loan to a corporate borrower, and generally are offered by banks or other financial institutions or lending syndicates. The Fund may participate in such syndications, or can buy part of a loan, becoming a part lender. When purchasing indebtedness and loan participations, the Fund assumes the credit risk associated with the corporate borrower and may assume the credit risk associated with an interposed bank or other financial intermediary. The indebtedness and loan participations in which the Fund intends to invest may not be rated by any nationally recognized rating service.

A loan is often administered by an agent bank acting as agent for all holders. The agent bank administers the terms of the loan, as specified in the loan agreement. In addition, the agent bank is normally responsible for the collection of principal and interest payments from the corporate borrower and the apportionment of these payments to the credit of all institutions which are parties to the loan agreement. Unless, under the terms of the loan or other indebtedness, the Fund has direct recourse against the corporate borrower, the Fund may have to rely on the agent bank or other financial intermediary to apply appropriate credit remedies against a corporate borrower.

A financial institution's employment as agent bank might be terminated in the event that it fails to observe a requisite standard of care or becomes insolvent. A successor agent bank would generally be appointed to replace the terminated agent bank, and assets held by the agent bank under the loan agreement would likely remain available to holders of such indebtedness. However, if assets held by the agent bank for the benefit of the Fund were determined to be subject to the claims of the agent bank's general creditors, the Fund might incur certain costs and delays in realizing payment on a loan or loan participation and could suffer a loss of principal and/or interest. In situations involving other interposed financial institutions (e.g., an insurance company or governmental agency) similar risks may arise.

Purchasers of loans and other forms of direct indebtedness depend primarily upon the creditworthiness of the corporate borrower for payment of principal and interest. If the Fund does not receive scheduled interest or principal payments on such indebtedness, the NAV, market share price and/or yield of the Common Shares could be adversely affected. Loans that are fully secured offer the Fund more protection than an unsecured loan in the event of non-payment of scheduled interest or principal. However, there is no assurance that the liquidation of collateral from a secured loan would satisfy the corporate borrower's obligation, or that the collateral can be liquidated. In the event of the bankruptcy of a borrower, the Fund could experience delays or limitations in its ability to realize the benefits of any collateral securing a loan.

The Fund may invest in loan participations with credit quality comparable to that of issuers of its securities investments. Indebtedness of companies whose creditworthiness is poor involves substantially greater risks, and may be highly speculative. Some companies may never pay off their indebtedness, or may pay only a small fraction of the amount owed. Consequently, when investing in indebtedness of companies with poor credit, the Fund bears a substantial risk of losing the entire amount invested. The Fund may make investments in indebtedness and loan participations to achieve capital appreciation, rather than to seek income.

The Fund will limit the amount of its total assets that it will invest in any one issuer and the Fund will limit the amount of its total assets that it will invest in issuers within the same industry. For purposes of this limit, the Fund generally will treat the corporate borrower as the "issuer" of indebtedness held by the Fund. In the case of loan participations where a bank or other lending institution serves as a financial intermediary between the Fund and the corporate borrower, if the participation does not shift to the Fund the direct debtor-creditor relationship with the corporate borrower, the Fund will treat both the lending bank or other lending institution and the corporate borrower as "issuers." Treating a financial intermediary as an issuer of indebtedness may restrict the Fund's ability to invest in indebtedness related to a single financial intermediary, or a group of intermediaries engaged in the same industry, even if the underlying borrowers represent many different companies and industries.

financial institutions and accordingly may be deemed liquid. As the market for different types of indebtedness develops, the liquidity of these instruments is expected to improve. Investments in loan participations are considered to be debt obligations for purposes of the Trust's investment restriction relating to the lending of funds or assets by the Fund.

Investments in loans through a purchase of a loan or direct assignment of a financial institution's interests with respect to a loan may involve additional risks to the Fund. The purchaser of an assignment typically succeeds to all the rights and obligations under the loan agreement with the same rights and obligations as the assigning lender. Assignments may, however, be arranged through private negotiations between potential assignees and potential assignors, and the rights and obligations acquired by the purchaser of an assignment may differ from, and be more limited than, those held by the assigning lender. If a loan is foreclosed, the Fund could become part owner of any collateral, and would bear the costs and liabilities associated with owning and disposing of the collateral. In addition, it is conceivable that under emerging legal theories of lender liability, the Fund could be held liable as co-lender. It is unclear whether loans and other forms of direct indebtedness offer securities law protections against fraud and misrepresentation. In the absence of definitive regulatory guidance, the Fund relies on PIMCO's research in an attempt to avoid situations where fraud or misrepresentation could adversely affect the Fund.

The Fund may invest in debtor-in-possession financings (commonly known as "DIP financings"). DIP financings are arranged when an entity seeks the protections of the bankruptcy court under Chapter 11 of the U.S. Bankruptcy Code. These financings allow the entity to continue its business operations while reorganizing under Chapter 11. Such financings constitute senior liens on unencumbered security (i.e., security not subject to other creditors' claims). There is a risk that the entity will not emerge from Chapter 11 and be forced to liquidate its assets under Chapter 7 of the U.S. Bankruptcy Code. In the event of liquidation, the Fund's only recourse will be against the property securing the DIP financing.

Various state licensing requirements could apply to the Fund with respect to investments in loans and similar assets. The licensing requirements could apply depending on the location of the borrower, the location of the collateral securing the loan, or the location where the Fund or PIMCO operates or has offices. In states in which it is licensed, the Fund or PIMCO will be required to comply with applicable laws and regulations, including consumer protection and anti-fraud laws, which could impose restrictions on the Fund's or PIMCO's ability to take certain actions to protect the value of its investments in such assets and impose compliance costs. Failure to comply with such laws and regulations could lead to, among other penalties, a loss of the Fund's or PIMCO's license, which in turn could require the Fund to divest assets located in or secured by real property located in that state. These risks will also apply to issuers and entities in which the Fund invests that hold similar assets, as well as any origination company or servicer in which the Fund owns an interest.

Loan origination and servicing companies are routinely involved in legal proceedings concerning matters that arise in the ordinary course of their business. These legal proceedings range from actions involving a single plaintiff to class action lawsuits with potentially tens of thousands of class members. In addition, a number of participants in the loan origination and servicing industry (including control persons of industry participants) have been the subject of regulatory actions by state regulators, including state Attorneys General, and by the federal government. Governmental investigations, examinations or regulatory actions, or private lawsuits, including purported class action lawsuits, may adversely affect such companies' financial results. To the extent the Fund seeks to engage in servicing directly, or has a financial interest in, or is otherwise affiliated with, an origination or servicing company, the Fund will be subject to enhanced risks of litigation, regulatory actions and other proceedings. As a result, the Fund may be required to pay legal fees, settlement costs, damages, penalties or other charges, any or all of which could materially adversely affect the Fund and its investments.

Zero-coupon bonds pay interest only at maturity rather than at intervals during the life of the security. Like zero-coupon bonds, "step up" bonds pay no interest initially but eventually begin to pay a coupon rate prior to maturity, which rate may increase at stated intervals during the life of the security. Payment-in-kind securities ("PIKs") are debt obligations that pay "interest" in the form of other debt obligations, instead of in cash. Each of these instruments is normally issued and traded at a deep discount from face value. Zero-coupon bonds, step-ups and PIKs allow an issuer to avoid or delay the need to generate cash to meet current interest payments and, as a result, may involve greater credit risk than bonds that pay interest currently or in cash. The Fund would be required to distribute the income on these instruments as it accrues, even though the Fund will not receive the income on a current basis or in cash. Thus, the Fund may have to sell investments, including when it may not be advisable to do so, to make income distributions to its shareholders.

The Fund may invest some or all of its assets in U.S. dollar-denominated debt obligations of foreign corporate issuers and of supra-national government entities. Supra-national entities include international organizations that are organized or supported by one or more government entities to promote economic reconstruction or development and by international banking institutions and related governmental agencies. The Fund also may invest up to 25% of its total assets in non-U.S. dollar denominated securities (of both developed and "emerging market" countries), including obligations of non-U.S. governments and their respective sub-divisions, agencies and government-sponsored enterprises. Investing in foreign securities involves special risks and considerations not typically associated with investing in U.S. securities. See "Principal Risks of the Fund—Foreign (Non-U.S.) Investment Risk."

PIMCO generally considers an instrument to be economically tied to a non-U.S. country if the issuer is a foreign (non-U.S.) government (or any political subdivision, agency, authority or instrumentality of such government), or if the issuer is organized under the laws of a non-U.S. country. In the case of certain money market instruments, such instruments will be considered economically tied to a non-U.S. country if either the issuer or the guarantor of such money market instrument is organized under the laws of a non-U.S. country. With respect to derivative instruments, PIMCO generally considers such instruments to be economically tied to non-U.S. countries if the

underlying assets are foreign currencies (or baskets or indexes of such currencies), or instruments or securities that are issued by foreign governments or issuers organized under the laws of a non-U.S. country (or if the underlying assets are certain money market instruments, if either the issuer or the guarantor of such money market instruments is organized under the laws of a non-U.S. country).

The Fund may invest in Brady Bonds, which are securities created through the exchange of existing commercial bank loans to sovereign entities for new obligations in connection with a debt restructuring. Investments in Brady Bonds may be viewed as speculative. Brady Bonds acquired by the Fund may be subject to restructuring arrangements or to requests for new credit, which may cause the Fund to realize a loss of interest or principal on any of its portfolio holdings.

The foreign securities in which the Fund may invest include without limit Eurodollar obligations and "Yankee Dollar" obligations. Eurodollar obligations are U.S. dollar-denominated certificates of deposit and time deposits issued outside the U.S. capital markets by foreign branches of U.S. banks and by foreign banks. Yankee Dollar obligations are U.S. dollar-denominated obligations issued in the U.S. capital markets by foreign banks. Eurodollar and Yankee Dollar obligations are generally subject to the same risks that apply to domestic debt issues, notably credit risk, interest rate risk, market risk and liquidity risk. Additionally, Eurodollar (and to a limited extent, Yankee Dollar) obligations are subject to certain sovereign risks. One such risk is the possibility that a sovereign country might prevent capital, in the form of U.S. dollars, from flowing across its borders. Other risks include adverse political and economic developments; the extent and quality of government regulation of financial markets and institutions; the imposition of foreign withholding or other taxes; and the expropriation or nationalization of foreign issuers.

The Fund may invest without limit in short-term investment grade sovereign debt, including short-term investment grade sovereign debt issued by emerging market issuers. The Fund may invest up to 40% of its total assets in securities and instruments that are economically tied to "emerging market" countries other than investments in short-term investment grade sovereign debt issued by emerging market issuers, where as noted above there is no limit. PIMCO generally considers an instrument to be economically tied to an emerging market country if: the issuer is organized under the laws of an emerging market country; the currency of settlement of the security is a currency of an emerging market country; the security is guaranteed by the government of an emerging market country (or any political subdivision, agency, authority or instrumentality of such government); for an asset-backed or other collateralized security, the country in which the collateral backing the security is located is an emerging market country; or the security's "country of exposure" is an emerging market country, as determined by the criteria set forth below. With respect to derivative instruments, PIMCO generally considers such instruments to be economically tied to emerging market countries if the underlying assets are currencies of emerging market countries (or baskets or indexes of such currencies), or instruments or securities that are issued or guaranteed by governments of emerging market countries or by entities organized under the laws of emerging market countries or an instrument's "country of exposure" is an emerging market country. A security's "country of exposure" is determined by PIMCO using certain factors provided by a third-party analytical service provider. The factors are applied in order such that the first factor to result in the assignment of a country determines the "country of exposure." The factors, listed in the order in which they are applied, are: (i) if an asset-backed or other collateralized security, the country in which the collateral backing the security is located; (ii) the "country of risk" of the issuer; (iii) if the security is guaranteed by the government of a country (or any political subdivision, agency, authority or instrumentality of such government), the country of the government or instrumentality providing the guarantee; (iv) the "country of risk" of the issuer's ultimate parent, or (v) the country where the issuer is organized or incorporated under the laws thereof. "Country of risk" is a separate four-part test determined by the following factors, listed in order of importance: (i) management location, (ii) country of primary listing, (iii) sales or revenue attributable to the country, and (iv) reporting currency of the issuer. PIMCO has broad discretion to identify countries that it considers to qualify as emerging markets. Emerging market countries are generally located in Asia, Africa, the Middle East, Latin America and Eastern Europe but may be in other regions as well. PIMCO will consider emerging market country and currency composition based on its evaluation of relative interest rates, inflation rates, exchange rates, monetary and fiscal policies, trade and current account balances, legal and political developments and any other specific factors it believes to be relevant.

The securities and currency markets of emerging market countries are generally smaller, less developed, less liquid, and more volatile than the securities and currency markets of the United States and other developed markets and disclosure and regulatory standards in many respects are less stringent. There also may be a lower level of monitoring and regulation of securities markets in emerging market countries and the activities of investors in such markets and enforcement of existing regulations may be extremely limited. Government enforcement of existing securities regulations is limited, and any enforcement may be arbitrary and the results may be difficult to predict. In addition, reporting requirements of emerging market countries with respect to the ownership of securities are more likely to be subject to interpretation or changes without prior notice to investors than more developed countries.

Many emerging market countries have experienced substantial, and in some periods extremely high, rates of inflation for many years. Inflation and rapid fluctuations in inflation rates have had and may continue to have negative effects on such countries' economies and securities markets.

Economies of emerging market countries generally are heavily dependent upon international trade and, accordingly, have been and may continue to be affected adversely by trade barriers, exchange controls, managed adjustments in relative currency values, and other protectionist measures imposed or negotiated by the countries with which they trade. The economies of emerging market countries also have been and may continue to be adversely affected by economic conditions in the countries with which they trade. The economies of emerging market countries may also be predominantly based on only a few industries or dependent on revenues from particular commodities. In addition, custodial services and other

investment-related costs may be more expensive in emerging markets than in many developed markets, which could reduce the Fund's income from securities or debt instruments of emerging market country issuers.

Governments of many emerging market countries have exercised and continue to exercise substantial influence over many aspects of the private sector. In some cases, the government owns or controls many companies, including some of the largest in the country. Accordingly, government actions could have a significant effect on economic conditions in an emerging country and on market conditions, prices and yields of securities in the Fund's portfolio.

Emerging market countries are more likely than developed market countries to experience political uncertainty and instability, including the risk of war, terrorism, nationalization, limitations on the removal of funds or other assets, or diplomatic developments that affect investments in these countries. No assurance can be given that adverse political changes will not cause the Fund to suffer a loss of any or all of its investments in emerging market countries or interest/dividend income thereon.

Foreign investment in certain emerging market country securities is restricted or controlled to varying degrees. These restrictions or controls may at times limit or preclude foreign investment in certain emerging market country securities and increase the costs and expenses of the Fund. Certain emerging market countries require governmental approval prior to investments by foreign persons, limit the amount of investment by foreign persons in a particular issuer, limit the investment by foreign persons only to a specific class of securities of an issuer that may have less advantageous rights than the classes available for purchase by domiciliaries of the countries and/or impose additional taxes on foreign investors. Certain emerging market countries may also restrict investment opportunities in issuers in industries deemed important to national interests. Emerging market countries may require governmental approval for the repatriation of investment income, capital or the proceeds of sales of securities by foreign investors.

Also, because publicly traded debt instruments of emerging market issuers represent a relatively recent innovation in the world debt markets, there is little historical data or related market experience concerning the attributes of such instruments under all economic, market and political conditions.

As reflected in the above discussion, investments in emerging market securities involve a greater degree of risk than, and special risks in addition to the risks associated with, investments in domestic securities or in securities of foreign developed countries. See "Principal Risks of the Fund—Emerging Markets Risk."

The Fund's Common Shares are priced in U.S. dollars and the distributions paid by the Fund to Common Shareholders are paid in U.S. dollars. However, a significant portion of the Fund's assets may be denominated in foreign (non-U.S.) currencies and the income received by the Fund from many foreign debt obligations will be paid in foreign currencies. The Fund also may invest in or gain exposure to foreign currencies themselves for investment or hedging purposes. The Fund's investments in securities that trade in, or receive revenues in, foreign currencies will be subject to currency risk, which is the risk that fluctuations in the exchange rates between the U.S. dollar and foreign currencies may negatively affect an investment. See "Principal Risks of the Fund—Currency Risk." The Fund may (but is not required to) hedge some or all of its exposure to foreign currencies through the use of derivative strategies. For instance, the Fund may enter into forward foreign currency exchange contracts, and may buy and sell foreign currency futures contracts and options on foreign currencies and foreign currency futures. A forward foreign currency exchange contract, which involves an obligation to purchase or sell a specific currency at a future date at a price set at the time of the contract, may reduce the Fund's exposure to changes in the value of the currency it will deliver and increase its exposure to changes in the value of the currency it will receive for the duration of the contract. The effect on the value of the Fund is similar to selling securities denominated in one currency and purchasing securities denominated in another currency. Foreign currency transactions, like currency exchange rates, can be affected unpredictably by intervention (or the failure to intervene) by U.S. or foreign governments or central banks, or by currency controls or political developments. Such events may prevent or restrict the Fund's ability to enter into foreign currency transactions, force the Fund to exit a foreign currency transaction at a disadvantageous time or price or result in penalties for the Fund, any of which may result in a loss to the Fund. Contracts to sell foreign currency would limit any potential gain that might be realized by the Fund if the value of the hedged currency increases. The Fund may enter into these contracts to hedge against foreign exchange risk arising from the Fund's investment or anticipated investment in securities denominated in foreign currencies. Suitable hedging transactions may not be available in all circumstances and there can be no assurance that the Fund will engage in such transactions at any given time or from time to time when they would be beneficial. Although PIMCO has the flexibility to engage in such transactions for the Fund, it may determine not to do so or to do so only in unusual circumstances or market conditions. Also, these transactions may not be successful and may eliminate any chance for the Fund to benefit from favorable fluctuations in relevant foreign currencies.

The Fund may also use derivatives contracts for purposes of increasing exposure to a foreign currency or to shift exposure to foreign currency fluctuations from one currency to another. To the extent that it does so, the Fund will be subject to the additional risk that the relative value of currencies will be different than anticipated by PIMCO.

Please see "Investment Objective and Policies—Non-U.S. Securities," "Investment Objective and Policies— Foreign Currency Transactions" and "Investment Objective and Policies—Foreign Currency Exchange-Related Securities" in the Statement of Additional Information for a more detailed description of the types of foreign investments and foreign currency transactions in which the Fund may invest or engage and their related risks.

The Fund may, but is not required to, utilize a variety of derivative strategies (both long and short positions) for investment purposes, leveraging purposes, or in an attempt to hedge against market, credit, interest rate, currency and other risks in the portfolio. See "Use of Leverage." Generally, derivatives are financial contracts whose value depends upon, or is derived

from, the value of an underlying asset, reference rate or index, and may relate to, among others, individual debt instruments, interest rates, currencies or currency exchange rates, commodities, and related indexes. Examples of derivative instruments that the Fund may use include, without limit, futures and forward contracts (including foreign currency exchange contracts), call and put options (including options on futures contracts), credit default swaps, total return swaps, basis swaps and other swap agreements. The Fund's use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investment directly in securities and other more traditional investments. See "Principal Risks of the Fund— Derivatives Risk." Certain types of derivative instruments that the Fund may utilize are described elsewhere in this section, including those described under "—Certain Interest Rate Transactions," "—Hybrid Instruments," "—Structured Notes and Related Instruments" and "— Credit Default Swaps." Please see "Investment Objective and Policies— Derivative Instruments" in the Statement of Additional Information for additional information about these and other derivative instruments that the Fund may use and the risks associated with such instruments. There is no assurance that these derivative strategies will be available at any time or that PIMCO will determine to use them for the Fund or, if used, that the strategies will be successful. In addition, the Fund is subject to certain restrictions on its use of derivative strategies imposed by guidelines of Moody's, which issues ratings for ARPS.

The Fund may invest in a variety of mortgage-related and other asset-backed securities issued by government agencies or other governmental entities or by private originators or issuers.

Mortgage-related securities include mortgage pass-through securities, CMOs, commercial mortgage-backed securities ("CMBSs"), mortgage dollar rolls, CMO residuals, adjustable rate mortgage-backed securities ("ARMs"), SMBSs and other securities that directly or indirectly represent a participation in, or are secured by and payable from, mortgage loans on real property.

Mortgage Pass-Through Securities. Interests in pools of mortgage-related securities differ from other forms of debt securities, which normally provide for periodic payment of interest in fixed amounts with principal payments at maturity or specified call dates. Instead, these securities provide a monthly payment which consists of both interest and principal payments. In effect, these payments are a "pass through" of the monthly payments made by the individual borrowers on their residential or commercial mortgage loans, net of any fees paid to the issuer or guarantor of such securities. Additional payments are caused by repayments of principal resulting from the sale of the underlying property, refinancing or foreclosure, net of fees or costs that may be incurred. Some mortgage-related securities (such as securities issued by GNMA) are described as "modified pass-through." These securities entitle the holder to receive all interest and principal payments owed on the mortgage pool, net of certain fees, at the scheduled payment dates regardless of whether or not the mortgagor actually makes the payment.

The rate of pre-payments on underlying mortgages will affect the price and volatility of a mortgage-related security, and may have the effect of shortening or extending the effective duration of the security relative to what was anticipated at the time of purchase. To the extent that unanticipated rates of prepayment on underlying mortgages increase the effective duration of a mortgage-related security, the volatility of such security can be expected to increase. The mortgage market in the United States has experienced heightened difficulties over the past several years that may adversely affect the performance and market value of mortgage-related investments. Delinquencies and losses on residential and commercial mortgage loans (especially subprime and second-lien residential mortgage loans) generally have increased recently and may continue to increase, and a decline in or flattening of property values (as has recently been experienced and may continue to be experienced in many markets) may exacerbate such delinquencies and losses. Borrowers with adjustable-rate mortgage loans are more sensitive to changes in interest rates, which affect their monthly mortgage payments, and may be unable to secure replacement mortgages at comparably low interest rates. Also, a number of residential mortgage loan originators have recently experienced serious financial difficulties or bankruptcy. Owing largely to the foregoing, reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen.

The principal U.S. governmental guarantor of mortgage-related securities is GNMA. GNMA is a wholly owned U.S. Government corporation within the Department of Housing and Urban Development. GNMA 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 (such as savings and loan institutions, commercial banks and mortgage bankers) and backed by pools of mortgages insured by the Federal Housing Administration (the "FHA"), or guaranteed by the Department of Veterans Affairs (the "VA"). Government-related guarantors (i.e., not backed by the full faith and credit of the U.S. Government) include FNMA and FHLMC. FNMA is a government-sponsored corporation the common stock of which is owned entirely by private stockholders. FNMA purchases conventional (i.e., not insured or guaranteed by any government agency) residential mortgages from a list of approved seller/servicers which include state and federally chartered savings and loan associations, mutual savings banks, commercial banks and credit unions and mortgage bankers. Pass-through securities issued by FNMA are guaranteed as to timely payment of principal and interest by FNMA, but are not backed by the full faith and credit of the U.S. Government. FHLMC was created by Congress in 1970 for the purpose of increasing the availability of mortgage credit for residential housing. It is a government-sponsored corporation that issues Participation Certificates ("PCs"), which are pass-through securities, each representing an undivided interest in a pool of residential mortgages. FHLMC guarantees the timely payment of interest and ultimate collection of principal, but PCs are not backed by the full faith and credit of the U.S. Government.

On September 6, 2008, the Federal Housing Finance Agency ("FHFA") placed FNMA and FHLMC into conservatorship. As the conservator, FHFA succeeded to all rights, titles, powers and privileges of FNMA and FHLMC

and of any stockholder, officer or director of FNMA and FHLMC with respect to FNMA and FHLMC and the assets of FNMA and FHLMC. FHFA selected a new chief executive officer and chairman of the board of directors for each of FNMA and FHLMC. In connection with the conservatorship, the U.S. Treasury entered into a Senior Preferred Stock Purchase Agreement with each of FNMA and FHLMC pursuant to which the U.S. Treasury will purchase up to an aggregate of $100 billion of each of FNMA and FHLMC to maintain a positive net worth in each enterprise. This agreement contains various covenants that severely limit each enterprise's operations. In exchange for entering into these agreements, the U.S. Treasury received $1 billion of each enterprise's senior preferred stock and warrants to purchase 79.9% of each enterprise's common stock. On February 18, 2009, the U.S. Treasury announced that it was doubling the size of its commitment to each enterprise under the Senior Preferred Stock Program to $200 billion. The U.S. Treasury's obligations under the Senior Preferred Stock Program are for an indefinite period of time for a maximum amount of $200 billion per enterprise. On December 24, 2009, the U.S. Treasury announced further amendments to the Senior Preferred Stock Purchase Agreements which included additional financial support to certain governmentally supported entities, including the FHLBs, FNMA and FHLMC. There is no assurance that the obligations of such entities will be satisfied in full, or that such obligations will not decrease in value or default. It is difficult, if not impossible, to predict the future political, regulatory or economic changes that could impact the FNMA, FHLMC and the FHLBs, and the values of their related securities or obligations.

FNMA and FHLMC are continuing to operate as going concerns while in conservatorship and each remain liable for all of its obligations, including its guaranty obligations, associated with its mortgage-backed securities.

Under the Federal Housing Finance Regulatory Reform Act of 2008 (the "Reform Act"), which was included as part of the Housing and Economic Recovery Act of 2008, FHFA, as conservator or receiver, has the power to repudiate any contract entered into by FNMA or FHLMC prior to FHFA's appointment as conservator or receiver, as applicable, if FHFA determines, in its sole discretion, that performance of the contract is burdensome and that repudiation of the contract promotes the orderly administration of FNMA's or FHLMC's affairs. The Reform Act requires FHFA to exercise its right to repudiate any contract within a reasonable period of time after its appointment as conservator or receiver. FHFA, in its capacity as conservator, has indicated that it has no intention to repudiate the guaranty obligations of FNMA or FHLMC because FHFA views repudiation as incompatible with the goals of the conservatorship. However, in the event that FHFA, as conservator or if it is later appointed as receiver for FNMA or FHLMC, were to repudiate any such guaranty obligation, the conservatorship or receivership estate, as applicable, would be liable for actual direct compensatory damages in accordance with the provisions of the Reform Act. Any such liability could be satisfied only to the extent of FNMA's or FHLMC's assets available therefor. In the event of repudiation, the payments of interest to holders of FNMA or FHLMC mortgage-backed securities would be reduced if payments on the mortgage loans represented in the mortgage loan groups related to such mortgage-backed securities are not made by the borrowers or advanced by the servicer. Any actual direct compensatory damages for repudiating these guaranty obligations may not be sufficient to offset any shortfalls experienced by such mortgage-backed security holders. Further, in its capacity as conservator or receiver, FHFA has the right to transfer or sell any asset or liability of FNMA or FHLMC without any approval, assignment or consent. Although FHFA has stated that it has no present intention to do so, if FHFA, as conservator or receiver, were to transfer any such guaranty obligation to another party, holders of FNMA or FHLMC mortgage-backed securities would have to rely on that party for satisfaction of the guaranty obligation and would be exposed to the credit risk of that party. In addition, certain rights provided to holders of mortgage-backed securities issued by FNMA and FHLMC under the operative documents related to such securities may not be enforced against FHFA, or enforcement of such rights may be delayed, during the conservatorship or any future receivership. The operative documents for FNMA and FHLMC mortgage-backed securities may provide (or with respect to securities issued prior to the date of the appointment of the conservator may have provided) that upon the occurrence of an event of default on the part of FNMA or FHLMC, in its capacity as guarantor, which includes the appointment of a conservator or receiver, holders of such mortgage-backed securities have the right to replace FNMA or FHLMC as trustee if the requisite percentage of mortgage-backed securities holders consent. The Reform Act prevents mortgage-backed security holders from enforcing such rights if the event of default arises solely because a conservator or receiver has been appointed. The Reform Act also provides that no person may exercise any right or power to terminate, accelerate or declare an event of default under certain contracts to which FNMA or FHLMC is a party, or obtain possession of or exercise control over any property of FNMA or FHLMC, or affect any contractual rights of FNMA or FHLMC, without the approval of FHFA, as conservator or receiver, for a period of 45 or 90 days following the appointment of FHFA as conservator or receiver, respectively.

In addition, in a February 2011 report to Congress from the Treasury Department and the Department of Housing and Urban Development, the Obama administration provided a plan to reform America's housing finance market. The plan would reduce the role of and eventually eliminate FNMA and FHLMC. Notably, the plan does not propose similar significant changes to GNMA, which guarantees payments on mortgage-related securities backed by federally insured or guaranteed loans such as those issued by the Federal Housing Association or guaranteed by the VA. The report also identified three proposals for Congress and the administration to consider for the long-term structure of the housing finance markets after the elimination of FNMA and FHLMC, including implementing: (i) a privatized system of housing finance that limits government insurance to very limited groups of creditworthy low- and moderate-income borrowers; (ii) a privatized system with a government backstop mechanism that would allow the government to insure a larger share of the housing finance market during a future housing crisis; and (iii) a privatized system where the government would offer reinsurance to holders of certain highly-rated mortgage-related securities insured by private insurers and would pay out under the reinsurance arrangements only if the private mortgage insurers were insolvent.

Commercial banks, savings and loan institutions, private mortgage insurance companies, mortgage bankers and other secondary market

issuers also create pass-through pools of conventional residential mortgage loans. Such issuers may be the originators and/or servicers of the underlying mortgage loans as well as the guarantors of the mortgage-related securities. Pools created by such non-governmental issuers generally offer a higher rate of interest than government and government-related pools because there are no direct or indirect government or agency guarantees of payments in the former pools. However, timely payment of interest and principal of these pools may be supported by various forms of insurance or guarantees, including individual loan, title, pool and hazard insurance and letters of credit, which may be issued by governmental entities or private insurers. Such insurance and guarantees and the creditworthiness of the issuers thereof will be considered in determining whether a mortgage-related security should be purchased for the Fund. There can be no assurance that the private insurers or guarantors can meet their obligations under the insurance policies or guarantee arrangements. The Fund may, however, invest in mortgage-related securities without insurance or guarantees if PIMCO believes that the securities will help to achieve the Fund's investment objective. Securities issued by certain private organizations may not be readily marketable.

Privately-Issued Mortgage-Related Securities. Commercial banks, savings and loan institutions, private mortgage insurance companies, mortgage bankers and other secondary market issuers also create pass-through pools of conventional residential mortgage loans. Such issuers may be the originators and/or servicers of the underlying mortgage loans as well as the guarantors of the mortgage-related securities. Pools created by such non-governmental issuers generally offer a higher rate of interest than government and government-related pools because there are no direct or indirect government or agency guarantees of payments in the former pools. However, timely payment of interest and principal of these pools may be supported by various forms of insurance or guarantees, including individual loan, title, pool and hazard insurance and letters of credit, which may be issued by governmental entities or private insurers. Such insurance and guarantees and the creditworthiness of the issuers thereof will be considered in determining whether a mortgage-related security meets the Fund's investment quality standards. There can be no assurance that insurers or guarantors can meet their obligations under the insurance policies or guarantee arrangements. The Fund may buy mortgage-related securities without insurance or guarantees if, through an examination of the loan experience and practices of the originators/servicers and poolers, PIMCO determines that the securities meet the Fund's quality standards. Securities issued by certain private organizations may not be readily marketable.

Privately-issued mortgage-related securities are not subject to the same underwriting requirements for the underlying mortgages that are applicable to those mortgage-related securities that have a government or government-sponsored entity guarantee. As a result, the mortgage loans underlying privately-issued mortgage-related securities may, and frequently do, have less favorable collateral, credit risk or other underwriting characteristics than government or government-sponsored mortgage-related securities and have wider variances in a number of terms including interest rate, term, size, purpose and borrower characteristics. Mortgage pools underlying privately-issued mortgage-related securities more frequently include second mortgages, high loan-to-value ratio mortgages and manufactured housing loans, in addition to commercial mortgages and other types of mortgages where a government or government-sponsored entity guarantee is not available. The coupon rates and maturities of the underlying mortgage loans in a privately-issued mortgage-related securities pool may vary to a greater extent than those included in a government guaranteed pool, and the pool may include subprime mortgage loans. Subprime loans are loans made to borrowers with weakened credit histories or with a lower capacity to make timely payments on their loans. For these reasons, the loans underlying these securities have had in many cases higher default rates than those loans that meet government underwriting requirements.

The risk of non-payment is greater for mortgage-related securities that are backed by loans that were originated under weak underwriting standards, including loans made to borrowers with limited means to make repayment. A level of risk exists for all loans, although, historically, the poorest performing loans have been those classified as subprime. Other types of privately-issued mortgage-related securities, such as those classified as pay-option adjustable rate or Alt-A have also performed poorly. Even loans classified as prime have experienced higher levels of delinquencies and defaults. The substantial decline in real property values across the U.S. has exacerbated the level of losses that investors in privately-issued mortgage-related securities have experienced. It is not certain when these trends may reverse. Market factors that may adversely affect mortgage loan repayment include adverse economic conditions, unemployment, a decline in the value of real property, or an increase in interest rates.

The Fund may purchase privately-issued mortgage-related securities that are originated, packaged and serviced by third party entities. It is possible these third parties could have interests that are in conflict with the holders of mortgage-related securities, and such holders (such as the Fund) could have rights against the third parties or their affiliates. For example, if a loan originator, servicer or its affiliates engaged in negligence or willful misconduct in carrying out its duties, then a holder of the mortgage-related security could seek recourse against the originator/servicer or its affiliates, as applicable. Also, as a loan originator/servicer, the originator/servicer or its affiliates may make certain representations and warranties regarding the quality of the mortgages and properties underlying a mortgage-related security. If one or more of those representations or warranties is false, then the holders of the mortgage-related securities (such as the Fund) could trigger an obligation of the originator/servicer or its affiliates, as applicable, to repurchase the mortgages from the issuing trust.

Notwithstanding the foregoing, many of the third parties that are legally bound by trust and other documents have failed to perform their respective duties, as stipulated in such trust and other documents, and investors have had limited success in enforcing terms. To the extent third party entities

involved with privately issued mortgage-related securities are involved in litigation relating to the securities, actions may be taken that are adverse to the interests of holders of the mortgage-related securities, including the Fund. For example, third parties may seek to withhold proceeds due to holders of the mortgage-related securities, including the Fund, to cover legal or related costs. Any such action could result in losses to the Fund.

PIMCO seeks to manage the portion of the Fund's assets committed to privately-issued mortgage-related securities in a manner consistent with the Fund's investment objective, policies and overall portfolio risk profile. In determining whether and how much to invest in privately-issued mortgage-related securities, and how to allocate those assets, PIMCO will consider a number of factors. These include, but are not limited to: (1) the nature of the borrowers (e.g., residential vs. commercial); (2) the collateral loan type (e.g., for residential: First Lien - Jumbo/Prime, First Lien - Alt-A, First Lien - Subprime, First Lien - Pay-Option or Second Lien; for commercial: Conduit, Large Loan or Single Asset / Single Borrower); and (3) in the case of residential loans, whether they are fixed rate or adjustable mortgages. Each of these criteria can cause privately-issued mortgage-related securities to have differing primary economic characteristics and distinguishable risk factors and performance characteristics.

Collateralized Mortgage Obligations. A CMO is a debt obligation of a legal entity that is collateralized by mortgages and divided into classes. Similar to a bond, interest and prepaid principal is paid, in most cases, on a monthly basis. CMOs may be collateralized by whole mortgage loans or private mortgage bonds, but are generally collateralized by portfolios of mortgage pass-through securities guaranteed by GNMA, FHLMC or FNMA and their income streams. CMOs are structured into multiple classes, often referred to as "tranches," with each class bearing a different stated maturity and entitled to a different schedule for payments of principal and interest, including prepayments. The riskiest portion is the "equity" tranche which bears the bulk of defaults and serves to protect the other, more senior tranches from default in all but the most severe circumstances. Actual maturity and average life will depend upon the pre-payment experience of the collateral. In the case of certain CMOs (known as "sequential pay" CMOs), payments of principal received from the pool of underlying mortgages, including prepayments, are applied to the classes of CMOs in the order of their respective final distribution dates. Thus, no payment of principal will be made to any class of sequential pay CMOs until all other classes having an earlier final distribution date have been paid in full. CMOs may be less liquid and may exhibit greater price volatility than other types of mortgage- or asset-backed securities.

Commercial Mortgage-Backed Securities. CMBSs include securities that reflect an interest in, and are secured by, mortgage loans on commercial real property. Many of the risks of investing in commercial mortgage-backed securities reflect the risks of investing in the real estate securing the underlying mortgage loans. These risks reflect the effects of local and other economic conditions on real estate markets, the ability of tenants to make loan payments and the ability of a property to attract and retain tenants. Commercial mortgage-backed securities may be less liquid and exhibit greater price volatility than other types of mortgage- or asset-backed securities.

CMO Residuals. CMO residuals are mortgage securities issued by agencies or instrumentalities of the U.S. Government or by private originators of, or investors in, mortgage loans, including savings and loan associations, homebuilders, mortgage banks, commercial banks, investment banks and special purpose entities of the foregoing. The cash flow generated by the mortgage assets underlying a series of a CMO is applied first to make required payments of principal and interest on the CMO and second to pay the related administrative expenses and any management fee of the issuer. The residual in a CMO structure generally represents the interest in any excess cash flow remaining after making the foregoing payments. Each payment of such excess cash flow to a holder of the related CMO residual represents income and/or a return of capital. The amount of residual cash flow resulting from a CMO will depend on, among other things, the characteristics of the mortgage assets, the coupon rate of each class of CMO, prevailing interest rates, the amount of administrative expenses and the prepayment experience on the mortgage assets. In particular, the yield to maturity on CMO residuals is extremely sensitive to prepayments on the related underlying mortgage assets, in the same manner as an interest-only (or IO) class of stripped mortgage-backed securities (described below). In addition, if a series of a CMO includes a class that bears interest at an adjustable rate, the yield to maturity on the related CMO residual will also be extremely sensitive to changes in the level of the index upon which interest rate adjustments are based. As described below with respect to stripped mortgage-backed securities, in certain circumstances the Fund may fail to recoup fully its initial investment in a CMO residual. CMO residuals are generally purchased and sold by institutional investors through several investment banking firms acting as brokers or dealers. CMO residuals may, or pursuant to an exemption therefrom, may not, have been registered under the 1933 Act. CMO residuals, whether or not registered under the 1933 Act, may be subject to certain restrictions on transferability.

Adjustable Rate Mortgage-Backed Securities. ARMs have interest rates that reset at periodic intervals. Acquiring ARMs permits the Fund to participate in increases in prevailing current interest rates through periodic adjustments in the coupons of mortgages underlying the pool on which ARMs are based. Such ARMs generally have higher current yield and lower price fluctuations than is the case with more traditional fixed income debt securities of comparable rating and maturity. In addition, when prepayments of principal are made on the underlying mortgages during periods of rising interest rates, the Fund can reinvest the proceeds of such prepayments at rates higher than those at which they were previously invested. Mortgages underlying most ARMs, however, have limits on the allowable annual or lifetime increases that can be made in the interest rate that the mortgagor pays. Therefore, if current interest rates rise above such limits over the period of the limitation, the Fund, when holding an ARM, does not benefit from further increases in interest rates. Moreover, when interest rates are in excess of coupon rates (i.e., the rates being paid by mortgagors) of the mortgages, ARMs behave more like fixed income securities and less like adjustable-rate securities and are subject to the risks associated with fixed income securities. In addition, during periods of rising interest rates, increases in the coupon rate of adjustable-rate mortgages generally lag current market interest rates slightly, thereby creating the potential for capital depreciation on such securities.

Stripped Mortgage-Backed Securities. SMBSs are derivative multi-class mortgage securities. SMBSs may be issued by agencies or instrumentalities of the U.S. Government, or by private originators of, or investors in, mortgage loans, including savings and loan associations, mortgage banks, commercial banks, investment banks and special purpose entities of the foregoing. SMBSs are usually structured with two classes that receive different proportions of the interest and principal distributions on a pool of mortgage assets. A common type of SMBS will have one class receiving some of the interest and most of the principal from the mortgage assets, while the other class will receive most of the interest and the remainder of the principal. In the most extreme case, one class will receive all of the interest (the IO class), while the other class will receive all of the principal (the principal-only or PO class). The yield to maturity on an IO class is extremely sensitive to the rate of principal payments (including prepayments) on the related underlying mortgage assets, and a rapid rate of principal payments may have a material adverse effect on the Fund's yield to maturity from these securities. If the underlying mortgage assets experience greater than anticipated prepayments of principal, the Fund may fail to recoup some or all of its initial investment in these securities even if the security is in one of the highest rating categories.

Collateralized Bond Obligations, Collateralized Loan Obligations, and Other Collateralized Debt Obligations. The Fund may invest in each of CBOs, CLOs, other CDOs and other similarly structured securities. CBOs, CLOs and CDOs are types of asset-backed securities. A CBO is a trust which is often backed by a diversified pool of high risk, below investment grade fixed income securities. The collateral can be from many different types of fixed-income securities such as high-yield debt, residential privately-issued mortgage-related securities, commercial privately-issued mortgage-related securities, trust preferred securities and emerging market debt. A CLO is a trust typically collateralized by a pool of loans, which may include, among others, domestic and foreign senior secured loans, senior unsecured loans and subordinate corporate loans, including loans that may be rated below investment grade or equivalent unrated loans. Other CDOs are trusts backed by other types of assets representing obligations of various parties. CBOs, CLOs and other CDOs may charge management fees and administrative expenses. For CBOs, CLOs and CDOs, the cash flows from the trust are split into two or more portions, called tranches, varying in risk and yield. The riskiest portion is the "equity" tranche which bears the bulk of defaults from the bonds or loans in the trust and serves to protect the other, more senior tranches from default in all but the most severe circumstances. Since they are is partially protected from defaults, senior tranches from a CBO trust, CLO trust or trust of another CDO typically have higher ratings and lower yields than their underlying securities, and can be rated investment grade. Despite the protection from the equity tranche, CBO,CLO or other CDO tranches can experience substantial losses due to actual defaults, increased sensitivity to defaults due to collateral default and disappearance of protecting tranches, market anticipation of defaults, as well as aversion to CBO, CLO or other CDO securities as a class. The risks of an investment in a CBO, CLO or other CDO depend largely on the type of the collateral securities and the class of the instrument in which the Fund invests. Normally, CBOs, CLOs and other CDOs are privately offered and sold, and thus, are not registered under the securities laws. As a result, investments in CBOs, CLOs and other CDOs may be characterized by the Fund as illiquid securities; however, an active dealer market may exist for CBOs, CLOs and other CDOs allowing them to qualify for Rule 144A under the 1933 Act. In addition to the normal risks associated with debt instruments discussed elsewhere in this prospectus and in the Statement of Additional Information (e.g., prepayment risk, credit risk, liquidity risk, market risk, structural risk, legal risk and interest rate risk (which may be exacerbated if the interest rate payable on a structured financing changes based on multiples of changes in interest rates or inversely to changes in interest rates) and default risk), CBOs, CLOs and other CDOs carry additional risks including, but not limited to: (i) the possibility that distributions from collateral securities will not be adequate to make interest or other payments; (ii) the quality of the collateral may decline in value or default; (iii) risk that the Fund may invest in CBOs, CLOs or other CDOs that are subordinate to other classes; and (iv) the complex structure of the security may not be fully understood at the time of investment and may produce disputes with the issuer or unexpected investment results.

Asset-Backed Securities. Asset-backed securities ("ABS") are bonds backed by pools of loans or other receivables. ABS are created from many types of assets, including auto loans, credit card receivables, home equity loans and student loans. ABS are typically issued through special purpose vehicles that are bankruptcy remote from the issuer of the collateral. The credit quality of an ABS transaction depends on the performance of the underlying assets. To protect ABS investors from the possibility that some borrowers could miss payments or even default on their loans, ABS include various forms of credit enhancement. Some ABS, particularly home equity loan ABS, are subject to interest rate risk and prepayment risk. A change in interest can affect the pace of payments on the underlying loans, which in turn affects total return on the securities. ABS also carry credit or default risk. If many borrowers on the underlying loans default, losses could exceed the credit enhancement level and result in losses to investors in an ABS. In addition, ABS have structural risk due to a unique characteristic known as early amortization, or early payout, risk. Built into the structure of most ABS are triggers for early payout, designed to protect investors from losses. These triggers are unique to each transaction and can include a big rise in defaults on the underlying loans, a sharp drop in the credit enhancement level or even the bankruptcy of the originator. Once early amortization begins, all incoming loan payments (after expenses are paid) are used to pay investors as quickly as possible based upon a predetermined priority of payment. The Fund may invest in any tranche, including the equity tranche, of ABS.

The Fund may invest in other types of asset-backed securities that are offered in the marketplace, including Enhanced Equipment Trust Certificates ("EETCs"). EETCs are typically issued by specially-created trusts established by airlines, railroads, or other transportation corporations. The proceeds of EETCs are used to purchase equipment, such as airplanes, railroad cars, or other equipment, which in turn serve as collateral for the related issue of the EETCs. The equipment generally is leased by the airline, railroad or other corporation, which makes rental payments to provide the projected cash flow for payments to EETC holders. Holders of EETCs must look to the collateral securing the certificates, typically together with a guarantee provided by the lessee corporation or its parent company for the payment of lease obligations, in the case of default in the payment of principal and

interest on the EETCs. However, because principal and interest payments on EETCs are funded in the ordinary course by the lessee corporation, the Fund treats EETCs as corporate bonds/obligations for purposes of compliance testing and related classifications.

Please see "Investment Objective and Policies—Mortgage-Related and Other Asset-Backed Securities" in the Statement of Additional Information and "Principal Risks of the Fund—Mortgage-Related and Other Asset-Backed Securities Risk" in this prospectus for a more detailed description of the types of mortgage-related and other asset-backed securities in which the Fund may invest and their related risks.

Inflation-indexed bonds (other than municipal inflation-indexed bonds and certain corporate inflation-indexed bonds) are fixed income securities the principal value of which is periodically adjusted according to the rate of inflation. If the index measuring inflation falls, the principal value of inflation-indexed bonds (other than municipal inflation-indexed bonds and certain corporate inflation-indexed bonds) will be adjusted downward, and consequently the interest payable on these securities (calculated with respect to a smaller principal amount) will be reduced. Repayment of the original bond principal upon maturity (as adjusted for inflation) is guaranteed in the case of TIPS. For bonds that do not provide a similar guarantee, the adjusted principal value of the bond repaid at maturity may be less than the original principal. TIPS may also be divided into individual zero-coupon instruments for each coupon or principal payment (known as "iSTRIPS"). An iSTRIP of the principal component of a TIPS issue will retain the embedded deflation floor that will allow the holder of the security to receive the greater of the original principal or inflation-adjusted principal value at maturity. iSTRIPS may be less liquid than conventional TIPS because they are a small component of the TIPS market. Municipal inflation-indexed securities are municipal bonds that pay coupons based on a fixed rate plus CPI. With regard to municipal inflation-indexed bonds and certain corporate inflation-indexed bonds, the inflation adjustment is typically reflected in the semi-annual coupon payment. As a result, the principal value of municipal inflation-indexed bonds and such corporate inflation-indexed bonds does not adjust according to the rate of inflation. At the same time, the value of municipal inflation-indexed securities and such corporate inflation-indexed securities generally will not increase if the rate of inflation decreases. Because municipal inflation-indexed securities and corporate inflation-indexed securities are a small component of the municipal bond and corporate bond markets, respectively, they may be less liquid than conventional municipal and corporate bonds.

The value of inflation-indexed bonds is expected to change in response to changes in real interest rates. Real interest rates are tied to the relationship between nominal interest rates and the rate of inflation. If nominal interest rates increase at a faster rate than inflation, real interest rates may rise, leading to a decrease in value of inflation-indexed bonds. Any increase in the principal amount of an inflation-indexed bond will be considered taxable ordinary income, even though investors do not receive their principal until maturity. See "Taxation" in the Statement of Additional Information.

The Fund may obtain event-linked exposure by investing in "event-linked bonds" or "event-linked swaps" or by implementing "event-linked strategies." Event-linked exposure results in gains or losses that typically are contingent upon, or formulaically related to, defined trigger events. Examples of trigger events include hurricanes, earthquakes, weather-related phenomena or statistics relating to such events. Some event-linked bonds are commonly referred to as "catastrophe bonds." If a trigger event occurs, the Fund may lose a portion or its entire principal invested in the bond or notional amount on a swap. Event-linked exposure often provides for an extension of maturity to process and audit loss claims when a trigger event has, or possibly has, occurred. An extension of maturity may increase volatility. Event-linked exposure may also expose the Fund to certain other risks including credit risk, counterparty risk, adverse regulatory or jurisdictional interpretations and adverse tax consequences. Event-linked exposures may also be subject to liquidity risk.

The Fund may invest in credit-linked trust certificates, which are investments in a limited purpose trust or other vehicle which, in turn, invests in a basket of derivative instruments, such as credit default swaps, total return swaps, interest rate swaps or other securities, in order to provide exposure to the high yield or another debt securities market. Like an investment in a bond, investments in credit-linked trust certificates represent the right to receive periodic income payments (in the form of distributions) and payment of principal at the end of the term of the certificate. However, these payments are conditioned on the trust's receipt of payments from, and the trust's potential obligations to, the counterparties to the derivative instruments and other securities in which the trust invests. For instance, the trust may sell one or more credit default swaps, under which the trust would receive a stream of payments over the term of the swap agreements provided that no event of default has occurred with respect to the referenced debt obligation upon which the swap is based. If a default occurs, the stream of payments may stop and the trust would be obligated to pay to the counterparty the par (or other agreed upon value) of the referenced debt obligation. This, in turn, would reduce the amount of income and principal that the Fund would receive as an investor in the trust. The Fund's investments in these instruments are indirectly subject to the risks associated with derivative instruments, including, among others, credit risk, default or similar event risk, counterparty risk, interest rate risk, leverage risk, valuation risk and management risk. It is expected that the trusts that issue credit-linked trust certificates will constitute "private" investment companies, exempt from registration under the 1940 Act. Therefore, the certificates will not be subject to applicable investment limitations and other regulation imposed by the 1940 Act (although the Fund will remain subject to such limitations and regulation, including with respect to its investments in the certificates). Although the trusts are typically private investment companies, they generally are not actively managed such as a "hedge fund" might be. It also is expected that the certificates will be exempt from registration under the 1933 Act. Accordingly, there may be no established trading market for the certificates and they may constitute illiquid investments. See "Principal Risks of the Fund—Liquidity Risk." If market quotations are not readily available for the certificates, they will be valued by the Fund at fair value as

determined by the Board or persons acting at its direction. See "Net Asset Value." The Fund may lose its entire investment in a credit-linked trust certificate.

An inverse floater is a type of debt instrument that bears a floating or variable interest rate that moves in the opposite direction to interest rates generally or the interest rate on another security or index. Changes in interest rates generally, or the interest rate of the other security or index, inversely affect the interest rate paid on the inverse floater, with the result that the inverse floater's price will be considerably more volatile than that of a fixed-rate bond. The Fund may invest without limit in inverse floaters, which brokers typically create by depositing an income-producing instrument, which may be a mortgage-related security, in a trust. The trust in turn issues a variable rate security and inverse floaters. The interest rate for the variable rate security is typically determined by an index or an auction process, while the inverse floater holder receives the balance of the income from the underlying income-producing instrument less an auction fee. The market prices of inverse floaters may be highly sensitive to changes in interest rates and prepayment rates on the underlying securities, and may decrease significantly when interest rates increase or prepayment rates change. In a transaction in which the Fund purchases an inverse floater from a trust, and the underlying bond was held by the Fund prior to being deposited into the trust, the Fund typically treats the transaction as a secured borrowing for financial reporting purposes. As a result, for financial reporting purposes, the Fund will generally incur a non-cash interest expense with respect to interest paid by the trust on the variable rate securities, and will recognize additional interest income in an amount directly corresponding to the non-cash interest expense. Therefore, the Fund's NAV per Common Share and performance are not affected by the non-cash interest expense. This accounting treatment does not apply to inverse floaters acquired by the Fund when the Fund did not previously own the underlying bond.

A hybrid instrument is a type of potentially high-risk derivative that combines a traditional bond, stock or commodity with an option or forward contract. Generally, the principal amount, amount payable upon maturity or redemption, or interest rate of a hybrid is tied (positively or negatively) to the price of some commodity, currency or securities index or another interest rate or some other economic factor (each a "benchmark"). The interest rate or (unlike most fixed income securities) the principal amount payable at maturity of a hybrid security may be increased or decreased, depending on changes in the value of the benchmark. An example of a hybrid could be a bond issued by an oil company that pays a small base level of interest with additional interest that accrues in correlation to the extent to which oil prices exceed a certain predetermined level. Such a hybrid instrument would be a combination of a bond and a call option on oil.

Hybrids can be used as an efficient means of pursuing a variety of investment goals, including currency hedging, duration management and increased total return. Hybrids may not bear interest or pay dividends. The value of a hybrid or its interest rate may be a multiple of a benchmark and, as a result, may be leveraged and move (up or down) more steeply and rapidly than the benchmark. These benchmarks may be sensitive to economic and political events, such as commodity shortages and currency devaluations, which cannot be readily foreseen by the purchaser of a hybrid. Under certain conditions, the redemption value of a hybrid could be zero. Thus, an investment in a hybrid may entail significant market risks that are not associated with a similar investment in a traditional, U.S. dollar-denominated bond that has a fixed principal amount and pays a fixed rate or floating rate of interest. The purchase of hybrids also exposes the Fund to the credit risk of the issuer of the hybrids. These risks may cause significant fluctuations in the NAV of the Common Shares if the Fund invests in hybrid instruments.

Certain hybrid instruments may provide exposure to the commodities markets. These are derivative securities with one or more commodity-linked components that have payment features similar to commodity futures contracts, commodity options or similar instruments. Commodity-linked hybrid instruments may be either equity or debt securities, leveraged or unleveraged, and are considered hybrid instruments because they have both security and commodity-like characteristics. A portion of the value of these instruments may be derived from the value of a commodity, futures contract, index or other economic variable.

Certain issuers of structured products such as hybrid instruments may be deemed to be investment companies as defined in the 1940 Act. As a result, the Fund's investments in these products may be subject to limits applicable to investments in investment companies and may be subject to restrictions contained in the 1940 Act.

The Fund's use of commodity-linked instruments may be limited by the Fund's intention to qualify as a regulated investment company ("RIC") and may limit the Fund's ability to so qualify. In order to qualify for the special tax treatment accorded RICs and their shareholders, the Fund must, among other things, derive at least 90% of its income from certain specified sources (qualifying income). Income from certain commodity-linked instruments does not constitute qualifying income to the Fund. The tax treatment of certain other commodity-linked instruments in which the Fund might invest is not certain, in particular with respect to whether income and gains from such instruments constitute qualifying income. If the Fund were to treat income from a particular instrument as qualifying income and the income were later determined not to constitute qualifying income and, together with any other nonqualifying income, caused the Fund's nonqualifying income to exceed 10% of its gross income in any taxable year, the Fund would fail to qualify as a RIC unless it is eligible to and does pay a tax at the Fund level. See "Tax Matters."

Variable- and floating-rate instruments are instruments that pay interest at rates that adjust whenever a specified interest rate changes and/or that reset on predetermined dates (such as the last day of a month or calendar quarter). In addition to senior loans, variable- and floating-rate instruments may include, without limitation, instruments such as catastrophe and other event-linked bonds, bank capital securities, unsecured bank loans, corporate bonds, money market instruments and certain types of mortgage-related and other asset-backed securities. Due to their variable- or floating-rate

features, these instruments will generally pay higher levels of income in a rising interest rate environment and lower levels of income as interest rates decline. For the same reason, the market value of a variable- or floating-rate instrument is generally expected to have less sensitivity to fluctuations in market interest rates than a fixed-rate instrument, although the value of a variable- or floating-rate instrument may nonetheless decline as interest rates rise and due to other factors, such as changes in credit quality.

The Fund also may engage in credit spread trades. A credit spread trade is an investment position relating to a difference in the prices or interest rates of two bonds or other securities, in which the value of the investment position is determined by changes in the difference between the prices or interest rates, as the case may be, of the respective securities.

The Fund may invest in a wide variety of bonds of varying maturities issued by non-U.S. (foreign) and U.S. corporations and other business entities, governments and quasi-governmental entities and municipalities and other issuers. Bonds may include, among other things, fixed or variable/floating-rate debt obligations, including bills, notes, debentures, money market instruments and similar instruments and securities. Bonds generally are used by corporations as well as governments and other issuers to borrow money from investors. The issuer pays the investor a fixed or variable rate of interest and normally must repay the amount borrowed on or before maturity. Certain bonds are "perpetual" in that they have no maturity date.

The Fund may enter into, or acquire participations in, delayed funding loans and revolving credit facilities, in which a bank or other lender agrees to make loans up to a maximum amount upon demand by the borrower during a specified term. These commitments may have the effect of requiring the Fund to increase its investment in a company at a time when it might not be desirable to do so (including at a time when the company's financial condition makes it unlikely that such amounts will be repaid). Delayed funding loans and revolving credit facilities are subject to credit, interest rate and liquidity risk and the risks of being a lender.

In order to reduce the interest rate risk inherent in the Fund's underlying investments and capital structure, the Fund may (but is not required to) enter into interest rate swap transactions. Interest rate swaps involve the exchange by the Fund with a counterparty of their respective commitments to pay or receive interest, such as an exchange of fixed rate payments for floating rate payments. These transactions generally involve an agreement with the swap counterparty to pay a fixed or variable rate payment in exchange for the counterparty paying the Fund the other type of payment stream (i.e., variable or fixed). The payment obligation would be based on the notional amount of the swap. Other forms of interest rate swap agreements in which the Fund may invest include, without limitation interest rate caps, under which, in return for a premium one party agrees to make payments to the other to the extent that interest rates exceed a specified rate, or "cap;" interest rate floors, under which, in return for a premium, one party agrees to make payments to the other to the extent that interest rates fall below as specified rate, or "floor;" and interest rate "collars," under which a party sells a cap and purchases a floor or vice versa in an attempt to protect itself against interest rate movements exceeding given minimum or maximum levels. The Fund may (but is not required to) use interest rate swap transactions with the intent to reduce or eliminate the risk that an increase in short-term interest rates could pose for the performance of the Common Shares as a result of leverage, and also may use these instruments for other hedging or investment purposes. The Fund may choose or be required to redeem some or all of the ARPS. This redemption would likely result in the Fund seeking to terminate early all or a portion of any swap or cap transaction. Such early termination of a swap could result in a termination payment by or to the Fund. Any termination of a cap could result in a termination payment to the Fund.

The Fund may invest in "structured" notes and other related instruments, which are privately negotiated debt obligations in which the principal and/or interest is determined by reference to the performance of a benchmark asset, market or interest rate (an "embedded index"), such as selected securities, an index of securities or specified interest rates, or the differential performance of two assets or markets, such as indexes reflecting bonds. Structured instruments may be issued by corporations, including banks, as well as by governmental agencies. Structured instruments frequently are assembled in the form of medium-term notes, but a variety of forms are available and may be used in particular circumstances. The terms of such structured instruments normally provide that their principal and/or interest payments are to be adjusted upwards or downwards (but ordinarily not below zero) to reflect changes in the embedded index while the structured instruments are outstanding. As a result, the interest and/or principal payments that may be made on a structured product may vary widely, depending on a variety of factors, including the volatility of the embedded index and the effect of changes in the embedded index on principal and/or interest payments. The rate of return on structured notes may be determined by applying a multiplier to the performance or differential performance of the referenced index(es) or other asset(s). Application of a multiplier involves leverage that will serve to magnify the potential for gain and the risk of loss.

The Fund may use structured instruments for investment purposes and also for risk management purposes, such as to reduce the duration and interest rate sensitivity of the Fund's portfolio, and for leveraging purposes. While structured instruments may offer the potential for a favorable rate of return from time to time, they also entail certain risks. Structured instruments may be less liquid than other debt securities, and the price of structured instruments may be more volatile. In some cases, depending on the terms of the embedded index, a structured instrument may provide that the principal and/or interest payments may be adjusted below zero. Structured instruments also may involve significant credit risk and risk of default by the counterparty. Structured instruments may also be illiquid. Like other sophisticated strategies, the Fund's use of structured instruments may not work as intended. If the value of the embedded index changes in a manner other than that expected by PIMCO, principal and/or interest payments received on the structured instrument may be substantially less than expected. Also, if PIMCO chooses to use structured instruments to reduce the duration of the Fund's portfolio, this may limit the Fund's return when

having a longer duration would be beneficial (for instance, when interest rates decline).

U.S. Government securities are obligations of and, in certain cases, guaranteed by, the U.S. Government, its agencies or instrumentalities. The U.S. Government does not guarantee the NAV of the Fund's shares. Some U.S. Government securities, such as Treasury bills, notes and bonds, and securities guaranteed by GNMA, are supported by the full faith and credit of the United States; others, such as those of the FHLBs, are supported by the right of the issuer to borrow from the U.S. Department of the Treasury (the "U.S. Treasury"); others, such as those of FNMA, are supported by the discretionary authority of the U.S. Government to purchase the agency's obligations; and still others are supported only by the credit of the instrumentality. U.S. Government securities may include zero coupon securities, which do not distribute interest on a current basis and tend to be subject to greater risk than interest-paying securities of similar maturities.

Municipal bonds share the attributes of debt/fixed income securities in general, but are generally issued by states, municipalities and other political subdivisions, agencies, authorities and instrumentalities of states and multi-state agencies or authorities, and may be either taxable or tax-exempt instruments. The municipal bonds that the Fund may purchase include without limit general obligation bonds and limited obligation bonds (or revenue bonds), including industrial development bonds issued pursuant to former federal tax law. General obligation bonds are obligations involving the credit of an issuer possessing taxing power and are payable from such issuer's general revenues and not from any particular source. Limited obligation bonds are payable only from the revenues derived from a particular facility or class of facilities or, in some cases, from the proceeds of a special excise or other specific revenue source. Tax exempt private activity bonds and industrial development bonds generally are also limited obligation bonds and thus are not payable from the issuer's general revenues. The credit and quality of private activity bonds and industrial development bonds are usually related to the credit of the corporate user of the facilities. Payment of interest on and repayment of principal of such bonds is the responsibility of the corporate user (and/or any guarantor).

The Fund may invest in Build America Bonds, which are tax credit bonds created by the American Recovery and Reinvestment Act of 2009, which authorizes state and local governments to issue Build America Bonds as taxable bonds in 2009 and 2010, without volume limitations, to finance any capital expenditures for which such issuers could otherwise issue traditional tax-exempt bonds. State and local governments may receive a direct federal subsidy payment for a portion of their borrowing costs on Build America Bonds equal to 35% of the total coupon interest paid to investors. The state or local government issuer can elect to either take the federal subsidy or pass the 35% tax credit along to bondholders. The Fund's investments in Build America Bonds will result in taxable income and the Fund may elect to pass through to shareholders the corresponding tax credits. The tax credits can generally be used to offset federal income taxes and the alternative minimum tax, but such credits are generally not refundable. Build America Bonds involve similar risks as municipal bonds, including credit and market risk. They are intended to assist state and local governments in financing capital projects at lower borrowing costs and are likely to attract a broader group of investors than tax-exempt municipal bonds. For example, taxable funds, such as the Fund, may choose to invest in Build America Bonds. Although Build America Bonds were only authorized for issuance during 2009 and 2010, the program may have resulted in reduced issuance of tax-exempt municipal bonds during the same period. The Build America Bond program expired on December 31, 2010, at which point no further issuance of new Build America Bonds was permitted. As of the date of this prospectus, there is no indication that Congress will renew the program to permit issuance of new Build America Bonds.

The Fund may invest in pre-refunded municipal bonds. Pre-refunded municipal bonds are tax-exempt bonds that have been refunded to a call date prior to the final maturity of principal, or, in the case of pre-refunded municipal bonds commonly referred to as "escrowed-to-maturity bonds," to the final maturity of principal, and remain outstanding in the municipal market. The payment of principal and interest of the pre-refunded municipal bonds held by the Fund is funded from securities in a designated escrow account that holds U.S. Treasury securities or other obligations of the U.S. Government (including its agencies and instrumentalities ("Agency Securities")). Interest payments on pre-refunded municipal bonds issued on or prior to December 31, 2017 are exempt from federal income tax; pre-refunded municipal bonds issued after December 31, 2017 will not qualify for such tax-advantaged treatment. Pre-refunded municipal bonds will bear an AAA/Aaa rating (if a re-rating has been requested and paid for) because they are backed by U.S. Treasury securities or Agency Securities. Because the payment of principal and interest is generated from securities held in an escrow account established by the municipality and an independent escrow agent, the pledge of the municipality has been fulfilled and the original pledge of revenue by the municipality is no longer in place. The escrow account securities pledged to pay the principal and interest of the pre-refunded municipal bond do not guarantee the price movement of the bond before maturity. Issuers of municipal bonds refund in advance of maturity the outstanding higher cost debt and issue new, lower cost debt, placing the proceeds of the lower cost issuance into an escrow account to pre-refund the older, higher cost debt. Investment in pre-refunded municipal bonds held by the Fund may subject the Fund to interest rate risk and market risk. In addition, while a secondary market exists for pre-refunded municipal bonds, if the Fund sells pre-refunded municipal bonds prior to maturity, the price received may be more or less than the original cost, depending on market conditions at the time of sale.

The Fund may invest in municipal lease obligations. A lease is not a full faith and credit obligation of the issuer and is usually backed only by the borrowing government's unsecured pledge to make annual appropriations for lease payments. There have been challenges to the legality of lease financing in numerous states, and, from time to time, certain municipalities have considered not appropriating money for lease payments. In deciding whether to purchase a lease obligation for the Fund, PIMCO will assess the financial condition of the borrower, the merits of the project, the level of public support for the project and the legislative history of lease financing in

the state. These securities may be less readily marketable than other municipal securities.

Some longer-term municipal bonds give the investor the right to "put" or sell the security at par (face value) within a specified number of days following the investor's request—usually one to seven days. This demand feature enhances a security's liquidity by shortening its effective maturity and enables it to trade at a price equal to or very close to par. If a demand feature terminates prior to being exercised, the Fund would hold the longer-term security, which could experience substantially more volatility.

The Fund may invest in municipal warrants, which are essentially call options on municipal bonds. In exchange for a premium, municipal warrants give the purchaser the right, but not the obligation, to purchase a municipal bond in the future. The Fund may purchase a warrant to lock in forward supply in an environment in which the current issuance of bonds is sharply reduced. Like options, warrants may expire worthless and may have reduced liquidity.

The Fund may invest in municipal bonds with credit enhancements such as letters of credit, municipal bond insurance and standby bond purchase agreements ("SBPAs"). Letters of credit are issued by a third party, usually a bank, to enhance liquidity and to ensure repayment of principal and any accrued interest if the underlying municipal bond should default. Municipal bond insurance, which is usually purchased by the bond issuer from a private, nongovernmental insurance company, provides an unconditional and irrevocable guarantee that the insured bond's principal and interest will be paid when due. Insurance does not guarantee the price of the bond. The credit rating of an insured bond reflects the credit rating of the insurer, based on its claims-paying ability. The obligation of a municipal bond insurance company to pay a claim extends over the life of each insured bond. Although defaults on insured municipal bonds have been low to date and municipal bond insurers have met their claims, there is no assurance that this will continue. A higher-than expected default rate could strain the insurer's loss reserves and adversely affect its ability to pay claims to bondholders. Because a significant portion of insured municipal bonds that have been issued and are outstanding is insured by a small number of insurance companies, not all of which have the highest credit rating, an event involving one or more of these insurance companies, such as a credit rating downgrade, could have a significant adverse effect on the value of the municipal bonds insured by such insurance company or companies and on the municipal bond markets as a whole. An SBPA is a liquidity facility provided to pay the purchase price of bonds that cannot be re-marketed. The obligation of the liquidity provider (usually a bank) is only to advance funds to purchase tendered bonds that cannot be re-marketed and does not cover principal or interest under any other circumstances. The liquidity provider's obligations under the SBPA are usually subject to numerous conditions, including the continued creditworthiness of the underlying borrower.

For instance, in connection with the restructuring of a debt instrument, either outside of bankruptcy court or in the context of bankruptcy court proceedings, the Fund may determine or be required to accept common stocks or other equity securities in exchange for all or a portion of the debt instrument. Depending upon, among other things, PIMCO's evaluation of the potential value of such securities in relation to the price that could be obtained by the Fund at any given time upon sale thereof, the Fund may determine to hold these equity securities in its portfolio.

Although common stocks and other equity securities have historically generated higher average returns than debt securities over the long term, they also have experienced significantly more volatility in those returns and in certain years have significantly underperformed relative to debt securities. An adverse event, such as an unfavorable earnings report, may depress the value of a particular equity security held by the Fund. Also, prices of common stocks and other equity securities are sensitive to general movements in the equity markets and a decline in those markets may depress the prices of the equity securities held by the Fund. The prices of equity securities fluctuate for many different reasons, including changes in investors' perceptions of the financial condition of an issuer or the general condition of the relevant stock market or when political or economic events affecting the issuer occur. In addition, prices of equity securities may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. The Fund may invest in common shares of pooled vehicles, such as those of other open- and closed- end investment companies, and in common shares of REITs.

The Fund may purchase securities that it is eligible to purchase on a when-issued basis, may purchase and sell such securities for delayed delivery and may make contracts to purchase such securities for a fixed price at a future date beyond normal settlement time (forward commitments). When-issued transactions, delayed delivery purchases and forward commitments involve a risk of loss if the value of the securities declines prior to the settlement date. The risk is in addition to the risk that the Fund's other assets will decline in value. Therefore, these transactions may result in a form of leverage and increase the Fund's overall investment exposure. Typically, no income accrues on securities the Fund has committed to purchase prior to the time delivery of the securities is made, although the Fund may earn income on securities it has segregated to cover these positions. When the Fund has sold a security on a when-issued, delayed delivery or forward commitment basis, the Fund does not participate in future gains or losses with respect to the security. If the other party to a transaction fails to pay for the securities, the Fund could suffer a loss. Additionally, when selling a security on a when-issued, delayed delivery or forward commitment basis without owning the security, the Fund will incur a loss if the security's price appreciates in value such that the security's price is above the agreed-upon price on the settlement date.

The Fund may enter into repurchase agreements, in which the Fund purchases a security from a bank or broker-dealer and the bank or broker-dealer agrees to repurchase the security at the Fund's cost plus interest within a specified time. If the party agreeing to repurchase should default, the Fund will seek to sell the securities it holds. This could involve transaction costs or delays in addition to a loss on the securities if their value should fall below their repurchase price. Repurchase agreements maturing in more than seven days are considered to be illiquid securities.

As described under "Use of Leverage," the Fund may use, among other things, reverse repurchase agreements and/or dollar rolls to add leverage to its portfolio. Under a reverse repurchase agreement, the Fund sells securities to a bank or broker dealer and agrees to repurchase the securities at a mutually agreed future date and price. A dollar roll is similar to a reverse repurchase agreement except that the counterparty with which the Fund enters into a dollar roll transaction is not obligated to return the same securities as those originally sold by the Fund, but only securities that are "substantially identical." Generally, the effect of a reverse repurchase agreement or dollar roll transaction is that the Fund can recover and reinvest all or most of the cash invested in the portfolio securities involved during the term of the agreement and still be entitled to the returns associated with those portfolio securities, thereby resulting in a transaction similar to a borrowing and giving rise to leverage for the Fund. The Fund will incur interest expense as a cost of utilizing reverse repurchase agreements and dollar rolls. In the event the buyer of securities under a reverse repurchase agreement or dollar roll files for bankruptcy or becomes insolvent, the Fund's use of the proceeds of the agreement may be restricted pending a determination by the other party, or its trustee or receiver, whether to enforce the Fund's obligation to repurchase the securities.

The Fund may invest in securities of other open- or closed-end investment companies, including without limit ETFs, to the extent that such investments are consistent with the Fund's investment objective, strategies and policies and permissible under the 1940 Act. The Fund may invest in other investment companies to gain broad market or sector exposure, including during periods when it has large amounts of uninvested cash (such as the period shortly after the Fund receives the proceeds of the offering of its Common Shares) or when PIMCO believes share prices of other investment companies offer attractive values. As a shareholder in an investment company, the Fund would bear its ratable share of that investment company's expenses and would remain subject to payment of the Fund's management fees and other expenses with respect to assets so invested. Common Shareholders would therefore be subject to duplicative expenses to the extent the Fund invests in other investment companies. The securities of other investment companies may be leveraged, in which case the NAV and/or market value of the investment company's shares will be more volatile than unleveraged investments. See "Principal Risks of the Fund—Leverage Risk."

A short sale is a transaction in which the Fund sells a security or other instrument that it does not own in anticipation that the market price will decline. The Fund may use short sales for investment purposes or for hedging and risk management purposes. The Fund may also take short positions with respect to the performance of securities, indexes, interest rates, currencies and other assets or markets through the use of derivative or forward instruments. When the Fund engages in a short sale of a security, it must borrow the security sold short and deliver it to the counterparty. The Fund may have to pay a fee to borrow particular securities and would often be obligated to pay over any payments received on such borrowed securities. The Fund's obligation to replace the borrowed security will be secured by collateral deposited with the Fund's custodian in the name of the lender. The Fund may not receive any payments (including interest) on its collateral. Short sales expose the Fund to the risk that it will be required to cover its short position at a time when the securities have appreciated in value, thus resulting in a loss to the Fund. The Fund may engage in so-called "naked" short sales when it does not own or have the immediate right to acquire the security sold short at no additional cost, in which case the Fund's losses theoretically could be unlimited. If the price of the security sold short increases between the time of the short sale and the time that the Fund replaces the borrowed security, the Fund will incur a loss; conversely, if the price declines, the Fund will realize a gain. Any gain will be decreased, and any loss increased, by the transaction costs described above. The successful use of short selling may be adversely affected by imperfect correlation between movements in the price of the security sold short and securities being hedged if the short sale is being used for hedging purposes. See "Principal Risks of the Fund—Derivatives" and "Principal Risks of the Fund—Short Sales Risk." See also "Principal Risks of the Fund—Leverage Risk" and "Principal Risks of the Fund—Segregation and Coverage Risk." The Fund may engage in short selling to the extent permitted by the 1940 Act and other federal securities laws.

For the purpose of achieving income, the Fund may lend its portfolio securities to brokers, dealers or other financial institutions provided a number of conditions are satisfied, including that the loan is fully collateralized. See "Investment Objective and Policies—Loans of Portfolio Securities" in the Statement of Additional Information for details. When the Fund lends portfolio securities, its investment performance will continue to reflect changes in the value of the securities loaned. The Fund will also receive a fee or interest on the collateral. Securities lending involves the risk of loss of rights in the collateral or delay in recovery of the collateral if the borrower fails to return the security loaned or becomes insolvent, or the risk of loss due to the investment performance of the collateral. The Fund may pay lending fees to the party arranging the loan. See "Principal Risks of the Fund—Securities Lending Risk."

The length of time the Fund has held a particular security is not generally a consideration in investment decisions. A change in the securities held by the Fund is known as "portfolio turnover." The Fund may engage in frequent and active trading of portfolio securities to achieve its investment objective,

particularly during periods of volatile market movements. High portfolio turnover (e.g., over 100%) generally involves correspondingly greater expenses to the Fund, including brokerage commissions or dealer mark-ups and other transaction costs on the sale of securities and reinvestments in other securities. Sales of portfolio securities may also result in realization of taxable capital gains, including short-term capital gains (which are generally treated as ordinary income upon distribution in the form of dividends). The trading costs and tax effects associated with portfolio turnover may adversely affect the Fund's performance.

In connection with rating the ARPS, Moody's will impose asset coverage tests and other restrictions that may limit the Fund's ability to engage in certain of the transactions described above. See "Description of Capital Structure".

Please see "Investment Objective and Policies" in the Statement of Additional Information for additional information regarding the investments of the Fund and their related risks.

The Fund utilizes leverage through its outstanding Preferred Shares and may obtain additional leverage through reverse repurchase agreements, dollar rolls or borrowings, such as through bank loans or commercial paper and/ or other credit facilities. The amount of leverage the Fund utilizes may vary, but the Fund will not incur leverage (including preferred shares and other forms of leverage) in an amount exceeding 50% of its total assets. Information regarding the terms and features of the Preferred Shares is provided under "Description of Capital Structure" in this prospectus.

Depending upon market conditions and other factors, the Fund may or may not determine to add leverage following an offering to maintain or increase the total amount of leverage (as a percentage of the Fund's total assets) that the Fund currently maintains, taking into account the additional assets raised through the issuance of Common Shares in such offering. The Fund utilizes certain kinds of leverage, such as reverse repurchase agreements and credit default swaps, opportunistically and may choose to increase or decrease, or eliminate entirely, its use of such leverage over time and from time to time based on PIMCO's assessment of the yield curve environment, interest rate trends, market conditions and other factors. The Fund may also determine to decrease the leverage it currently maintains through its outstanding Preferred Shares through Preferred Shares redemptions or tender offers and may or may not determine to replace such leverage through other sources. If the Fund determines to add leverage following an offering, it is not possible to predict with accuracy the precise amount of leverage that would be added, in part because it is not possible to predict the number of Common Shares that ultimately will be sold in an offering or series of offerings. To the extent that the Fund does not add additional leverage following an offering, the Fund's total amount of leverage as a percentage of its total assets will decrease, which could result in a reduction of investment income available for distribution to Common Shareholders.

Regarding the costs associated with the Fund's Preferred Shares, the terms of the ARPS provide that they would ordinarily pay dividends at a rate set at auctions held every seven days, normally payable on the first business day following the end of the rate period, subject to a maximum applicable rate calculated as a function of the ARPS' then-current rating and a reference interest rate, as described below. However, the weekly auctions for the ARPS, as well as auctions for similar preferred shares of other closed-end funds in the U.S., have failed since February 2008, and the dividend rates on the ARPS since that time have been paid at the maximum applicable rate (i.e. a multiple of a reference rate, which is the applicable "AA" Financial Composite Commercial Paper Rate (for a dividend period of fewer than 184 days) or the applicable Treasury Index Rate (for a dividend period of 184 days or more)). In September 2011, Moody's, a ratings agency that provides ratings for the Fund's ARPS, downgraded its rating of the ARPS from "Aaa" to "A2," citing persistently thin asset coverage levels, increased NAV volatility and concerns about secondary market liquidity for some assets supporting rated obligations. In July 2012, Moody's downgraded its rating of the ARPS from "A2" to "A3" pursuant to a revised ratings methodology adopted by Moody's. Also, in May 2014, Moody's upgraded its rating of the Fund's ARPS from A3 to A2, citing changes in the Fund's asset coverage ratio and economic leverage. Under the Fund's amended and restated bylaws (the "Bylaws"), the 2011 downgrade resulted in an increase in the multiple used to calculate the maximum applicable rate from 150% to 200%, thereby increasing the dividend rate payable to ARPS holders and increasing the costs to Common Shareholders associated with the Fund's leverage. See "Description of Capital Structure." The Fund expects that the ARPS will continue to pay dividends at the maximum applicable rate for the foreseeable future and cannot predict whether or when the auction markets for the ARPS may resume normal functioning. See "Principal Risks of the Fund—Leverage Risk," "Principal Risks of the Fund— Additional Risks Associated with the Fund's Preferred Shares" and "Description of Capital Structure" for more information.

Under the 1940 Act, the Fund is not permitted to issue new preferred shares unless immediately after such issuance the value of the Fund's total net assets (as defined below) is at least 200% of the liquidation value of

the outstanding Preferred Shares and the newly issued preferred shares plus the aggregate amount of any senior securities of the Fund representing indebtedness (i.e., such liquidation value plus the aggregate amount of senior securities representing indebtedness may not exceed 50% of the Fund's total net assets). In addition, the Fund is not permitted to declare any cash dividend or other distribution on its Common Shares unless, at the time of such declaration, the value of the Fund's total net assets satisfies the above-referenced 200% coverage requirement.

Leveraging is a speculative technique and there are special risks and costs involved. The Fund cannot assure you that its Preferred Shares and use of any other forms of leverage (such as the use of reverse repurchase agreements or derivatives strategies), if any, will result in a higher yield on your Common Shares. When leverage is used, the NAV and market price of the Common Shares and the yield to Common Shareholders will be more volatile. See "Principal Risks of the Fund—Leverage Risk." In addition, dividend, interest and other costs and expenses borne by the Fund with respect to its Preferred Shares and its use of any other forms of leverage are borne by the Common Shareholders (and not by the holders of Preferred Shares) and result in a reduction of the NAV of the Common Shares. In addition, because the fees received by the Investment Manager are based on the average daily net assets of the Fund (including any assets attributable to any outstanding Preferred Shares), the Investment Manager has a financial incentive for the Fund to use Preferred Shares, which may create a conflict of interest between the Investment Manager, on the one hand, and the Common Shareholders, on the other hand. The fees received by the Investment Manager are not, however, charged on asset attributable to leverage obtained by the Fund other than through preferred shares.

The Fund's ability to utilize leverage is also limited by asset coverage requirements and other guidelines imposed by rating agencies (currently Moody's) that provide ratings for the ARPS, which may be more restrictive than the limitations imposed by the 1940 Act noted above. See "Description of Capital Structure" for more information.

The following table is furnished in response to requirements of the SEC. It is designed to illustrate the effects of leverage through the use of senior securities, as that term is defined under Section 18 of the 1940 Act, on Common Share total return, assuming investment portfolio total returns (consisting of income and changes in the value of investments held in the Fund's portfolio) of -10%, -5%, 0%, 5% and 10%. The table below assumes the Fund's continued use of Preferred Shares as of January 31, 2018, representing approximately 13.77% of the Fund's total managed assets, and, although not senior securities under the 1940 Act, covered reverse repurchase agreements as of January 31, 2018, representing approximately 15.76% of the Fund's total managed assets. The table below also assumes that the Fund will pay dividends on Preferred Shares at an estimated annual effective Preferred Share dividend rate of 2.82% (based on the Preferred Share dividend rate as of January 31, 2018) and interest on reverse repurchase agreements at an estimated annual effective interest expense rate of 1.85% (based on market interest rates as of January 31, 2018). Based on such estimates, the annual return that the Fund's portfolio must experience (net of expenses) in order to cover such costs is 0.68%. The information below does not reflect the Fund's use of certain other forms of economic leverage achieved through the use of other instruments or transactions not considered to be senior securities under the 1940 Act, such as covered credit default swaps or other derivative instruments.

These assumed investment portfolio returns are hypothetical figures and are not necessarily indicative of the investment portfolio returns experienced or expected to be experienced by the Fund. Your actual returns may be greater or less than those appearing below. In addition, actual borrowing expenses associated with reverse repurchase agreements (or dollar rolls or borrowings, if any) used by the Fund may vary frequently and may be significantly higher or lower that the rate used for the example below.

Common Share total return is composed of two elements — the Common Share dividends paid by the Fund (the amount of which is largely determined by the net investment income of the Fund after paying dividends on Preferred Shares and expenses on any forms of leverage outstanding) and gains or losses on the value of the securities and other instruments the Fund owns. As required by SEC rules, the table assumes that the Fund is more likely to suffer capital losses than to enjoy capital appreciation. For example, to assume a total return of 0%, the Fund must assume that the income it receives on its investments is entirely offset by losses in the value of those investments. This table reflects hypothetical performance of the Fund's portfolio and not the actual performance of the Fund's Common Shares, the value of which is determined by market forces and other factors.

Should the Fund elect to add additional leverage to its portfolio following an offering, any benefits of such additional leverage cannot be fully achieved until the proceeds resulting from the use of such leverage have been received by the Fund and invested in accordance with the Fund's investment objective and policies. As noted above, the Fund's willingness to use additional leverage, and the extent to which leverage is used at any time, will depend on many factors, including, among other things, PIMCO's assessment of the yield curve environment, interest rate trends, market conditions and other factors.

In general, lower rated debt securities carry a greater degree of risk that the issuer will lose its ability to make interest and principal payments, which could have a negative effect on the NAV of the Fund's Common Shares or Common Share dividends. Securities of below investment grade quality are regarded as having predominantly speculative characteristics with respect to capacity to pay interest and repay principal, and are commonly referred to as "high yield" securities or "junk bonds." High yield securities involve a greater risk of default and their prices are generally more volatile and sensitive to actual or perceived negative developments, such as a decline in the issuer's revenues or revenues of underlying borrowers or a general economic downturn, than are the prices of higher grade securities. Debt securities in the lowest investment grade category also may be considered to possess some speculative characteristics by certain rating agencies. The Fund may purchase distressed securities that are in default or the issuers of which are in bankruptcy, which involve heightened risks. See "Principal Risks of the Fund—Distressed and Defaulted Securities Risk. An economic downturn could severely affect the ability of issuers (particularly those that are highly leveraged) to service their debt obligations or to repay their obligations upon maturity. Lower-rated securities are generally less liquid than higher-rated securities, which may have an adverse effect on the Fund's ability to dispose of a particular security. For example, under adverse market or economic conditions, the secondary market for below investment grade securities could contract further, independent of any specific adverse changes in the condition of a particular issuer, and certain securities in the Fund's portfolio may become illiquid or less liquid. As a result, the Fund could find it more difficult to sell these securities or may be able to sell these securities only at prices lower than if such securities were widely traded. See "Principal Risks of the Fund—Liquidity Risk." To the extent the Fund focuses on below investment grade debt obligations, PIMCO's capabilities in analyzing credit quality and associated risks will be

particularly important, and there can be no assurance that PIMCO will be successful in this regard. See "Portfolio Contents—High Yield Securities" for additional information. Due to the risks involved in investing in high yield securities, an investment in the Fund should be considered speculative.

The Fund's credit quality policies apply only at the time a security is purchased, and the Fund is not required to dispose of a security in the event that a rating agency or PIMCO downgrades its assessment of the credit characteristics of a particular issue. In determining whether to retain or sell such a security, PIMCO may consider factors including, but not limited to, PIMCO's assessment of the credit quality of the issuer of such security, the price at which such security could be sold and the rating, if any, assigned to such security by other rating agencies. Analysis of creditworthiness may be more complex for issuers of high yield securities than for issuers of higher quality debt securities.

Current market conditions may pose heightened risks with respect to funds that invest in fixed income securities. As discussed more under "—Interest Rate Risk," interest rates in the U.S. are near historically low levels. However, continued economic recovery, the end of the Federal Reserve Board's quantitative easing program, and an increased likelihood of a rising interest rate environment increase the risk that interest rates will continue to rise in the near future. Any further interest rate increases in the future could cause the value of the Fund to decrease. As such, fixed income securities markets may experience heightened levels of interest rate, volatility and liquidity risk.

affect the income received from such securities and the NAV of the Fund's shares.

During periods of very low or negative interest rates, the Fund may be unable to maintain positive returns. Interest rates in the United States and many parts of the world, including certain European countries, are at or near historically low levels. Certain European countries have recently experienced negative interest rates on certain fixed income instruments. Very low or negative interest rates may magnify interest rate risk. Changing interest rates, including rates that fall below zero, may have unpredictable effects on markets, may result in heightened market volatility and may detract from Fund performance to the extent the Fund is exposed to such interest rates.

The Fund's use of leverage (as described under "Use of Leverage" in the body of this prospectus) creates the opportunity for increased Common Share net income, but also creates special risks for Common Shareholders. To the extent used, there is no assurance that the Fund's leveraging strategies will be successful. Leverage is a speculative technique that may expose the Fund to greater risk and increased costs. The Fund's assets attributable to its outstanding Preferred Shares or the net proceeds that the Fund obtains from its use of reverse repurchase agreements, dollar rolls and/or borrowings, if any, will be invested in accordance with the Fund's investment objective and policies as described in this prospectus. Dividends payable with respect to the Preferred Shares and interest expense payable by the Fund with respect to any reverse repurchase agreements, dollar rolls and borrowings (for dividends payable with respect to Preferred Shares) will generally be based on shorter-term interest rates that would be periodically reset. So long as the Fund's portfolio investments provide a higher rate of return (net of applicable Fund expenses) than the dividend rate on the Preferred Shares and the interest expenses and other costs to the Fund of such other leverage, the investment of the proceeds thereof will generate more income than will be needed to pay the costs of the leverage. If so, and all other things being equal, the excess may be used to pay higher dividends to Common Shareholders than if the Fund were not so leveraged. If, however, shorter-term interest rates rise relative to the rate of return on the Fund's portfolio, the interest and other costs of leverage to the Fund (including interest expenses on reverse repurchase agreements, dollar rolls and borrowings and the dividend rate on any outstanding preferred shares) could exceed the rate of return on the debt obligations and other investments held by the Fund, thereby reducing return to Common Shareholders. In addition, fees and expenses of any form of leverage used by the Fund will be borne entirely by the Common Shareholders (and not by preferred shareholders, if any) and will reduce the investment return of the Common Shares. Therefore, there can be no assurance that the Fund's use of leverage will result in a higher yield on the Common Shares, and it may result in losses. In addition, any Preferred Shares issued by the Fund are expected to pay cumulative dividends, which may tend to increase leverage risk.
Leverage creates several major types of risks for Common Shareholders, including:

the likelihood of greater volatility of NAV and market price of Common Shares, and of the investment return to Common Shareholders, than a comparable portfolio without leverage;

In addition, holders of ARPS and any other preferred shareholders of the Fund, and the counterparties to the Fund's other leveraging transactions,

The use by the Fund of reverse repurchase agreements and dollar rolls to obtain leverage also involves special risks. For instance, the market value of the securities that the Fund is obligated to repurchase under a reverse repurchase agreement or dollar roll may decline below the repurchase price. See "The Fund's Investment Objective and Policies—Portfolio Contents—Reverse Repurchase Agreements and Dollar Rolls."

In addition to reverse repurchase agreements, dollar rolls and/or borrowings (or a future issuance of preferred shares), the Fund may engage in other transactions that may give rise to a form of leverage including, among others, futures and forward contracts (including foreign currency exchange contracts), credit default swaps, total return swaps, basis swaps and other derivative transactions, loans of portfolio securities, short sales and when-issued, delayed delivery and forward commitment transactions). The Fund's use of such transactions gives rise to associated leverage risks described above, and may adversely affect the Fund's income, distributions and total returns to Common Shareholders. The Fund manages some of its derivative positions by segregating an amount of cash or liquid securities equal to the notional value or the market value, as applicable, of those positions. See "Segregation and Coverage Risk." The Fund may also offset derivatives positions against one another or against other assets to manage effective market exposure resulting from derivatives in its portfolio. To the extent that any offsetting positions do not behave in relation to one another as expected, the Fund may perform as if it is leveraged through use of these derivative strategies. See "Use of Leverage."

Although the Fund's ARPS ordinarily would pay dividends at rates set at periodic auctions, the weekly auctions for the ARPS (and auctions for similar preferred shares issued by closed-end funds in the U.S.) have failed since February 2008. The dividend rates on the ARPS since that time have been paid, and the Fund expects that they will continue to be paid for the foreseeable future, at the "maximum applicable rate" under the Fund's Bylaws (i.e., a multiple of a reference rate, which is the applicable "AA" Financial Composite Commercial Paper Rate (for a dividend period of fewer than 184 days) or the applicable Treasury Index Rate (for a dividend period of 184 days or more)). An increase in market interest rates generally, therefore, could increase substantially the dividend rate required to be paid by the Fund to the holders of ARPS, which would increase the expenses associated with the Fund's leverage and reduce the Fund's net income available for distribution to Common Shareholders.

may require the Fund to redeem ARPS. See "Description of Capital Structure." Failure to satisfy ratings agency asset coverage tests or other guidelines could also result in the applicable ratings agency downgrading its then-current ratings on the ARPS, as described above. Moreover, the rating agency guidelines impose restrictions or limitations on the Fund's use of certain financial instruments or investment techniques that the Fund might otherwise utilize in order to achieve its investment objective, which may adversely affect the Fund's investment performance. Rating agency guidelines may be modified by the rating agencies in the future and, if adopted by the Fund, such modifications may make such guidelines substantially more restrictive, which could further negatively affect the Fund's investment performance.

has invested, 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.

and a smaller number of traded securities. There may be little publicly available information about issuers. Settlement, clearing and registration of securities transactions are subject to risks because of registration systems that may not be subject to effective government supervision. This may result in significant delays or problems in registering the transfer of securities. Russian securities laws may not recognize foreign nominee accounts held with a custodian bank, and therefore the custodian may be considered the ultimate owner of securities they hold for their clients. Ownership of securities issued by Russian companies is recorded by companies themselves and by registrars instead of through a central registration system. It is possible that the ownership rights of the Fund could be lost through fraud or negligence. While applicable Russian regulations impose liability on registrars for losses resulting from their errors, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities in the event of loss of share registration. Adverse currency exchange rates are a risk and there may be a lack of available currency hedging instruments. Investments in Russia may be subject to the risk of nationalization or expropriation of assets. Oil, natural gas, metals, and timber account for a significant portion of Russia's exports, leaving the country vulnerable to swings in world prices.

There is a heightened possibility of imposition of withholding taxes on interest or dividend income generated from emerging market securities. Governments of emerging market countries may engage in confiscatory taxation or expropriation of income and/or assets to raise revenues or to pursue a domestic political agenda. In the past, emerging market countries have nationalized assets, companies and even entire sectors, including the assets of foreign investors, with inadequate or no compensation to the prior owners. There can be no assurance that the Fund will not suffer a loss of any or all of its investments or, interest or dividends thereon, due to adverse fiscal or other policy changes in emerging market countries.

contracts (including foreign currency exchange contracts), call and put options, credit default swaps, total return swaps, basis swaps and other swap agreements. The Fund may also have exposure to derivatives, such as interest rate or credit-default swaps, through investment in credit-linked trust certificates and other securities issued by special purpose or structured vehicles. The Fund's use of derivative instruments involves risks different from, and possibly greater than, the risks associated with investing directly in securities and other traditional investments. Derivatives are subject to a number of risks described elsewhere in this prospectus, such as liquidity risk, interest rate risk, issuer risk, credit risk, leveraging risk, counterparty risk and management risk. See "Principal Risks of the Fund—Segregation and Coverage Risk." They also involve the risk of mispricing or improper valuation, the risk of unfavorable or ambiguous documentation and the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. If the Fund invests in a derivative instrument, it could lose more than the principal amount invested. Also, suitable derivative transactions may not be available in all circumstances and there can be no assurance that the Fund will engage in these transactions to reduce exposure to other risks when that would be beneficial. The Fund's use of derivatives also may affect the amount, timing, or character of distributions to, and taxes payable by, Common Shareholders. See "Tax Matters." 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. For derivatives traded on an exchange or through a central counterparty, credit risk resides with the creditworthiness of the Fund's clearing broker, or the clearinghouse itself, rather than to a counterparty in an OTC derivative transaction.

The Fund may invest in a variety of mortgage-related and other asset-backed securities issued by government agencies or other governmental entities or by private originators or issuers.

In addition to credit risk (see "Credit Risk") and possibly high yield risk (see "High Yield Securities Risk"), investment in preferred securities involves certain other risks. Certain preferred securities contain provisions that allow an issuer under certain conditions to skip or defer distributions. If the Fund owns a preferred security that is deferring its distribution, the Fund may be required to include the amount of the deferred distribution in its taxable income for tax purposes despite the fact that it does not currently receive such amount. In order to receive the special treatment accorded to RICs and their shareholders under the Code and to avoid U.S. federal income and/or excise taxes at the Fund level, the Fund may be required to distribute this income to shareholders in the tax year in which the income is recognized (without a corresponding receipt of cash). Therefore, the Fund may be required to pay out as an income distribution in any such tax year an amount greater than the total amount of cash income the Fund actually received, and to sell portfolio securities, including at potentially disadvantageous times or prices, to obtain cash needed for these income distributions. Preferred securities often are subject to legal provisions that allow for redemption in the event of certain tax or legal changes or at the issuer's call. In the event of redemption, the Fund may not be able to reinvest the proceeds at comparable rates of return. Preferred securities are subordinated to bonds and other debt securities in an issuer's capital structure in terms of priority for corporate income and liquidation payments, and therefore will be subject to greater credit risk than those debt securities. Preferred securities may trade less frequently and in a more limited volume and may be subject to more abrupt or erratic price movements than many other securities, such as common stocks, corporate debt securities and U.S. Government securities.

Inflation-indexed debt securities are subject to the effects of changes in market interest rates caused by factors other than inflation (real interest rates). In general, the value of an inflation-indexed security, including TIPS, tends to decrease when real interest rates increase and can increase when real interest rates decrease. Thus generally, during periods of rising inflation, the value of inflation-indexed securities will tend to increase and during periods of deflation, their value will tend to decrease. Interest payments on inflation-indexed securities are unpredictable and will fluctuate as the principal and interest are adjusted for inflation. There can be no assurance that the inflation index used (i.e., the CPI) will accurately measure the real rate of inflation in the prices of goods and services. Increases in the principal value of TIPS due to inflation are considered taxable ordinary income for the amount of the increase in the calendar year. Any increase in the principal amount of an inflation-indexed debt security will be considered taxable ordinary income, even though the Fund will not receive the principal until maturity. Additionally, a CPI swap can potentially lose value if the realized rate of inflation over the life of the swap is less than the fixed market implied inflation rate (fixed breakeven rate) that the investor agrees to pay at the initiation of the swap. With municipal inflation-indexed securities, the inflation adjustment is integrated into the coupon payment, which is federally tax exempt (and may be state tax exempt). For municipal inflation-indexed securities, there is no adjustment to the principal value. Because municipal inflation-indexed securities are a small component of the municipal bond market, they may be less liquid than conventional municipal bonds.

issuer's continuing ability to make principal and interest payments and may be more volatile than other types of securities. The Fund may also be subject to greater levels of liquidity risk than funds that do not invest in loans. In addition, the loans in which the Fund invests may not be listed on any exchange and a secondary market for such loans may be comparatively illiquid relative to markets for other more liquid fixed income securities. Consequently, transactions in loans may involve greater costs than transactions in more actively traded securities. Restrictions on transfers in loan agreements, a lack of publicly-available information, irregular trading activity and wide bid/ask spreads among other factors, may, in certain circumstances, make loans more difficult to sell at an advantageous time or price than other types of securities or instruments. These factors may result in the Fund being unable to realize full value for the loans and/or may result in the Fund not receiving the proceeds from a sale of a senior loan for an extended period after such sale, each of which could result in losses to the Fund. Some loans may have extended trade settlement periods, including settlement periods of greater than 7 days, which may result in cash not being immediately available to the Fund. If an issuer of a senior loan prepays or redeems the loan prior to maturity, the Fund will have to reinvest the proceeds in other loans or similar instruments that may pay lower interest rates. Because of the risks involved in investing in loans, an investment in the Fund should be considered speculative.

There may be less readily available information about most loans and the underlying borrowers than is the case for many other types of securities, including securities issued in transactions registered under the 1933 Act, or registered under the Exchange Act, and borrowers subject to the periodic reporting requirements of Section 13 of the Exchange Act. Loans may be issued by companies that are not subject to SEC reporting requirements and therefore may not be required to file reports with the SEC or may file reports that are not required to comply with SEC form requirements. In addition, such companies may be subject to a less stringent liability disclosure regime than companies subject to SEC reporting requirements. Loans may not be considered "securities," and purchasers, such as the Fund, therefore may not be entitled to rely on the anti-fraud protections of the federal securities laws. Because there is limited public information available regarding loan investments, the Fund is particularly dependent on the analytical abilities of the Fund's portfolio managers.

The Fund may invest in debt securities issued or guaranteed by agencies, instrumentalities and sponsored enterprises of the U.S. Government. Some U.S. Government securities, such as U.S. Treasury bills, notes and bonds, and mortgage-related securities guaranteed by the GNMA, are supported by the full faith and credit of the United States; others, such as those of the FHLBs or the FHLMC, are supported by the right of the issuer to borrow from the U.S. Treasury; others, such as those of the FNMA, are supported by the discretionary authority of the U.S. Government to purchase the agency's obligations; and still others are supported only by the credit of the agency, instrumentality or corporation. Although legislation has been enacted to support certain government sponsored entities, including the FHLBs, FHLMC and the FNMA, there is no assurance that the obligations of such entities will be satisfied in full, or that such obligations will not decrease in value or default. It is difficult, if not impossible, to predict the future political, regulatory or economic changes that could impact the government sponsored entities and the values of their related securities or obligations. In addition, certain governmental entities, including FNMA and FHLMC, have been subject to regulatory scrutiny regarding their accounting policies and practices and other concerns that may result in legislation, changes in regulatory oversight and/or other consequences that could adversely affect the credit quality, availability or investment character of securities issued by these entities. See "Investment Objective and Policies—Mortgage-Related and Other Asset-Backed Securities" in the Statement of Additional Information.

U.S. Government debt securities generally involve lower levels of credit risk than other types of debt securities of similar maturities, although, as a result, the yields available from U.S. Government debt securities are generally lower than the yields available from such other securities. Like other debt securities, the values of U.S. Government securities change as interest rates fluctuate. Fluctuations in the value of portfolio securities will not affect interest income on existing portfolio securities but will be reflected in the Fund's NAV.

The Fund's investments in debt obligations of foreign (non-U.S.) governments or their sub-divisions, agencies and government sponsored enterprises and obligations of international agencies and supranational entities (together "Foreign Government Securities") can involve a high degree of risk. The foreign governmental entity that controls the repayment of debt may not be able or willing to repay the principal and/or interest when due in accordance with the terms of such debt. A governmental entity's willingness or ability to repay principal and interest due in a timely manner may be affected by, among other factors, its cash flow situation, the extent of its foreign reserves, the availability of sufficient foreign exchange on the date a payment is due, the relative size of the debt service burden to the economy as a whole, the governmental entity's policy towards the International Monetary Fund and the political constraints to which a governmental entity may be subject. Foreign governmental entities also may be dependent on expected disbursements from other governments, multilateral agencies and others abroad to reduce principal and interest arrearages on their debt. The commitment on the part of these governments, agencies and others to make such disbursements may be conditioned on the implementation of economic reforms and/or economic performance and the timely service of such debtor's obligations. Failure to implement such reforms, achieve such levels of economic performance or repay principal or interest when due may result in the cancellation of such third parties' commitments to lend funds to the foreign governmental entity, which may further impair such debtor's ability or willingness to timely service its debts. Consequently, foreign governmental entities may default on their debt. Holders of Foreign Government Securities may be requested to participate in the rescheduling of such debt and to extend further loans to governmental entities. In the event of a default by a governmental entity, there may be few or no effective legal remedies for collecting on such debt. These risks are particularly severe with respect to the Fund's investments in Foreign Government Securities of emerging market countries. See "— Emerging Markets Risk." Among other risks, if the Fund's investments in Foreign Government Securities issued by an emerging market country need to be liquidated quickly, the Fund could sustain significant transaction costs. Also, governments in many emerging market countries participate to a significant degree in their economies and securities markets, which may impair investment and economic growth, and which may in turn diminish the value of the Fund's holdings in emerging market Foreign Government

Securities and the currencies in which they are denominated and/or pay revenues.

There are no direct or indirect government or agency guarantees of payments in pools created by non-governmental issuers. Privately-issued mortgage-related securities are also not subject to the same underwriting requirements for the underlying mortgages that are applicable to those mortgage-related securities that have a government or government-sponsored entity guarantee.

Potential Conflicts of Interest Risk—Allocation of Investment Opportunities

The Investment Manager is involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Fund. The Investment Manager may provide investment management services to other funds and discretionary managed accounts that follow an investment program similar to that of the Fund. Subject to the requirements of the 1940 Act, the Investment Manager intends to engage in such activities and may receive compensation from third parties for their services. The results of the Fund's investment activities may differ from those of the Fund's affiliates, or another account managed by the Fund's affiliates, and it is possible that the Fund could sustain losses during periods in which one or more of the Fund's affiliates and/or other accounts achieve profits on their trading for proprietary or other accounts. The Investment Manager has adopted policies and procedures reasonably designed to allocate investment opportunities on a fair and equitable basis over time.

Legal, tax and regulatory changes could occur and may adversely affect the Fund and its ability to pursue its investment strategies and/or increase the costs of implementing such strategies. New (or revised) laws or regulations may be imposed by the CFTC, the SEC, the IRS, the U.S. Federal Reserve or other banking regulators, other governmental regulatory authorities or self-regulatory organizations that supervise the financial markets that could adversely affect the Fund. In particular, these agencies are implementing a variety of new rules pursuant to financial reform legislation in the United States. The EU (and some other countries) are implementing similar requirements. The Fund also may be adversely affected by changes in the enforcement or interpretation of existing statutes and rules by these governmental regulatory authorities or self-regulatory organizations.

The CFTC and certain futures exchanges have established limits, referred to as "position limits," on the maximum net long or net short positions which any person may hold or control in particular options and futures contracts. The CFTC has proposed position limits for certain swaps. All positions owned or controlled by the same person or entity, even if in different accounts, may be aggregated for purposes of determining whether the applicable position limits have been exceeded. Thus, even if the Fund does not intend to exceed applicable position limits, it is possible that different clients managed by the Investment Manager and their related parties may be aggregated for this purpose. Therefore it is possible that the trading decisions of Investment Manager may have to be modified and that positions held by the Fund may have to be liquidated in order to avoid exceeding such limits. The modification of investment decisions or the elimination of open positions, if it occurs, may adversely affect the performance of the Fund.

Recently adopted rules implementing the credit risk retention requirements of the Dodd-Frank Act for asset-backed securities will require the sponsor of certain securitization vehicles (or a majority owned affiliate of such sponsor) to retain, and to refrain from transferring, selling, conveying to a third party, or hedging 5% of the credit risk in assets transferred, sold, or conveyed through the issuance of the asset-backed securities of such vehicle, subject to certain exceptions. The rules apply to offerings of residential mortgage-backed securities (RMBS) occurring on and after December 24, 2015 and to offerings of other types of asset-backed securities occurring on and after December 24, 2016, subject to certain exceptions. In addition, a refinancing of, or a significant amendment to, a securitization that closed prior to such date may in certain cases result in the application of the rules to a securitization that was previously not subject to the Dodd-Frank risk retention requirements. The impact of the risk retention rules on the securitization markets is uncertain. These requirements may increase the costs to originators, securitizers, and, in certain cases, collateral managers of securitization vehicles in which the Fund may invest, which costs could be passed along to such Fund as an investor in such vehicles. In addition, the costs imposed by the risk retention rules on originators, securitizers and/or collateral managers may result in a reduction of the number of new offerings of asset-backed securities and thus in fewer investment opportunities for the Fund. A reduction in the number of new securitizations could also reduce liquidity in the markets for certain types of financial assets that are typically held by securitization vehicles, which in turn could negatively affect the returns on the Fund's investment in asset-backed securities.

The CFTC has adopted regulations that subject registered investment companies and their investment advisers to regulation by the CFTC if the registered investment company invests more than a prescribed level of its liquidation value in commodity interests, or if the Fund markets itself as providing investment exposure to such instruments. The Investment Manager is registered with the CFTC and as a CPO under the CEA with respect to the Fund a member of the NFA in such capacity. Under CFTC rules, certain mandated disclosure, reporting and recordkeeping obligations will apply to the Investment Manager with respect to the Fund. Compliance with the CFTC's regulatory requirements could increase the Fund's expenses, adversely affecting the Fund's total return.

Rule 144A permits certain qualified institutional buyers, such as the Fund, to trade in privately placed securities that have not been registered for sale under the 1933 Act. Rule 144A securities may be deemed illiquid, although the Fund may determine that certain Rule 144A securities are liquid in accordance with procedures adopted by the Board of Trustees.

The Fund has adopted certain investment limitations designed to limit investment risk and maintain portfolio diversification. These limitations are fundamental and may not be changed without the approval of the holders of a majority of the outstanding Common Shares and Preferred Shares voting together as a single class, and the approval of the holders of a majority of the Preferred Shares voting as a separate class. The Fund may not:

Concentrate its investments in a particular "industry," as that term is used in the Investment Company Act of 1940, as amended, and as interpreted, modified, or otherwise permitted by regulatory authority having jurisdiction, from time to time.

With respect to 75% of the Fund's total assets, purchase the securities of any issuer, except securities issued or guaranteed by the U.S. Government or any of its agencies or instrumentalities or securities issued by other investment companies, if, as a result, (i) more than 5% of the Fund's total assets would be invested in the securities of that issuer, or (ii) the Fund would hold more than 10% of the outstanding voting securities of that issuer. For the purpose of this restriction, each state and each separate political subdivision, agency, authority or instrumentality of such state, each multi-state

agency or authority, and each obligor, if any, is treated as a separate issuer of municipal bonds.

Purchase or sell real estate, although it may purchase securities secured by real estate or interests therein, or securities issued by companies which invest in real estate, or interests therein.

Purchase or sell commodities or commodities contracts or oil, gas or mineral programs. This restriction shall not prohibit the Fund, subject to restrictions described in the Prospectus and elsewhere in this Statement of Additional Information, from purchasing, selling or entering into futures contracts, options on futures contracts, forward contracts, or any interest rate, securities-related or other hedging instrument, including swap agreements and other derivative instruments, subject to compliance with any applicable provisions of the federal securities or commodities laws.

Borrow money or issue any senior security, except to the extent permitted under the Investment Company Act of 1940, as amended, and as interpreted, modified, or otherwise permitted by regulatory authority having jurisdiction, from time to time.

Make loans, except to the extent permitted under the Investment Company Act of 1940, as amended, and as interpreted, modified, or otherwise permitted by regulatory authority having jurisdiction, from time to time.

Act as an underwriter of securities of other issuers, except to the extent that in connection with the disposition of portfolio securities, it may be deemed to be an underwriter under the federal securities laws.

The Fund would be deemed to "concentrate" its investments in a particular industry if it invested more than 25% of its net assets in that industry. The Fund's industry concentration policy does not preclude it from focusing investments in issuers in a group of related industrial sectors (such as different types of utilities).

Additionally, the Fund cannot change its investment objective to seek maximum total return through a combination of current income and capital appreciation without the approval of the holders of a "majority of the outstanding" Common Shares and any Preferred Shares voting together as a single class, and of the holders of a "majority of the outstanding" Preferred Shares voting as a separate class. A "majority of the outstanding" shares (whether voting together as a single class or voting as a separate class) means (i) 67% or more of such shares present at a meeting, if the holders of more than 50% of those shares are present or represented by proxy, or (ii) more than 50% of such shares, whichever is less.

See "Investment Objective and Policies" and "Investment Restrictions" in the Statement of Additional Information for a complete list of the fundamental investment policies of the Fund.

The Fund is subject to asset coverage and other guidelines which are more limiting than the investment restrictions set forth above and other restrictions set forth in the Statement of Additional Information in order to obtain and maintain a rating or ratings from Moody's on the ARPS. See "Description of Capital Structure." See also "Investment Objective and Policies" and "Investment Restrictions" in the Statement of Additional Information for a complete list of the fundamental investment policies of the Fund.

Management Of Investment Portfolio And Capital Structure To Limit Leverage Risk

The Fund may take certain actions if short-term interest rates increase or market conditions otherwise change (or the Fund anticipates such an increase or change) and the Fund's leverage begins (or is expected) to adversely affect Common Shareholders. In order to attempt to offset such a negative impact of leverage on Common Shareholders, the Fund may shorten the average maturity or duration of its investment portfolio (by investing in short-term, high quality securities or implementing certain hedging strategies). The Fund also may attempt to reduce leverage by redeeming or otherwise purchasing preferred shares (subject to any restrictions discussed under "Description of Capital Structure–Preferred Shares Redemption") or by reducing any holdings in other instruments that create leverage. As explained above under "Principal Risks of the Fund—Leverage Risk," the success of any such attempt to limit leverage risk depends on PIMCO's ability to accurately predict interest rate or other market changes. Because of the difficulty of making such predictions, the Fund may not be successful in managing its interest rate exposure in the manner described above.

If market conditions suggest that additional leverage would be beneficial, the Fund may issue additional preferred shares or utilize other forms of leverage, such as reverse repurchase agreements, dollar rolls, credit default swaps and other derivative instruments. See "Investment Objective and Policies—Portfolio Contents" and "Principal Risks of the Fund—Liquidity Risk."

The Fund may (but is not required to) use various investment strategies to seek exposure to foreign currencies, or attempt to hedge exposure to reduce the risk of loss and preserve capital, due to fluctuations in currency exchange rates relative to the U.S. dollar. See "The Fund's Investment Objective and Strategies—Portfolio Contents and Other Information— Foreign Currencies and Related Transactions." The Fund may also purchase credit default swaps for the purpose of hedging the Fund's credit exposure to certain issuers and, thereby, seek to decrease its exposure to credit risk, and it may invest in structured notes or interest rate futures contracts or swap, cap, floor or collar transactions for the purpose of reducing the interest rate sensitivity of the Fund's portfolio and, thereby, seek to decrease the Fund's exposure to interest rate risk. See "Portfolio Contents—Credit Default Swaps," "Portfolio Contents—Structured Notes and Related Instruments" and "Portfolio Contents—Certain Interest Rate Transactions" in this prospectus. Other derivatives strategies and instruments that the Fund may use include without limitation: financial futures contracts; short sales; other types of swap agreements or options thereon; options on financial futures; and options based on either an index or individual debt securities whose prices, PIMCO believes, correlate with the prices of the Fund's investments. Income earned by the Fund from its hedging and related transactions may be subject to one or more special U.S. federal income tax rules that can affect the amount, timing and/or character of distributions to Common Shareholders. For instance, income earned by the Fund from its foreign currency hedging activities, if any, may give rise to ordinary income that, to the extent not offset by losses from such activities,

may be distributed to Common Shareholders and taxable at ordinary income rates. Therefore, any foreign currency hedging activities by the Fund can increase the amount of distributions taxable to Common Shareholders as ordinary income. See "Tax Matters." There is no assurance that these hedging strategies will be available at any time or that PIMCO will determine to use them for the Fund or, if used, that the strategies will be successful. PIMCO may determine not to engage in hedging strategies or to do so only in unusual circumstances or market conditions. In addition, the Fund may be subject to certain restrictions on its use of hedging strategies imposed by guidelines of one or more ratings agencies that may issue ratings on any preferred shares issued by the Fund.

The Board is responsible for the management of the Fund, including supervision of the duties performed by the Investment Manager. There are currently eight Trustees of the Fund, two of whom are treated by the Fund as an "interested person" (as defined in the 1940 Act). The names and business addresses of the Trustees and officers of the Fund and their principal occupations and other affiliations during the past five years are set forth under "Management of the Fund" in the Statement of Additional Information.

PIMCO serves as the investment manager of the Fund. Subject to the supervision of the Board, PIMCO is responsible for managing the investment activities of the Fund and the Fund's business affairs and other administrative matters. PIMCO is located at 650 Newport Center Drive, Newport Beach, CA 92660.

Organized in 1971, PIMCO provides investment management and advisory services to private accounts of institutional and individual clients and to registered investment companies. PIMCO is a majority-owned indirect subsidiary of Allianz SE, a publicly traded European insurance and financial services company. As of March 31, 2018, PIMCO had approximately $1.77 trillion in assets under management.

The following individuals are jointly and primarily responsible for the day-to-day portfolio management of the Fund:

The Statement of Additional Information provides additional information about the portfolio managers' compensation, other accounts managed by the portfolio managers and the portfolio managers' ownership of securities in the Fund.

A control person is a person who owns, either directly or indirectly, beneficially more than 25% of the voting securities of a company. As of March 31, 2018, the Fund did not know of any person or entity who "controlled" the Fund.

The Trustees are responsible generally for overseeing the management of the Fund. The Trustees authorize the Fund to enter into service agreements with the Investment Manager and other service providers in order to provide, and in some cases authorize service providers to procure through other parties, necessary or desirable services on behalf of the Fund. Shareholders are not intended to be third-party beneficiaries of such service agreements.

Neither this prospectus, the Fund's Statement of Additional Information, any contracts filed as exhibits to the Fund's registration statement, nor any other communications or disclosure documents from or on behalf of the Fund creates a contract between any shareholders of the Fund and the Fund, a service provider to the Fund, and/or the Trustees or officers of the Fund. The Trustees may amend this prospectus, the Statement of Additional Information, and any other contracts to which the Fund is a party, and interpret the investment objective(s), policies, restrictions and contractual provisions applicable to the Fund without shareholder input or approval, except in circumstances in which shareholder approval is specifically required by law (such changes to fundamental investment policies) or where a shareholder approval requirement is specifically disclosed in the Fund's prospectus or Statement of Additional Information.

Pursuant to an investment management agreement between the Investment Manager and the Fund (the "Investment Management Agreement"), the Fund has agreed to pay the Investment Manager an annual fee, payable monthly, in an amount equal to 0.650% of the Fund's average daily net assets, including

daily net assets attributable to any preferred shares that may be outstanding. Average daily net assets means an average of all the determinations of the Fund's net assets during a given month at the close of business on each business day during such month.

Pursuant to the Investment Management Agreement, PIMCO shall provide to the Fund investment guidance and policy direction in connection with the management of the Fund, including oral and written research, analysis, advice and statistical and economic data and information. In addition, under the terms of the Investment Management Agreement, subject to the general supervision of the Board of Trustees, PIMCO shall provide or cause to be furnished all supervisory and administrative and other services reasonably necessary for the operation of the Fund under what is essentially an all-in fee structure, including but not limited to the supervision and coordination of matters relating to the operation of the Fund, including any necessary coordination among the custodian, transfer agent, dividend disbursing agent, and recordkeeping agent (including pricing and valuation of the Fund), accountants, attorneys, auction agents and other parties performing services or operational functions for the Fund; the provision of adequate personnel, office space, communications facilities, and other facilities necessary for the effective supervision and administration of the Fund, as well as the services of a sufficient number of persons competent to perform such supervisory and administrative and clerical functions as are necessary for compliance with federal securities laws and other applicable laws; the maintenance of the books and records of the Fund; the preparation of all federal, state, local and foreign tax returns and reports for the Fund; the provision of administrative services to shareholders for the Fund including the maintenance of a shareholder information telephone number, the provision of certain statistical information and performance of the Fund, an internet website (if requested), and maintenance of privacy protection systems and procedures; the preparation and filing of such registration statements and other documents with such authorities as may be required to register and maintain the listing of the shares of the Fund; the taking of other such actions as may be required by applicable law (including establishment and maintenance of a compliance program for the Fund); and the preparation, filing and distribution of proxy materials, periodic reports to shareholders and other regulatory filings.

In addition, under the Investment Management Agreement, PIMCO will procure, at its own expense, the following services, and will bear expenses associated with the following for the Fund: a custodian or custodians for the Fund to provide for the safekeeping of the Fund's assets; a recordkeeping agent to maintain the portfolio accounting records for the Fund; a transfer agent for the Fund; a dividend disbursing agent and/or registrar for the Fund; all audits by the Fund's independent public accountant (except fees to auditors associated with satisfying rating agency requirements for preferred shares or other securities issued by the Fund and other related requirements in the Fund's organizational documents); valuation services; maintaining the Fund's tax records; all costs and/or fees incident to meetings of the Fund's shareholders, the preparation, printing and mailing of the Fund's prospectuses (although the Fund will bear such expenses in connection with the offerings made pursuant to this prospectus as noted below), notices and proxy statements, press releases and reports to its Shareholders, the filing of reports with regulatory bodies, the maintenance of the Fund's existence and qualification to do business, the expense of issuing, redeeming, registering and qualifying for sale, common shares with the federal and state securities authorities, and the expense of qualifying and listing Shares with any securities exchange or other trading system; legal services (except for extraordinary legal expenses); costs of printing certificates representing Shares of the Fund; the Fund's pro rata portion of its fidelity bond and other insurance premiums; and association membership dues.

The Fund (and not PIMCO) will be responsible for certain fees and expenses that are not covered by the unified fee under the Investment Management Agreement. These include fees and expenses, including travel expenses, and fees and expenses of legal counsel retained for their benefit, of Trustees who are not officers, employees, partners, shareholders or members of PIMCO or its subsidiaries or affiliates; the salaries and other compensation or expenses, including travel expenses, of the Fund's executive officers and employees, if any, who are not officers, directors, shareholders, members, partners or employees of PIMCO or its subsidiaries or affiliates; taxes and governmental fees, if any, levied against the Fund; brokerage fees and commissions, and other portfolio transaction expenses incurred by or for the Fund (including, without limitation, fees and expenses of outside legal counsel or third-party consultants retained in connection with reviewing, negotiating and structuring specialized loan and other investments made by the Fund, subject to specific or general authorization by the Fund's Board of Trustees); expenses of the Fund's securities lending (if any), including any securities lending agent fees, as governed by a separate securities lending agreement; costs, including interest expenses, of borrowing money or engaging in other types of leverage financing including, without limitation, through the use by the Fund of reverse repurchase agreements, tender option bonds, bank borrowings and credit facilities; costs, including dividend cost and/or interest expenses and other costs (including, without limitation, offering and related legal costs, fees to brokers, fees to auction agents, fees to transfer agents, fees to ratings agencies and fees to auditors associated with satisfying ratings agency requirements for preferred shares or other securities issued by the Fund and other related requirements in a Fund's organizational documents) associated with the Fund's issuance, offering, redemption and maintenance of preferred shares, commercial paper or other senior securities for the purpose of incurring leverage; fees and expenses of any underlying funds or other pooled vehicles in which the Fund invests; dividend and interest expenses on short positions taken by the Fund; organizational and offering expenses of the Fund, including with respect to share offerings following the Fund's initial offering, such as rights and shelf offerings (including expenses associated with offerings made pursuant to this prospectus), and expenses associated with tender offers and other share repurchases and redemptions; extraordinary expenses, including extraordinary legal expenses as may arise, including expenses incurred in connection with litigation, proceedings, other claims, and the legal obligations of the Fund to indemnify its Trustees, officers, employees, shareholders, distributors, and agents with respect thereto; and expenses of the Fund which are capitalized in accordance with generally accepted accounting principles.

Because the fees received by the Investment Manager are based on the average daily net assets of the Fund (including assets attributable to the ARPS and any other preferred shares that may be outstanding), the Investment Manager has a financial incentive for the Fund to maintain and utilize preferred shares, which may create a conflict of interest between the Investment Manager, on the one hand, and the holders of the Fund's Common Shares, on the other

hand. The fees received by the Investment Manager are not, however, charged on asset attributable to leverage obtained by the Fund other than through preferred shares.

A discussion regarding the basis for the Board's most recent continuation of the Investment Management Agreement is available in the Fund's annual report to shareholders for the fiscal year ended July 31, 2017.

The NAV of the Fund's Common Shares is determined by dividing the total value of the Fund's portfolio investments and other assets, less any liabilities, by the total number of shares outstanding.

On each day that the NYSE is open, Fund shares are ordinarily valued as of the close of regular trading ("NYSE Close"). Information that becomes known to the Fund or its agents after the time as of which NAV has been calculated on a particular day will not generally be used to retroactively adjust the price of a security or the NAV determined earlier that day. The Fund reserves the right to change the time as of which its NAV is calculated if the Fund closes earlier, or as permitted by the SEC.

For purposes of calculating NAV, portfolio securities and other assets for which market quotes are readily available are valued at market value. Market value is generally determined on the basis of official closing prices or the last reported sales prices, or if no sales are reported, based on quotes obtained from established market makers or prices (including evaluated prices) supplied by the Fund's approved pricing services, quotation reporting systems and other third-party sources (together, "Pricing Services"). The Fund will normally use pricing data for domestic equity securities received shortly after the NYSE Close and does not normally take into account trading, clearances or settlements that take place after the NYSE Close. If market value pricing is used, a foreign (non-U.S.) equity security traded on a foreign exchange or on more than one exchange is typically valued using pricing information from the exchange considered by PIMCO to be the primary exchange. If market value pricing is being used, a foreign (non-U.S.) equity security will be valued as of the close of trading on the foreign exchange, or the NYSE Close, if the NYSE Close occurs before the end of trading on the foreign exchange. Domestic and foreign (non-U.S.) fixed income securities, non-exchange traded derivatives, and equity options are normally valued on the basis of quotes obtained from brokers and dealers or Pricing Services using data reflecting the earlier closing of the principal markets for those securities. Prices obtained from Pricing Services may be based on, among other things, information provided by market makers or estimates of market values obtained from yield data relating to investments or securities with similar characteristics. Certain fixed income securities purchased on a delayed-delivery basis are marked to market daily until settlement at the forward settlement date. Exchange-traded options, except equity options, futures and options on futures are valued at the settlement price determined by the relevant exchange. Swap agreements are valued on the basis of bid quotes obtained from brokers and dealers or market-based prices supplied by Pricing Services. With respect to any portion of the Fund's assets that are invested in one or more open-end management investment companies (other than ETFs), the Fund's NAV will be calculated based upon the NAVs of such investments.

If a foreign (non-U.S.) equity security's value has materially changed after the close of the security's primary exchange or principal market but before the NYSE Close, the security may be valued at fair value based on procedures established and approved by the Board. Foreign (non-U.S.) equity securities that do not trade when the NYSE is open are also valued at fair value. With respect to foreign (non-U.S.) equity securities, the Fund may determine the fair value of investments based on information provided by Pricing Services and other third-party vendors, which may recommend fair value or adjustments with reference to other securities, indices or assets. In considering whether fair valuation is required and in determining fair values, the Fund may, among other things, consider significant events (which may be considered to include changes in the value of U.S. securities or securities indices) that occur after the close of the relevant market and before the NYSE Close. The Fund may utilize modeling tools provided by third-party vendors to determine fair values of non-U.S. securities. Foreign (non-U.S.) exchanges may permit trading in foreign (non-U.S.) equity securities on days when the Fund is not open for business, which may result in the Fund's portfolio investments being affected when shareholders are unable to buy or sell shares.

Senior secured floating rate loans for which an active secondary market exists to a reliable degree will be valued at the mean of the last available bid/ask prices in the market for such loans, as provided by a Pricing Service. Senior secured floating rate loans for which an active secondary market does not exist to a reliable degree will be valued at fair value, which is intended to approximate market value. In valuing a senior secured floating rate loan at fair value, the factors considered may include, but are not limited to, the following: (a) the creditworthiness of the borrower and any intermediate participants, (b) the terms of the loan, (c) recent prices in the market for similar loans, if any, and (d) recent prices in the market for instruments of similar quality, rate, period until next interest rate reset and maturity.

Investments valued in currencies other than the U.S. dollar are converted to the U.S. dollar using exchange rates obtained from Pricing Services. As a result, the value of such investments and, in turn, the NAV of the Fund's shares may be affected by changes in the value of currencies in relation to the U.S. dollar. The value of investments traded in markets outside the United States or denominated in currencies other than the U.S. dollar may be affected significantly on a day that the Fund is not open for business. As a result, to the extent that the Fund holds foreign (non-U.S.) investments, the value of those investments may change at times when shareholders are unable to buy or sell shares and the value of such investments will be reflected in the Fund's next calculated NAV.

Investments for which market quotes or market-based valuations are not readily available are valued at fair value as determined in good faith by the Board or persons acting at their direction. The Board has adopted methods for valuing securities and other assets in circumstances where market quotes are not

readily available, and has delegated to PIMCO the responsibility for applying the fair valuation methods. In the event that market quotes or market-based valuations are not readily available, and the security or asset cannot be valued pursuant to a Board approved valuation method, the value of the security or asset will be determined in good faith by the Valuation Oversight Committee of the Board ("Valuation Oversight Committee"), generally based on recommendations provided by PIMCO. Market quotes are considered not readily available in circumstances where there is an absence of current or reliable market-based data (e.g., trade information, bid/ask information, indicative market quotations ("Broker Quotes"), Pricing Services' prices), including where events occur after the close of the relevant market, but prior to the NYSE Close, that materially affect the values of the Fund's securities or assets. In addition, market quotes are considered not readily available when, due to extraordinary circumstances, the exchanges or markets on which the securities trade do not open for trading for the entire day and no other market prices are available. The Board has delegated to PIMCO the responsibility for monitoring significant events that may materially affect the values of the Fund's securities or assets and for determining whether the value of the applicable securities or assets should be reevaluated in light of such significant events.

When the Fund uses fair valuation to determine the value of a portfolio security or other asset for purposes of calculating its NAV, such investments will not be priced on the basis of quotes from the primary market in which they are traded, but rather may be priced by another method that the Board or persons acting at their direction believe reflects fair value. Fair valuation may require subjective determinations about the value of a security. While the Fund's policy is intended to result in a calculation of the Fund's NAV that fairly reflects security values as of the time of pricing, the Fund cannot ensure that fair values determined by the Board or persons acting at their direction would accurately reflect the price that the Fund could obtain for a security if it were to dispose of that security as of the time of pricing (for instance, in a forced or distressed sale). The prices used by the Fund may differ from the value that would be realized if the securities were sold.

The Fund makes regular monthly cash distributions to Common Shareholders at a rate based upon the past and projected net income of the Fund. Subject to applicable law, the Fund may fund a portion of its distributions with gains from the sale of portfolio securities and other sources. Distributions can only be made from net investment income after paying any accrued dividends to holders of the Preferred Shares. The dividend rate that the Fund pays on its Common Shares may vary as portfolio and market conditions change, and will depend on a number of factors, including without limit the amount of the Fund's undistributed net investment income and net short- and long-term capital gains, as well as the costs of any leverage obtained by the Fund (including the amount of the costs and dividend rates on the outstanding ARPS (and any other preferred shares issued by the Fund) and interest or other expenses on any reverse repurchase agreements, credit default swaps, dollar rolls and borrowings). As portfolio and market conditions change, the rate of distributions on the Common Shares and the Fund's dividend policy could change. There can be no assurance that a change in market conditions or other factors will not result in a change in the Fund distribution rate or that the rate will be sustainable in the future. See "Principal Risks of the Fund—Fund Distribution Rates." For a discussion of factors that may cause the Fund's income and capital gains (and therefore the dividend) to vary, see "Principal Risks of the Fund." The Fund generally distributes each year all of its net investment income and net short-term capital gains. In addition, at least annually, the Fund generally distributes net realized long-term capital gains not previously distributed, if any. The net investment income of the Fund consists of all income (other than net short-term and long-term capital gains) less all expenses of the Fund (after it pays accrued dividends on the outstanding Preferred Shares).

To permit the Fund to maintain a more stable monthly distribution, the Fund may distribute less than the entire amount of net investment income earned in a particular period. The undistributed net investment income would be available to supplement future distributions. As a result, the distributions paid by the Fund for any particular monthly period may be more or less than the amount of net investment income actually earned by the Fund during the period. Undistributed net investment income will be additive to the Fund's NAV and, correspondingly, distributions from undistributed net investment income will be deducted from the Fund's NAV.

The tax treatment and characterization of the Fund's distributions may vary significantly from time to time because of the varied nature of the Fund's investments. The Fund may enter into opposite sides of interest rate swap and other derivatives for the principal purpose of generating distributable gains on the one side (characterized as ordinary income for tax purposes) that are not part of the Fund's duration or yield curve management strategies ("paired swap transactions"), and with a substantial possibility that the Fund will experience a corresponding capital loss and decline in NAV with respect to the opposite side transaction (to the extent it does not have corresponding offsetting capital gains). Consequently, Common Shareholders may receive distributions and owe tax on amounts that are effectively a taxable return of the shareholder's investment in the Fund at a time when their investment in the Fund has declined in value, which tax may be at ordinary income. The tax treatment of certain derivatives in which the Fund invests may be unclear and thus subject to recharacterization. Any recharacterization of payments made or received by the Fund pursuant to derivatives potentially could affect the amount, timing or character of Fund distributions. In addition, the tax treatment of such investment strategies may be changed by regulation or otherwise.

To the extent required by the 1940 Act and other applicable laws, absent an exemption, a notice will accompany each monthly distribution with respect to the estimated source (as between net income and gains) of the distribution made. If the Fund estimates that a portion of one of its dividend distributions may be comprised of amounts from sources other than net income in accordance with its policies and good accounting practices, the Fund will notify shareholders of record of the estimated composition of such distribution through a Section 19 Notice. For these purposes, the Fund estimates the source or sources from which a distribution is paid, to the close of the period as of which it is paid, in reference to its internal accounting records and related accounting practices. If, based on such accounting records and practices, it is estimated that a particular distribution does not include capital gains or paid-in surplus or other capital sources, a Section 19 Notice generally would not be issued. It is important to note that differences exist between the Fund's daily internal accounting records and practices, the Fund's financial statements presented in accordance with U.S. GAAP, and recordkeeping practices under income tax regulations. For instance, the Fund's internal accounting records and practices may take into account, among other factors, tax-related characteristics of certain sources of distributions that differ from treatment under U.S. GAAP. Examples of such differences may include, among others, the treatment of paydowns on mortgage-backed securities purchased at a discount and periodic payments under interest rate swap contracts. Accordingly, among other consequences, it is possible that the Fund may not issue a Section 19 Notice in situations where the Fund's financial statements prepared later and in accordance with U.S. GAAP and/or the final tax character of those distributions might later report that the sources of those distributions included capital gains and/or a return of capital.

The tax characterization of the Fund's distributions made in a taxable year cannot finally be determined until at or after the end of such taxable year. As a result, there is a possibility that the Fund may make total distributions during a taxable year in an amount that exceeds the Fund's net investment income and net realized capital gains (as reduced by any capital loss carry-forwards) for the relevant year. For example, the Fund may distribute amounts early in the year that are derived from short-term capital gains, but incur net short-term capital losses later in the year, thereby offsetting short-term capital gains out of which the Fund has already made distributions. In such a situation, the amount by which the Fund's total distributions exceed net investment income and net realized capital gains would generally be treated as a tax-free return of capital up to the amount of a shareholder's tax basis in his or her Common Shares, with any amounts exceeding such basis treated as gain from the sale of Common Shares. In general terms, a return of capital would occur where the Fund distribution (or portion thereof) represents a return of a portion of your investment, rather than net income or capital gains generated from your investment during a particular period. A return of capital distribution is not taxable, but it reduces a shareholder's tax basis in the Common Shares, thus reducing any loss or

increasing any gain on a subsequent taxable disposition by the shareholder of the Common Shares. The Fund will prepare and make available to shareholders detailed tax information with respect to the Fund's distributions annually. See "Tax Matters."

The Fund has adopted a Dividend Reinvestment Plan (the "Plan") which allows Common Shareholders to reinvest Fund distributions in additional Common Shares of the Fund. American Stock Transfer & Trust Company, LLC (the "Plan Agent") serves as agent for Common Shareholders in administering the Plan. It is important to note that participation in the Plan and automatic reinvestment of Fund distributions does not ensure a profit, nor does it protect against losses in a declining market.

Under the Plan, Common Shareholders whose shares are registered with the Plan Agent ("registered shareholders") are automatically enrolled as participants in the Plan and will have all Fund distributions of income, capital gains and returns of capital (together, "distributions") reinvested by the Plan Agent in additional Common Shares of the Fund, unless the Common Shareholder elects to receive cash. Registered shareholders who elect not to participate in the Plan will receive all distributions in cash paid by check and mailed directly to the Common Shareholder of record (or if the shares are held in street or other nominee name, to the nominee) by the Plan Agent.

Participation in the Plan is voluntary. Participants may terminate or resume their enrollment in the Plan at any time without penalty by notifying the Plan Agent online at www.astfinancial.com, by calling (844) 33-PIMCO (844 337-4626), by writing to the Plan Agent, American Stock Transfer & Trust Company, LLC, at P.O. Box 922, Wall Street Station, New York, NY 10269-0560, or, as applicable, by completing and returning the transaction form attached to a Plan statement. A proper notification will be effective immediately and apply to the Fund's next distribution if received by the Plan Agent at least three (3) days prior to the record date for the distribution; otherwise, a notification will be effective shortly following the Fund's next distribution and will apply to the Fund's next succeeding distribution thereafter. If you withdraw from the Plan and so request, the Plan Agent will arrange for the sale of your shares and send you the proceeds, minus brokerage commissions.

For each Fund distribution, the Plan Agent will acquire Common Shares for participants either (i) through receipt of newly issued Common Shares from the Fund ("newly issued shares") or (ii) by purchasing Common Shares of the Fund on the open market ("open market purchases"). If, on a distribution payment date, the NAV is equal to or less than the market price per Common Share plus estimated brokerage commissions (often referred to as a "market premium"), the Plan Agent will invest the distribution amount on behalf of participants in newly issued shares at a price equal to the greater of (i) NAV or (ii) 95% of the market price per Common Share on the payment date. If the NAV is greater than the market price per Common Share plus estimated brokerage commissions (often referred to as a "market discount") on a distribution payment date, the Plan agent will instead attempt to invest the distribution amount through open market purchases. If the Plan Agent is unable to invest the full distribution amount in open market purchases, or if the market discount shifts to a market premium during the purchase period, the Plan Agent will invest any un-invested portion of the distribution in newly issued shares at a price equal to the greater of (i) NAV or (ii) 95% of the market price per share as of the last business day immediately prior to the purchase date (which, in either case, may be a price greater or lesser than the NAV per Common Share on the distribution payment date). No interest will be paid on distributions awaiting reinvestment.

Under the Plan, the market price of Common Shares on a particular date is the last sales price on the exchange where the Common Shares are listed on that date or, if there is no sale on the exchange on that date, the mean between the closing bid and asked quotations for the Common Shares on the exchange on that date. The NAV per Common Share on a particular date is the amount calculated on that date (normally at the close of regular trading on the NYSE) in accordance with the Fund's then current policies.

No brokerage charges are imposed on reinvestments in newly issued shares under the Plan. However, all participants will pay a pro rata share of brokerage commissions incurred by the Plan Agent when it makes open market purchases. There are currently no direct service charges imposed on participants in the Plan, although the Fund reserves the right to amend the Plan to include such charges.

In the case of a registered shareholder such as a broker, bank or other nominee (together, a "nominee") that holds Common Shares for others who are the beneficial owners, the Plan Agent will administer the Plan on the basis of the number of Common Shares certified by the nominee/record shareholder as representing the total amount registered in such shareholder's name and held for the account of beneficial owners who are to participate in the Plan. If your Common Shares are held through a nominee and are not registered with the Plan Agent, neither you nor the nominee will be participants in or have distributions reinvested under the Plan. If you are a beneficial owner of Common Shares and wish to participate in the Plan, and your nominee is unable or unwilling to become a registered shareholder and a Plan participant on your behalf, you may

request that your nominee arrange to have all or a portion of your shares re-registered with the Plan Agent in your name so that you may be enrolled as a participant in the Plan. Please contact your nominee for details or for other possible alternatives. Participants whose shares are registered with the Plan Agent in the name of one nominee firm may not be able to transfer the shares to another firm and continue to participate in the Plan.

Automatically reinvested dividends and distributions are taxed in the same manner as cash dividends and distributions—i.e., automatic reinvestment in additional shares does not relieve Common Shareholders of, or defer the need to pay, any income tax that may be payable (or that is required to be withheld) on Fund dividends and distributions.

The Fund and the Plan Agent reserve the right to amend or terminate the Plan. Additional information about the Plan, as well as a copy of the full Plan itself, may be obtained from the Plan Agent, American Stock Transfer & Trust Company, LLC, at P.O. Box 922, Wall Street Station, New York, NY 10269-0560; telephone number: (844) 33-PIMCO (844-337-4626); website: www.astfinancial.com.

The following is a brief description of the capital structure of the Fund. This description does not purport to be complete and is subject to and qualified in its entirety by reference to the Declaration and the Fund's Bylaws, as amended and restated through the date hereof (the "Bylaws"). The Declaration and Bylaws are each exhibits to the registration statement of which this prospectus is a part.

The Fund is an unincorporated voluntary association with transferable shares of beneficial interest (commonly referred to as a "Massachusetts business trust") established under the laws of the Commonwealth of Massachusetts by the Declaration. The Declaration provides that the Trustees of the Fund may authorize separate classes of shares of beneficial interest. Preferred shares (such as the ARPS) are permitted to be issued in one or more series, with such par value and with such rights as determined by the Board, by action of the Board without the approval of the Common Shareholders.

The following table shows, for each class of authorized securities of the Fund, the amount of (i) shares authorized and (ii) shares outstanding, each as of January 31, 2018.

The Common Shares of the Fund commenced trading on the NYSE in December 2002, under the trading or "ticker" symbol "PTY." As of the close of trading on the NYSE on January 31, 2018, the NAV per Common Share was $15.03, and the closing price per Common Share on the NYSE was $16.43.

Common Shareholders are entitled to share equally in dividends declared by the Board to Common Shareholders and in the net assets of the Fund available for distribution to Common Shareholders after payment of the preferential amounts payable to holders of Preferred Shares and any other outstanding preferred shares of beneficial interest. See "Preferred Shares Dividends" below. All Common Shares of the Fund have equal rights to the payment of dividends and the distribution of assets upon liquidation. Common Shares of the Fund are fully paid and, subject to matters discussed in "Anti-Takeover and Other Provisions in the Declaration of Trust," non-assessable, and have no pre-emptive or conversion rights or rights to cumulative voting, and have no right to cause the Fund to redeem their shares. Upon liquidation of the Fund, after paying or adequately providing for the payment of all liabilities of the Fund and the liquidation preference with respect to the holders of any outstanding preferred shares (including the ARPS), and upon receipt of such releases, indemnities and refunding agreements as they deem necessary for their protection, the Trustees may distribute the remaining assets of the Fund among the Fund's Common Shareholders.

For so long as any ARPS are outstanding, the Fund generally may not declare, pay or set apart for payment any dividend or other distribution (other than a dividend or distribution paid in shares of additional Common Shares or options, warrants or rights to subscribe for or purchase Common Shares or other shares ranking junior to the ARPS as to dividends or upon liquidation) in respect of Common Shares or any other shares of the Fund ranking junior to or on a parity with the ARPS as to dividends or upon liquidation, or call for redemption, redeem, purchase or otherwise acquire for consideration any Common Shares or any other such junior shares (except by conversion into or exchange for shares of beneficial interest of the Fund ranking junior to ARPS as to dividends and upon liquidation) or any such parity shares (except by conversion into or exchange for shares of beneficial interest of the Fund ranking junior to or on a parity with ARPS as to dividends and upon liquidation), unless and only if: (i) immediately after such transaction, the Fund would satisfy Moody's Ratings Agency Preferred Shares Asset Coverage and 1940 Act Preferred Shares Asset Coverage (each as defined and described under "—Rating Agency Guidelines and Asset Coverage"); (ii) full cumulative dividends on the ARPS due on or prior to the date of the transaction have been declared and paid or shall have been declared and sufficient funds for the payment thereof deposited with the auction agent for the ARPS; and (iii) the Fund has redeemed the full number of ARPS required to be redeemed by any provision for mandatory redemption contained in the Bylaws. See "Preferred Shares Redemption." Further, so long as any ARPS are outstanding, the Fund generally may not declare, pay or set apart for payment any dividend or other distribution on any parity shares other than the ARPS unless the Fund contemporaneously declares, pays or sets apart for payment, as the case may be, the same proportionate share of dividends on the ARPS. The Fund expects that similar restrictions would apply to any other classes of preferred shares that the Fund might choose to issue in the future. In addition, if the Fund has outstanding any senior security representing indebtedness, the 1940 Act prohibits the Fund from declaring any dividend or distribution on the Fund's

Common Shares (other than a dividend or distribution paid in shares of additional Common Shares) unless such senior securities representing indebtedness have, at the time of the declaration, asset coverage of at least 300% after deducting the amount of such dividend or distribution. See "Use of Leverage."

Shareholders of each class are entitled to one vote for each share held. Common Shareholders will vote with the holders of any outstanding Preferred Shares or other preferred shares as a single class on each matter submitted to a vote of holders of Common Shares, except as otherwise provided by the Declaration, the Bylaws or applicable law. Except as otherwise provided by the Declaration, the Bylaws or applicable law, holders of Preferred Shares, voting as a separate class, are entitled to elect two of the Fund's Trustees. The remaining Trustees are elected by Common Shareholders and holders of Preferred Shares, voting together as a single class. In the unlikely event that two full years of accrued dividends are unpaid on the Preferred Shares, the holders of all outstanding Preferred Shares, voting as a separate class, will be entitled to elect a majority of the Fund's Trustees until all dividends in arrears have been paid or declared and set apart for payment. The holders of Preferred Shares also have the right to elect a majority of the Fund's Trustees as may be required under the 1940 Act.

The Fund will send unaudited reports at least semiannually and audited financial statements annually to all of its shareholders.

The Fund initially issued ARPS in five series (Series M, Series T, Series W, Series TH and Series F) in February 2003, in the amount of 4,520 shares per series. The ARPS have a par value of $0.00001 and liquidation value of $25,000 per share. The ARPS have various rights determined by action of the Board without the approval of Common Shareholders, most of which are specified in Article 11 of the Bylaws.

In 2008 and 2009, the Fund was effectively required to redeem a portion of its ARPS due to market dislocations that caused the value of the Fund's portfolio securities and related asset coverage to decline. In order to increase and maintain the Fund's asset coverage above the requisite 200% level, in December 2008 and March and April 2009, the Fund redeemed 1,920 shares ($48,000,000) of each series of its outstanding ARPS, in each case at face value (i.e., a total of 9,600 shares ($240,000,000) across all series).

On January 16, 2015, the Fund commenced a voluntary tender offer for up to 100% of its outstanding ARPS at a price equal to 87% of the ARPS' per share liquidation preference of $25,000. On February 27, 2015, the Fund announced the expiration and result of the tender offer. The Fund accepted 3,482 ARPS for payment, representing approximately 27% of its outstanding ARPS, such that on February 27, 2015, the Fund had a total of 9,518 ARPS outstanding (1,884 shares of Series M, 1,770 shares of Series T, 1,847 shares of Series W, 2,033 shares of Series TH and 1,984 shares of Series F) with a total liquidation value of $237,950,000.

Under the 1940 Act, the Fund is permitted to have outstanding more than one series of preferred shares of beneficial interest as long as no single series has priority over another series as to the distribution of assets of the Fund or the payment of dividends. Neither Common Shareholders nor holders of ARPS have preemptive rights to purchase any other preferred shares that might be issued by the Fund.

The ARPS have complete priority over the Common Shares as to distribution of assets. The terms of the ARPS provide that they would ordinarily pay dividends at a rate set at auctions held every seven days, normally payable on the first business day following the end of the rate period, subject to a "maximum applicable rate" calculated as a function of the ARPS' then-current ratings and a reference interest rate as described below. However, the weekly auctions for the ARPS, as well as auctions for similar preferred shares issued by closed-end funds in the U.S., have failed since February 2008, and the dividend rates on the ARPS since that time have been paid at the maximum applicable rate under the Bylaws. In September 2011, Moody's, a ratings agency that provides ratings for the Fund's ARPS, downgraded its rating of the ARPS from "Aaa" to "A2," citing persistently thin asset coverage levels, increased NAV volatility and concerns about secondary market liquidity for some assets supporting rated obligations. In July 2012, Moody's downgraded its rating of the ARPS from "A2" to "A3" pursuant to a revised ratings methodology adopted by Moody's. Also, in May 2014, Moody's upgraded its rating of the Fund's ARPS from A3 to A2, citing changes in the Fund's asset coverage ratio and economic leverage. As shown in the table below, under the Bylaws, the 2011 downgrade resulted in an increase in the multiple used to calculate the maximum applicable rate from 150% to 200%, thereby increasing the dividend rate payable to ARPS holders and increasing the costs to Common Shareholders associated with the Fund's leverage. The Fund expects that the ARPS will continue to pay dividends at the maximum applicable rate for the foreseeable future and cannot predict whether or when the auction markets for the ARPS may resume normal functioning.

As noted, the "maximum applicable rate" for each series of ARPS depends on the credit ratings assigned to such shares (currently by Moody's) and on the duration of the rate period. The maximum applicable rate for any regular rate period (i.e., any rate period other than a non-payment period) will be the applicable percentage of the reference rate. The reference rate is the applicable "AA" Financial Composite Commercial Paper Rate (for a Dividend Period of fewer than 184 days) or the applicable Treasury Index Rate (for a Dividend Period of 184 days or more). The applicable percentage for any Dividend Period is generally determined based on the credit rating assigned to the ARPS by Moody's on the auction date for such period (as set forth in the table below).

The Fund is required to satisfy various asset maintenance requirements with respect to its ARPS under the terms of the Bylaws, which are summarized below.

The Fund is required under the Bylaws to maintain, with respect to the ARPS, as of the last business day of each month in which any Preferred Shares are outstanding, 1940 Act Preferred Shares Asset Coverage (as defined below) of at least 200% with respect to senior securities that are equity securities, including the Preferred Shares. If the Fund fails to maintain 1940 Act Preferred Shares Asset Coverage and such failure is not cured as of the last business day of the following month (the "1940 Act Cure Date"), the Fund will be required under certain circumstances to redeem certain of the Preferred Shares. See "—Preferred Shares Redemption."

The "1940 Act Preferred Shares Asset Coverage" with respect to the Fund's currently outstanding ARPS was equal to the following ratio, as of January 31, 2018

The Fund is required under the Bylaws to satisfy separate asset coverage tests specific to each rating agency (the "Ratings Agency Preferred Shares Asset Coverage").

Satisfaction of Moody's Ratings Agency Preferred Shares Asset Coverage generally requires the Fund to have eligible assets having in the aggregate a discounted value equal to or in excess of a "Preferred Shares Basic Maintenance Amount." Generally, the Preferred Shares Basic Maintenance Amount includes the sum of (a) the aggregate liquidation preference of the Fund's preferred shares then outstanding (including the ARPS) and (b) certain accrued and projected payment obligations of the Fund, including without limit any accrued and projected dividends on its preferred shares then outstanding (including the ARPS).

Article 11 of the Bylaws includes Moody's-specific guidelines for calculating discounted value for purposes of determining whether the Moody's Ratings Agency Preferred Shares Asset Coverage test is satisfied. These guidelines specify discount factors that the Fund must apply to various types of securities in its portfolio for purposes of calculating whether the discounted value of the Fund's eligible assets is at least equal to the Preferred Shares Basic Maintenance Amount (with the level of discount generally becoming greater as the credit quality of a security becomes lower). In addition, under the Moody's guidelines, certain types of securities (including securities in which the Fund may otherwise invest) are not eligible for inclusion in the calculation of the discounted value of the Fund's portfolio. Such ineligible securities may include, for example, certain privately placed debt securities (other than Rule 144A securities) and debt securities of certain non-U.S. issuers. The Moody's guidelines for calculating discounted value do not impose any limitations on the percentage of the Fund's assets that may be invested in ineligible assets, and the amount of ineligible assets included in the Fund's portfolio at any time may vary depending upon the rating, diversification and other characteristics of the Moody's eligible assets included in the portfolio.

In the event the Fund does not timely cure a failure to maintain (a) Moody's Ratings Agency Preferred Shares Asset Coverage or (b) 1940 Act Preferred Shares Asset Coverage, in each case in accordance with the requirements of the rating agency or agencies then rating the ARPS, the Fund will be required to redeem ARPS as described under "—ARPS Redemption—Mandatory Redemption."

In addition to the requirements described above, the rating agency guidelines impose restrictions or limitations on the Fund's use of certain financial instruments or investment techniques that the Fund might otherwise utilize in order to obtain and maintain a rating from Moody's on the ARPS. It is not currently anticipated that these guidelines will materially impede PIMCO from managing the Fund's portfolio in accordance with the Fund's investment objective and policies.

The Fund may, but is not required to, adopt any modifications to the guidelines that may be established by Moody's with respect to their ratings of the ARPS. Failure to adopt any such modifications, however, may result in a reduction in the rating described above or a withdrawal of rating altogether. In addition, any rating agency providing a rating for the ARPS may, at any time, change or withdraw any such rating. The Board may, without shareholder approval, amend, alter or repeal various definitions and related provisions that have been adopted by the Fund pursuant to the rating agency guidelines in the event the Fund receives written confirmation from Moody's (or any substitute rating agency) that any such amendment, alteration or repeal would not impair the rating then assigned by the rating agency to the ARPS.

The ratings of the ARPS are based on current information furnished to Moody's by the Fund or the Investment Manager or information obtained from other sources. The ratings may be changed, suspended or withdrawn as a result of changes in, or the unavailability of, such information. The Common Shares have not been rated by a nationally recognized statistical rating organization. A rating agency's guidelines will apply to the ARPS only so long as the rating agency is rating the shares.

The Fund pays certain fees to Moody's for rating the ARPS. The foregoing description of the rating agency guidelines and asset coverage requirements applicable to the ARPS is intended only as a summary and is qualified in its entirety by reference to the actual terms of Article 11 and other relevant provisions of the Bylaws and Exhibit 1 thereto.

Subject to the rights of holders of any series or class or classes of shares ranking on a parity with the Preferred Shares with respect to the distribution of assets upon liquidation of the Fund, upon a liquidation of the Fund (whether voluntary or involuntary), the holders of Preferred Shares then outstanding would be entitled to receive and to be paid, out of the assets of the Fund available for distribution to its shareholders, before any payment or distribution would be made on the Fund's Common Shares or any other class of shares of the Fund ranking junior in right of payment

upon liquidation to the Preferred Shares, an amount equal to the liquidation preference with respect to such Preferred Shares ($25,000 per share for the ARPS), plus an amount equal to all dividends thereon (whether or not earned or declared by the Fund, but excluding the interest thereon) accumulated but unpaid to (but not including) the date of final distribution in same-day funds in connection with the liquidation of the Fund. If such assets of the Fund are insufficient to make the full liquidation payment on outstanding ARPS and liquidation payments on any other outstanding class or series of preferred shares of the Fund ranking on parity with the ARPS as to payment upon liquidation, then such assets will be distributed among the holders of ARPS and the holders of shares of such other class or series ratably in proportion to the respective preferential amounts to which they are entitled. After the payment to the holders of Preferred Shares of the full preferential amounts provided for as described herein, the holders of Preferred Shares as such would have no right or claim to any of the remaining assets of the Fund. For these purposes, a liquidation of the Fund does not include the sale of all or any portion of the assets of the Fund or the merger, consolidation or statutory share exchange of the Fund into or with any trust or other entity.

As used in this prospectus, unless otherwise noted, the Fund's "net assets" include assets of the Fund attributable to any outstanding Preferred Shares, with no deduction for the liquidation preference of the Preferred Shares. Solely for financial reporting purposes, however, the Fund is required to exclude the liquidation preference of the Preferred Shares from "net assets," so long as the Preferred Shares have redemption features that are not solely within the control of the Fund. For all regulatory and tax purposes, the Fund's Preferred Shares will be treated as stock (rather than indebtedness).

As noted above, the Fund is required under the Bylaws to maintain (a) Moody's Ratings Agency Preferred Shares Asset Coverage and (b) 1940 Act Preferred Shares Asset Coverage. Eligible portfolio securities for the purposes of (a) above will be determined from time to time by the rating agency then rating the then outstanding ARPS. If the Fund fails to maintain such asset coverage amounts and does not timely cure such failure in accordance with the Bylaws, the Fund would be required to redeem all or a portion of the ARPS. This mandatory redemption would take place on a date that the Board specifies out of legally available funds in accordance with the Declaration, the Bylaws and applicable law, at the redemption price of $25,000 per share, plus accumulated but unpaid dividends (whether or not earned or declared) to (but not including) the date fixed for redemption. In determining the number of Preferred Shares required to be redeemed in accordance with the foregoing, the Fund would redeem the lesser of (a) the minimum number of ARPS necessary to satisfy the Ratings Agency Preferred Shares Asset Coverage or 1940 Act Preferred Shares Asset Coverage, as the case may be, and (b) the maximum number of ARPS and any other preferred shares of the Fund subject to redemption or retirement that can be redeemed out of funds expected to be legally available therefor at the time of redemption, and in any case will redeem such Preferred Shares pro rata among the Preferred Shares and any other preferred shares of the Fund subject to redemption or retirement. The mandatory redemption will be limited to the number of ARPS and any other preferred shares necessary to restore the required Ratings Agency Preferred Shares Asset Coverage or 1940 Act Preferred Shares Asset Coverage, as the case may be.

To the extent permitted under the 1940 Act and under Massachusetts law, upon giving notice of redemption, as provided below, the Fund, at its option, may redeem Preferred Shares, in whole or in part, out of funds legally available therefore, at the Optional Redemption Price (as defined below) per share on any dividend payment date, provided that no Preferred Shares may be redeemed at the option of the Fund during (a) the initial rate period with respect to the Preferred Shares or (b) a non-call period to which such shares are subject. "Optional Redemption Price" means $25,000 per Preferred Share plus an amount equal to accumulated but unpaid dividends (whether or not earned or declared) to the date fixed for redemption plus the applicable redemption premium, if any. The Fund has the authority to redeem Preferred Shares for any reason and may redeem all or part of the outstanding Preferred Shares if it anticipates that the Fund's leveraged capital structure will result, for a significant period of time, in a lower rate of return to Common Shareholders than that obtainable if the Common Shares were not so leveraged.

Although the Preferred Shares are subject to redemption under certain circumstances as described above, unlike the shares of an open-end mutual fund, the Preferred Shares may not be redeemed at a shareholder's option at NAV or otherwise.

The Fund may sell Common Shares through underwriters or dealers, directly to one or more purchasers (including existing shareholders in a rights offering), through agents, to or through underwriters or dealers, or through a combination of any such methods of sale. The applicable prospectus supplement will identify any underwriter or agent involved in the offer and sale of the Common Shares, any sales loads, discounts, commissions, fees or other compensation paid to any underwriter, dealer or agent, the offering price, net proceeds and use of proceeds and the terms of any sale.

The distribution of the Common Shares may be effected from time to time in one or more transactions at a fixed price or prices, which may be changed, at prevailing market prices at the time of sale, at prices related to such prevailing market prices, or at negotiated prices.

The Fund may sell the Common Shares directly to, and solicit offers from, institutional investors or others who may be deemed to be underwriters as defined in the 1933 Act for any resales of the securities. In this case, no underwriters or agents would be involved. The Fund may use electronic media, including the Internet, to sell offered securities directly.

In connection with the sale of the Common Shares, underwriters or agents may receive compensation from the Fund in the form of discounts, concessions or commissions. Underwriters may sell Common Shares to or through dealers, and such dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters and/or commissions from the purchasers for whom they may act as agents. Underwriters, dealers and agents that participate in the distribution of the

Common Shares may be deemed to be underwriters under the 1933 Act, and any discounts and commissions they receive from the Fund and any profit realized by them on the resale of the Common Shares may be deemed to be underwriting discounts and commissions under the 1933 Act. Any such underwriter or agent will be identified and any such compensation received from the Fund will be described in the applicable prospectus supplement. The maximum amount of compensation to be received by any Financial Industry Regulatory Authority member or independent broker-dealer will not exceed 8% for the sale of any securities being registered pursuant to Rule 415 under the 1933 Act. The Fund will not pay any compensation to any underwriter or agent in the form of warrants, options, consulting or structuring fees or similar arrangements.

If a prospectus supplement so indicates, the Fund may grant the underwriters an option to purchase additional Common Shares at the public offering price, less the underwriting discounts and commissions, within 45 days from the date of the prospectus supplement, to cover any over-allotments.

Under agreements into which the Fund may enter, underwriters, dealers and agents who participate in the distribution of the Common Shares may be entitled to indemnification by the Fund against certain liabilities, including liabilities under the 1933 Act. Underwriters, dealers and agents may engage in transactions with the Fund, or perform services for the Fund, in the ordinary course of business.

If so indicated in the applicable prospectus supplement, the Fund will, or will authorize underwriters or other persons acting as its agents to, solicit offers by certain institutions to purchase Common Shares from the Fund pursuant to contracts providing for payment and delivery on a future date. Institutions with which such contracts may be made include commercial and savings banks, insurance companies, pension funds, investment companies, educational and charitable institutions and others, but in all cases such institutions must be approved by the Fund. The obligation of any purchaser under any such contract will be subject to the condition that the purchase of the Common Shares shall not at the time of delivery be prohibited under the laws of the jurisdiction to which such purchaser is subject. The underwriters and such other agents will not have any responsibility in respect of the validity or performance of such contracts. Such contracts will be subject only to those conditions set forth in the prospectus supplement, and the prospectus supplement will set forth the commission payable for solicitation of such contracts.

To the extent permitted under the 1940 Act and the rules and regulations promulgated thereunder, the underwriters may from time to time act as brokers or dealers and receive fees in connection with the execution of the Fund's portfolio transactions after the underwriters have ceased to be underwriters and, subject to certain restrictions, each may act as a broker while it is an underwriter.

A prospectus and accompanying prospectus supplement in electronic form may be made available on the websites maintained by underwriters. The underwriters may agree to allocate a number of securities for sale to their online brokerage account holders. Such allocations of securities for Internet distributions will be made on the same basis as other allocations. In addition, securities may be sold by the underwriters to securities dealers who resell securities to online brokerage account holders.

In order to comply with the securities laws of certain states, if applicable, Common Shares offered hereby will be sold in such jurisdictions only through registered or licensed brokers or dealers.

The Fund's Common Shares are listed on the NYSE under the trading or "ticker" symbol "PTY". The Fund's Common Shares commenced trading on the NYSE in December 2002. The Fund cannot predict whether its Common Shares will trade in the future at a premium or discount to NAV. The conduct of any offering and the issuance of additional Common Shares pursuant to any offering may have an adverse effect on prices in the secondary market for the Fund's Common Shares by increasing the number of shares available, which may put downward pressure on the market price for the Common Shares. The NAV of the Fund's Common Shares will be reduced immediately following an offering by the sales load, commissions and offering expenses paid or reimbursed by the Fund in connection with such offering. The completion of an offering may result in an immediate dilution of the NAV per Common Share for all existing Common Shareholders.

The following table sets forth, for each of the periods indicated, the high and low closing market prices of the Fund's Common Shares on the NYSE, the high and low NAV per Common Share and the high and low premium/discount to NAV per Common Share. See "Net Asset Value" for information as to how the Fund's NAV is determined.

1 Such prices reflect inter-dealer prices, without retail mark-up, mark-down or commission and may not represent actual transactions.

The Fund's NAV per Common share at the close of business on January 31, 2018 was $15.03 and the last reported sale price of a Common Share on the NYSE on that day was $16.43, representing a 9.31% premium to such NAV.

The Declaration and the Bylaws include provisions that could limit the ability of other entities or persons to acquire control of the Fund or to convert the Fund to open-end status. The Fund's Trustees are divided into three classes. At each annual meeting of shareholders, the term of one class

will expire and each Trustee elected to that class will hold office until the third annual meeting thereafter. The classification of the Board of Trustees in this manner could delay for an additional year the replacement of a majority of the Board of Trustees. In addition, the Declaration provides that a Trustee may be removed only for cause and only (i) by action of at least seventy-five percent (75%) of the outstanding shares of the classes or series of shares entitled to vote for the election of such Trustee, or (ii) by written instrument, signed by at least seventy-five percent (75%) of the remaining Trustees, specifying the date when such removal shall become effective. Cause for these purposes shall require willful misconduct, dishonesty or fraud on the part of the Trustee in the conduct of his office or such Trustee being convicted of a felony.

As described below, the Declaration grants special approval rights with respect to certain matters to members of the Board who qualify as "Continuing Trustees," which term means a Trustee who either (i) has been a member of the Board for a period of at least thirty-six months (or since the commencement of the Fund's operations, if less than thirty-six months) or (ii) was nominated to serve as a member of the Board of Trustees by a majority of the Continuing Trustees then members of the Board.

The Declaration requires the affirmative vote or consent of at least seventy-five percent (75%) of the Board of Trustees and holders of at least seventy-five percent (75%) of the Fund's shares to authorize certain Fund transactions not in the ordinary course of business, including a merger or consolidation or share exchange, issuance or transfer by the Fund of the Fund's shares having an aggregate fair market value of $1,000,000 or more (except as may be made pursuant to a public offering, the Fund's dividend reinvestment plan or upon exercise of any stock subscription rights), a sale, lease, exchange, mortgage, pledge, transfer or other disposition of Fund assets, having an aggregated fair market value of $1,000,000 or more, or any shareholder proposal regarding specific investment decisions, unless the transaction is authorized by both a majority of the Trustees and seventy-five percent (75%) of the Continuing Trustees (in which case no shareholder authorization would be required by the Declaration, but may be required in certain cases under the 1940 Act). The Declaration also requires the affirmative vote or consent of holders of at least seventy-five percent (75%) of the Fund's shares entitled to vote on the matter to authorize a conversion of the Fund from a closed-end to an open-end investment company, unless the conversion is authorized by both a majority of the Trustees and seventy-five percent (75%) of the Continuing Trustees (in which case shareholders would have only the minimum voting rights required by the 1940 Act with respect to the conversion). Also, the Declaration provides that the Fund may be terminated at any time by vote or consent of at least seventy-five percent (75%) of the Fund's shares or, alternatively, by vote or consent of both a majority of the Trustees and seventy-five percent (75%) of the Continuing Trustees. See "Anti-Takeover and Other Provisions in the Declaration of Trust" in the Statement of Additional Information for a more detailed summary of these provisions.

The Trustees may from time to time grant other voting rights to shareholders with respect to these and other matters in the Bylaws, certain of which are required by the 1940 Act.

The overall effect of these provisions is to render more difficult the accomplishment of a merger or the assumption of control of the Fund by a third party. These provisions also provide, however, the advantage of potentially requiring persons seeking control of the Fund to negotiate with its management regarding the price to be paid and facilitating the continuity of the Fund's investment objective and policies. The provisions of the Declaration and Bylaws described above could have the effect of depriving the Common Shareholders of opportunities to sell their Common Shares at a premium over the then current market price of the Common Shares by discouraging a third party from seeking to obtain control of the Fund in a tender offer or similar transaction. The Board of Trustees of the Fund has considered the foregoing anti-takeover provisions and concluded that they are in the best interests of the Fund and its shareholders, including Common Shareholders.

The foregoing is intended only as a summary and is qualified in its entirety by reference to the full text of the Declaration and the Bylaws, both of which are on file with the SEC.

Under Massachusetts law, shareholders could, in certain circumstances, be held personally liable for the obligations of the Fund. However, the Declaration contains an express disclaimer of shareholder liability for debts or obligations of the Fund and requires that notice of such limited liability be given in each agreement, obligation or instrument entered into or executed by the Fund or the Trustees. The Declaration further provides for indemnification out of the assets and property of the Fund for all loss and expense of any shareholder held personally liable for the obligations of the Fund. Thus, the risk of a shareholder incurring financial loss on account of shareholder liability is limited to circumstances in which the Fund would be unable to meet its obligations. The Fund believes that the likelihood of such circumstances is remote.

The Fund is a closed-end investment company and as such its shareholders will not have the right to cause the Fund to redeem their shares. Instead, the Common Shares will trade in the open market at a price that will be a function of factors relating to the Fund such as dividend levels and stability (which will in turn be affected by Fund expenses, including the dividend costs and other costs of the ARPS and any reverse repurchase agreements, dollar rolls, borrowings and other leverage used by the Fund, levels of dividend and interest payments by the Fund's portfolio holdings, levels of appreciation/depreciation of the Fund's portfolio holdings, regulation affecting the timing and character of the Fund's distributions and other factors), portfolio credit quality, liquidity, call protection, market supply and demand and similar factors relating to the Fund's portfolio holdings. The market price of the Common Shares may also be affected by general market or economic conditions, including market trends affecting securities values generally or values of closed-end fund shares more specifically. Shares of a closed-end investment company may frequently trade at prices lower than NAV. The Fund's Board of Trustees regularly monitors the relationship between the market price and NAV of the Common Shares. If the Common Shares were to trade at a substantial discount to NAV for an extended period of time, the Board of Trustees may consider the repurchase of its Common Shares on the open market or in private transactions, the making of a tender offer for such shares or the conversion of the Fund to an open-

end investment company. The Fund cannot assure you that its Board of Trustees will decide to take or propose any of these actions, or that share repurchases or tender offers will actually reduce any market discount. See "Tax Matters" in the Statement of Additional Information for a discussion of the tax implications of a tender offer by the Fund.

If the Fund were to convert to an open-end company, the Common Shares likely would no longer be listed on the NYSE. In contrast to a closed-end investment company, shareholders of an open-end investment company may require the company to redeem their shares at any time (except in certain circumstances as authorized by or under the 1940 Act) at their NAV, less any redemption charge that is in effect at the time of redemption.

Before deciding whether to take any action to convert the Fund to an open-end investment company, the Board of Trustees would consider all relevant factors, including the extent and duration of the discount, the liquidity of the Fund's portfolio, the impact of any action that might be taken on the Fund or its shareholders, and market considerations. Based on these considerations, even if the Common Shares should trade at a discount, the Board of Trustees may determine that, in the interest of the Fund and its shareholders, no action should be taken. See the Statement of Additional Information under "Repurchase of Common Shares; Conversion to Open-End Fund" for a further discussion of possible action to reduce or eliminate any such discount to NAV.

This section summarizes some of the U.S. federal income tax consequences to U.S. persons of investing in the Fund; the consequences under other tax laws and to non-U.S. shareholders may differ. Shareholders should consult their tax advisors as to the possible application of federal, state, local or non-U.S. income tax laws. Please see the Statement of Additional Information for additional information regarding the tax aspects of investing in the Fund.

The Fund has elected to be treated, and intends each year to qualify and be eligible to be treated, as a regulated investment company under Subchapter M of the Code. A regulated investment company is not subject to U.S. federal income tax at the corporate level on income and gains from investments that are distributed to shareholders. The Fund's failure to qualify as a regulated investment company would result in corporate-level taxation, thereby reducing the return on your investment.

As described under "Use of Leverage" above, if at any time when preferred shares or other senior securities are outstanding the Fund does not meet applicable asset coverage requirements, it will be required to suspend distributions to Common Shareholders until the requisite asset coverage is restored. Any such suspension may cause the Fund to pay a U.S. federal income and excise tax on undistributed income or gains and may, in certain circumstances, prevent the Fund from qualifying for treatment as a regulated investment company. The Fund may repurchase, prepay, or otherwise retire preferred shares or other senior securities, as applicable, in an effort to comply with the distribution requirement applicable to regulated investment companies.

The Fund intends to make monthly distributions of net investment income. A shareholder subject to U.S. federal income tax will generally be subject to tax on Fund distributions. For U.S. federal income tax purposes, Fund distributions will generally be taxable to a shareholder as either ordinary income or capital gains. Fund dividends consisting of distributions of investment income generally are taxable to shareholders as ordinary income. Federal taxes on Fund distributions of capital gains are determined by how long the Fund owned or is deemed to have owned the investments that generated the capital gains, rather than how long a shareholder has owned its shares of the Fund. Distributions of net capital gains (that is, the excess of net long-term capital gains over net short-term capital losses, in each case determined with reference to any loss carryforwards) that are properly reported by the Fund as capital gain dividends generally will be treated as long-term capital gains includible in a shareholder's net capital gains and taxed to individuals at reduced rates. The Fund does not expect a significant portion of their distributions to be treated as long-term capital gains. Distributions of net short-term capital gains in excess of net long-term capital losses generally will be taxable to you as ordinary income.

The Code generally imposes a 3.8% Medicare contribution tax on the "net investment income" of certain individuals, trusts and estates to the extent their income exceeds certain threshold amounts. Net investment income generally includes for this purpose dividends paid by the Fund, including any capital gain dividends and net capital gains recognized on the sale, redemption or exchange of shares of the Fund. Shareholders are advised to consult their tax advisors regarding the possible implications of this additional tax on their investment in the Fund.

The ultimate tax characterization of the Fund's distributions made in a taxable year cannot be determined finally until after the end of that taxable year. As a result, there is a possibility that the Fund may make total distributions during a taxable year in an amount that exceeds the Fund's current and accumulated earnings and profits. In that case, the excess generally would be treated as return of capital and would reduce the shareholders' tax basis in the applicable shares, with any amounts exceeding such basis treated as gain from the sale of such shares. A return of capital is not taxable, but it reduces a shareholder's tax basis in the shares, thus reducing any loss or increasing any gain on a subsequent taxable disposition by the shareholder of the shares.

Fund distributions are taxable to shareholders as described above even if they are paid from income or gains earned by the Fund before a shareholder's investment (and thus were included in the price the shareholder paid).

A shareholder whose distributions are reinvested in Common Shares of the Fund under the Plan will be treated as having received a dividend equal to either (i) if newly issued Common Shares are issued under the Plan, generally the fair market value of the newly issued Common Shares issued to the Common Shareholder or (ii) if reinvestment is made through open-market purchases under the Plan, the amount of cash allocated to the Common Shareholder for the purchase of Common Shares on its behalf in the open market. See "Dividend Reinvestment Plan" above.

Distributions of net short-term capital gain (as reduced by any net long-term capital loss for the taxable year) will be taxable to shareholders as ordinary income. The Fund may report certain dividends as derived from "qualified dividend income," which, when received by a non-corporate shareholder, will be taxed at the rates applicable to net capital gain, provided holding period and other requirements are met at both the Common Shareholder and Fund levels.

The IRS currently requires a regulated investment company that the IRS recognizes as having two or more "classes" of stock for U.S. federal income tax purposes to allocate to each such class proportionate amounts of each type of its income (such as ordinary income and capital gains) based upon the percentage of total dividends distributed to each class for the tax year. Accordingly, as and when applicable, the Fund intends each tax year to allocate capital gain dividends between and among its Common Shares and each series of its Preferred Shares in proportion to the total dividends paid to each class with respect to such tax year. Dividends qualifying and not qualifying for the dividends received deduction or as qualified dividend income will similarly be allocated between and among Common Shares and each series of Preferred Shares, then outstanding.

Any gain resulting from the sale or other disposition of Fund shares that is treated as a sale or exchange for U.S. federal income tax purposes generally will be taxable to shareholders as capital gains for U.S. federal income tax purposes.

In the event that the Fund repurchases a shareholder's Common Shares (as described above), shareholders who offer, and are able to sell all of the shares they hold or are deemed to hold in response to such repurchase offer generally will be treated as having sold their shares and generally will recognize a capital gain or loss. In the case of shareholders who tender or are able to sell fewer than all of their shares, it is possible that any amounts that the shareholder receives in such repurchase will be taxable as a dividend to such shareholder. In addition, there is a risk that shareholders who do not tender any of their shares for repurchase, or whose percentage interest in the Fund otherwise increases as a result of the tender offer, will be treated for U.S. federal income tax purposes as having received a taxable dividend distribution as a result of their proportionate increase in the ownership of the Fund. The Fund's use of cash to repurchase shares could adversely affect its ability to satisfy the distribution requirements for treatment as a regulated investment company. The Fund could also recognize income in connection with its liquidation of portfolio securities to fund share repurchases. Any such income would be taken into account in determining whether such distribution requirements are satisfied.

Income received by the Fund from sources within foreign countries may be subject to withholding and other taxes imposed by such countries, which will reduce the return on those investments. If, at the close of its taxable year, more than 50% of the value of the Fund's total assets consists of securities of foreign corporations, including for this purpose foreign governments, the Fund will be permitted to make an election under the Code that will allow shareholders a deduction or credit for foreign taxes paid by the Fund. If the Fund does not qualify for or chooses not to make such an election, shareholders will not be entitled separately to claim a credit or deduction for U.S. federal income tax purposes with respect to foreign taxes paid by the Fund; in that case the foreign tax will nonetheless reduce the Fund's taxable income. Even if the Fund elects to pass through to its shareholders foreign tax credits or deductions, tax-exempt shareholders and those who invest in the Fund through tax-advantaged accounts such as IRAs will not benefit from any such tax credit or deduction.

The Fund's transactions in foreign currencies, foreign-currency denominated debt obligations, derivatives, short sales, or similar or related transactions could affect the amount, timing, or character of distributions from the Fund, and could increase the amount and accelerate the timing for payment of taxes payable by shareholders. The Fund's investments in certain debt instruments could cause the Fund to recognize taxable income in excess of the cash generated by such investments (which may require the Fund to sell other investments in order to make required distributions, including when it is not advantageous to do so).

The Fund is generally required to withhold and remit to the U.S. Treasury a percentage of the taxable distributions and redemption proceeds, if any, paid to any shareholder who fails to properly furnish the Fund with a correct taxpayer identification number, who has under-reported dividend or interest income, or who fails to certify to the Fund that he, she or it is not subject to such withholding.

Special tax rules apply to investments though defined contribution plans and other tax-advantaged plans. Common Shareholders should consult their tax advisors to determine the suitability of the Fund's Common Shares as an investment through such plans and the precise effect of an investment on their particular tax situation.

The foregoing discussion relates solely to U.S. federal income tax laws. Dividends and distributions also may be subject to state and local taxes. Common Shareholders are urged to consult their tax advisors regarding specific questions as to federal, state, local, and, where applicable, foreign taxes. Foreign investors should consult their tax advisors concerning the tax consequences of ownership of Common Shares of the Fund.

The foregoing is a general and abbreviated summary of the applicable provisions of the Code and related regulations currently in effect. For the complete provisions, reference should be made to the pertinent Code sections and regulations. The Code and regulations are subject to change by legislative or administrative actions.

Please see "Taxation" in the Statement of Additional Information for additional information regarding the tax aspects of investing in Common Shares of the Fund.

The custodian of the assets of the Fund is State Street Bank and Trust Company, 801 Pennsylvania Avenue, Kansas City, Missouri 64105. The custodian performs custodial and fund accounting services as well as sub-administrative services on behalf of the Fund.

American Stock Transfer & Trust Company, LLC, 6201 15th Avenue, Brooklyn, New York 11219, serves as the Fund's transfer agent, registrar, dividend disbursement agent and shareholder servicing agent, as well as agent for the Fund's Dividend Reinvestment Plan.

Deutsche Bank Trust Company Americas, 60 Wall Street, New York, New York 10005, serves as auction agent, transfer agent, registrar, dividend paying agent and redemption agent for the Preferred Shares.

PricewaterhouseCoopers LLP ("PwC"), 1100 Walnut Street, Suite 1300, Kansas City, MO 64106, serves as independent registered public accounting firm for the Fund. PwC provides audit services, tax and other audit related services to the Fund.

Certain legal matters will be passed on for the Fund by Ropes & Gray LLP, Boston, Massachusetts.

The Fund's investments may range in quality from securities rated in the lowest category to securities rated in the highest category (as rated by Moody's, S&P or Fitch or, if unrated, determined by PIMCO to be of comparable quality). The percentage of the Fund's assets invested in securities in a particular rating category will vary. The following terms are generally used to describe the credit quality of fixed income securities:

High Quality Debt Securities are those rated in one of the two highest rating categories (the highest category for commercial paper) or, if unrated, deemed comparable by PIMCO.

Investment Grade Debt Securities are those rated in one of the four highest rating categories, or, if unrated, deemed comparable by PIMCO.

Below Investment Grade, High Yield Securities ("Junk Bonds") are those rated lower than Baa3 by Moody's, BBB- by S&P or Fitch and comparable securities. They are deemed predominately speculative with respect to the issuer's ability to repay principal and interest.

The following is a description of Moody's, S&P's and Fitch's rating categories applicable to fixed income securities.

Long-Term Corporate Obligation Ratings
Moody's long-term obligation ratings are opinions of the relative credit risk of fixed income obligations with an original maturity of one year or more. They address the possibility that a financial obligation will not be honored as promised. Such ratings use Moody's Global Scale and reflect both the likelihood of default and any financial loss suffered in the event of default.

Aaa: Obligations rated Aaa are judged to be of the highest quality, subject to the lowest level of credit risk.

Aa: Obligations rated Aa are judged to be of high quality and are subject to very low credit risk.

A: Obligations rated A are judged to be upper-medium grade and are subject to low credit risk.

Baa: Obligations rated Baa are judged to be medium-grade and subject to moderate credit risk and as such may possess certain speculative characteristics.

Ba: Obligations rated Ba are judged to be speculative and are subject to substantial credit risk.

B: Obligations rated B are considered speculative and are subject to high credit risk.

Caa: Obligations rated Caa are judged to be speculative of poor standing and are subject to very high credit risk.

Ca: Obligations rated Ca are highly speculative and are likely in, or very near, default, with some prospect of recovery of principal and interest.

C: Obligations rated C are the lowest rated and are typically in default, with little prospect for recovery of principal or interest.

Moody's appends numerical modifiers 1, 2, and 3 to each generic rating classification from Aa through Caa. The modifier 1 indicates that the obligation ranks in the higher end of its generic rating category; the modifier 2 indicates a mid-range ranking; and the modifier 3 indicates a ranking in the lower end of that generic rating category. Additionally, a "(hyb)" indicator is appended to all ratings of hybrid securities issued by banks, insurers, finance companies, and securities firms.*

* By their terms, hybrid securities allow for the omission of scheduled dividends, interest, or principal payments, which can potentially result in impairment if such an omission occurs. Hybrid securities may also be subject to contractually allowable write-downs of principal that could result in impairment. Together with the hybrid indicator, the long-term obligation rating assigned to a hybrid security is an expression of the relative credit risk associated with that security.

Moody's assigns provisional ratings to medium-term note (MTN) programs and definitive ratings to the individual debt securities issued from them (referred to as drawdowns or notes).

MTN program ratings are intended to reflect the ratings likely to be assigned to drawdowns issued from the program with the specified priority of claim (e.g. senior or subordinated). To capture the contingent nature of a program rating, Moody's assigns provisional ratings to MTN programs. A provisional rating is denoted by a (P) in front of the rating.

The rating assigned to a drawdown from a rated MTN or bank/deposit note program is definitive in nature, and may differ from the program rating if the drawdown is exposed to additional credit risks besides the issuer's default, such as links to the defaults of other issuers, or has other structural features that warrant a different rating. In some circumstances, no rating may be assigned to a drawdown.

Moody's encourages market participants to contact Moody's Ratings Desks or visit www.moodys.com directly if they have questions regarding ratings for specific notes issued under a medium-term note program. Unrated notes issued under an MTN program may be assigned an NR (not rated) symbol.

Short-Term Ratings
Ratings assigned on Moody's global short-term rating scales are forward-looking opinions of the relative credit risks of financial obligations issued by non-financial corporates, financial institutions, structured finance vehicles, project finance vehicles, and public sector entitities. Short-term ratings are opinions of the ability of issuers to honor short-term financial obligations. Ratings may be assigned to issuers, short-term programs or to individual short-term debt instruments. Such obligations generally have an original maturity not exceeding thirteen months, unless explicitly noted.

Moody's employs the following designations to indicate the relative repayment ability of rated issuers:

P-1: Issuers (or supporting institutions) rated Prime-1 have a superior ability to repay short-term debt obligations.

P-2: Issuers (or supporting institutions) rated Prime-2 have a strong ability to repay short-term debt obligations.

P-3: Issuers (or supporting institutions) rated Prime-3 have an acceptable ability to repay short-term obligations.

NP: Issuers (or supporting institutions) rated Not Prime do not fall within any of the Prime rating categories.

Moody's long-term National Scale Ratings (NSRs) are opinions of the relative creditworthiness of issuers and financial obligations within a particular country. NSRs are not designed to be compared among countries; rather, they address relative credit risk within a given country. Moody's assigns national scale ratings in certain local capital markets in which investors have found the global rating scale provides inadequate differentiation among credits or is inconsistent with a rating scale already in common use in the country. In each specific country, the last two characters of the rating indicate the country in which the issuer is located (e.g., Aaa.br for Brazil).

Aaa.n: Issuers or issues rated Aaa.n demonstrate the strongest creditworthiness relative to other domestic issuers.

Aa.n: Issuers or issues rated Aa.n demonstrate very strong creditworthiness relative to other domestic issuers.

A.n: Issuers or issues rated A.n present above-average creditworthiness relative to other domestic issuers.

Baa.n: Issuers or issues rated Baa.n represent average creditworthiness relative to other domestic issuers.

Ba.n: Issuers or issues rated Ba.n demonstrate below-average creditworthiness relative to other domestic issuers.

B.n: Issuers or issues rated B.n demonstrate weak creditworthiness relative to other domestic issuers.

Caa.n: Issuers or issues rated Caa.n demonstrate very weak creditworthiness relative to other domestic issuers.

Ca.n: Issuers or issues rated Ca.n demonstrate extremely weak creditworthiness relative to other domestic issuers.

C.n: Issuers or issues rated C.n demonstrate the weakest creditworthiness relative to other domestic issuers.

Moody's appends numerical modifiers 1, 2, and 3 to each generic rating classification from Aa through Caa. The modifier 1 indicates that the obligation ranks in the higher end of its generic rating category; the modifier 2 indicates a mid-range ranking; and the modifier 3 indicates a ranking in the lower end of that generic rating category. National scale long-term ratings of D.ar and E.ar may also be applied to Argentine obligations.

National Scale Short-Term Ratings
Moody's short-term NSRs are opinions of the ability of issuers in a given country, relative to other domestic issuers, to repay debt obligations that have an original maturity not exceeding thirteen months. Short-term NSRs in one country should not be compared with short-term NSRs in another country, or with Moody's global ratings.

There are four categories of short-term national scale ratings, generically denoted N-1 through N-4 as defined below.

In each specific country, the first two letters indicate the country in which the issuer is located (e.g., BR-1 through BR-4 for Brazil).

N-1: Issuers rated N-1 have the strongest ability to repay short-term senior unsecured debt obligations relative to other domestic issuers.

N-2: Issuers rated N-2 have an above average ability to repay short-term senior unsecured debt obligations relative to other domestic issuers.

N-3: Issuers rated N-3 have an average ability to repay short-term senior unsecured debt obligations relative to other domestic issuers.

N-4: Issuers rated N-4 have a below average ability to repay short-term senior unsecured debt obligations relative to other domestic issuers.

The short-term rating symbols P-1.za, P-2.za, P-3.za and NP.za are used in South Africa. National scale short-term ratings of AR-5 and AR-6 may also be applied to Argentine obligations.

Short-Term Obligation Ratings
There are three rating categories for short-term municipal obligations that are considered investment grade. These ratings are designated as Municipal Investment Grade (MIG) and are divided into three levels—MIG 1 through MIG 3. In addition, those short-term obligations that are of speculative quality are designated SG, or speculative grade. MIG ratings expire at the maturity of the obligation.

MIG 1: This designation denotes superior credit quality. Excellent protection is afforded by established cash flows, highly reliable liquidity support, or demonstrated broad-based access to the market for refinancing.

MIG 2: This designation denotes strong credit quality. Margins of protection are ample, although not as large as in the preceding group.

MIG 3: This designation denotes acceptable credit quality. Liquidity and cash-flow protection may be narrow, and market access for refinancing is likely to be less well-established.

SG: This designation denotes speculative-grade credit quality. Debt instruments in this category may lack sufficient margins of protection.

Demand Obligation Ratings
In the case of variable rate demand obligations (VRDOs), a two-component rating is assigned: a long- or short-term debt rating and a demand obligation rating. The first element represents Moody's evaluation of risk associated with scheduled principal and interest payments. The second element represents Moody's evaluation of risk associated with the ability to receive purchase price upon demand ("demand feature"). The second element uses a rating from a variation of the MIG scale called the Variable Municipal Investment Grade (VMIG) scale.

VMIG 1: This designation denotes superior credit quality. Excellent protection is afforded by the superior short-term credit strength of the liquidity provider and structural and legal protections that ensure the timely payment of purchase price upon demand.

VMIG 2: This designation denotes strong credit quality. Good protection is afforded by the strong short-term credit strength of the liquidity provider and structural and legal protections that ensure the timely payment of purchase price upon demand.

VMIG 3: This designation denotes acceptable credit quality. Adequate protection is afforded by the satisfactory short-term credit strength of the liquidity provider and structural and legal protections that ensure the timely payment of purchase price upon demand.

SG: This designation denotes speculative-grade credit quality. Demand features rated in this category may be supported by a liquidity provider that does not have an investment grade short-term rating or may lack the structural and/or legal protections necessary to ensure the timely payment of purchase price upon demand.

Long-Term Issue Credit Ratings
Issue credit ratings are based, in varying degrees, on S&P Global Ratings' ("S&P") analysis of the following considerations:

Likelihood of payment—capacity and willingness of the obligor to meet its financial commitment on a financial obligation in accordance with the terms of the obligation;

Protection afforded by, and relative position of, the financial obligation in the event of a bankruptcy, reorganization, or other arrangement under the laws of bankruptcy and other laws affecting creditors' rights.

Issue ratings are an assessment of default risk, but may incorporate an assessment of relative seniority or ultimate recovery in the event of default. Junior obligations are typically rated lower than senior obligations, to reflect the lower priority in bankruptcy, as noted above. (Such differentiation may apply when an entity has both senior and subordinated obligations, secured and unsecured obligations, or operating company and holding company obligations.)

Investment Grade
AAA: An obligation rated 'AAA' has the highest rating assigned by S&P. The obligor's capacity to meet its financial commitment on the obligation is extremely strong.

AA: An obligation rated 'AA' differs from the highest-rated obligations only to a small degree. The obligor's capacity to meet its financial commitment on the obligation is very strong.

A: An obligation rated 'A' is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligations in higher-rated categories. However, the obligor's capacity to meet its financial commitment on the obligation is still strong.

BBB: An obligation rated ‘BBB' exhibits adequate protection parameters. However, adverse economic conditions or changing circumstances are more likely to lead to a weakened capacity of the obligor to meet its financial commitment on the obligation.

Speculative Grade
Obligations rated 'BB', 'B', 'CCC', 'CC', and 'C' are regarded as having significant speculative characteristics. 'BB' indicates the least degree of speculation and 'C' the highest. While such obligations will likely have some quality and protective characteristics, these may be outweighed by large uncertainties or major exposures to adverse conditions.

BB: An obligation rated 'BB' is less vulnerable to nonpayment than other speculative issues. However, it faces major ongoing uncertainties or exposure to adverse business, financial, or economic conditions which could lead to the obligor's inadequate capacity to meet its financial commitment on the obligation.

B: An obligation rated 'B' is more vulnerable to nonpayment than obligations rated ‘BB', but the obligor currently has the capacity to meet its financial commitment on the obligation. Adverse business, financial, or economic conditions will likely impair the obligor's capacity or willingness to meet its financial commitment on the obligation.

CCC: An obligation rated 'CCC' is currently vulnerable to nonpayment, and is dependent upon favorable business, financial, and economic conditions for the obligor to meet its financial commitment on the obligation. In the event of adverse business, financial, or economic conditions, the obligor is not likely to have the capacity to meet its financial commitment on the obligation.

CC: An obligation rated 'CC' is currently highly vulnerable to nonpayment. The ‘CC' rating is used when a default has not yet occurred, but S&P expects default to be a virtual certainty, regardless of the anticipated time to default.

C: An obligation rated ‘C' is currently highly vulnerable to nonpayment, and the obligation is expected to have lower relative seniority or lower ultimate recovery compared to obligations that are rated higher.

D: An obligation rated ‘D' is in default or in breach of an imputed promise. For non-hybrid capital instruments, the ‘D' rating category is used when payments on an obligation are not made on the date due, unless S&P believes that such payments will be made within five business days in the absence of a stated grace period or within the earlier of the stated grace period or 30 calendar days. The ‘D' rating also will be used upon the filing of a bankruptcy petition or the taking of similar action and where default on an obligation is a virtual certainty, for example due to automatic stay provisions. An obligation's rating is lowered to ‘D' if it is subject to a distressed exchange offer.

NR: This indicates that no rating has been requested, that there is insufficient information on which to base a rating, or that S&P does not rate a particular obligation as a matter of policy.

Plus (+) or minus (-): The ratings from ‘AA' to 'CCC' may be modified by the addition of a plus (+) or minus (-) sign to show relative standing within the major rating categories.

Short-Term Issue Credit Ratings
A-1: A short-term obligation rated 'A-1' is rated in the highest category by S&P. The obligor's capacity to meet its financial commitment on the obligation is strong. Within this category, certain obligations are designated with a plus sign (+). This indicates that the obligor's capacity to meet its financial commitment on these obligations is extremely strong.

A-2: A short-term obligation rated 'A-2' is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligations in higher rating categories. However, the obligor's capacity to meet its financial commitment on the obligation is satisfactory.

A-3: A short-term obligation rated 'A-3' exhibits adequate protection parameters. However, adverse economic conditions or changing circumstances are more likely to lead to a weakened capacity of the obligor to meet its financial commitment on the obligation.

B: A short-term obligation rated 'B' is regarded as vulnerable and has significant speculative characteristics. The obligor currently has the capacity to meet its financial commitments; however, it faces major ongoing uncertainties which could lead to the obligor's inadequate capacity to meet its financial commitments.

C: A short-term obligation rated 'C' is currently vulnerable to nonpayment and is dependent upon favorable business, financial, and economic conditions for the obligor to meet its financial commitment on the obligation.

D: A short-term obligation rated ‘D' is in default or in breach of an imputed promise. For non-hybrid capital instruments, the ‘D' rating category is used when payments on an obligation are not made on the date due, unless S&P believes that such payments will be made within any stated grace period. However, any stated grace period longer than five business days will be treated as five business days. The ‘D' rating also will be used upon the filing of a bankruptcy petition or the taking of a similar action and where default on an obligation is a virtual certainty, for example due to automatic stay provisions. An obligation's rating is lowered to ‘D' if it is subject to a distressed exchange offer.

Dual Ratings: Dual ratings may be assigned to debt issues that have a put option or demand feature. The first component of the rating addresses the likelihood of repayment of principal and interest as due, and the second component of the rating addresses only the demand feature. The first component of the rating can relate to either a short-term or long-term transaction and accordingly use either short-term or long-term rating symbols. The second component of the rating relates to the put option and is assigned a short-term rating symbol (for example, ‘AAA/A-1+' or ‘A-1+/A-1'). With U.S. municipal short-term demand debt, the U.S. municipal short-term note rating symbols are used for the first component of the rating (for example, ‘SP-1+/A-1+').

Active Qualifiers
S&P uses the following qualifiers that limit the scope of a rating. The structure of the transaction can require the use of a qualifier such as a 'p' qualifier, which indicates the rating addressed the principal portion of the obligation only. A qualifier appears as a suffix and is part of the rating.

L: Ratings qualified with ‘L' apply only to amounts invested up to federal deposit insurance limits.

p: This suffix is used for issues in which the credit factors, the terms, or both, that determine the likelihood of receipt of payment of principal are different from the credit factors, terms or both that determine the likelihood of receipt of interest on the obligation. The ‘p' suffix indicates that the rating addresses the principal portion of the obligation only and that the interest is not rated.

prelim: Preliminary ratings, with the ‘prelim' suffix, may be assigned to obligors or obligations, including financial programs, in the circumstances described below. Assignment of a final rating is conditional on the receipt by S&P of appropriate documentation. S&P reserves the right not to issue a final rating. Moreover, if a final rating is issued, it may differ from the preliminary rating.

Preliminary ratings may be assigned to obligations, most commonly structured and project finance issues, pending receipt of final documentation and legal opinions.

Preliminary ratings may be assigned to obligations that will likely be issued upon the obligor's emergence from bankruptcy or similar reorganization, based on late-stage reorganization plans, documentation and discussions with the obligor. Preliminary ratings may also be assigned to the obligors. These ratings consider the anticipated general credit quality of the reorganized or post-bankruptcy issuer as well as attributes of the anticipated obligation(s).

Preliminary ratings may be assigned to entities that are being formed or that are in the process of being independently established when, in S&P opinion, documentation is close to final. Preliminary ratings may also be assigned to the obligations of these entities.

Preliminary ratings may be assigned when a previously unrated entity is undergoing a well-formulated restructuring, recapitalization, significant financing or other transformative event, generally at the point that investor or lender commitments are invited. The preliminary rating may be assigned to the entity and to its proposed obligation(s). These preliminary ratings consider the anticipated general credit quality of the obligor, as well as attributes of the anticipated obligation(s), assuming successful completion of the transformative event. Should the transformative event not occur, S&P would likely withdraw these preliminary ratings.

A preliminary recovery rating may be assigned to an obligation that has a preliminary issue credit rating.

t: This symbol indicates termination structures that are designed to honor their contracts to full maturity or, should certain events occur, to terminate and cash settle all their contracts before their final maturity date.

cir: This symbol indicates a Counterparty Instrument Rating (CIR), which is a forward-looking opinion about the creditworthiness of an issuer in a securitization structure with respect to a specific financial obligation to a counterparty (including interest rate swaps, currency swaps, and liquidity facilities). The CIR is determined on an ultimate payment basis; these opinions do not take into account timeliness of payment.

*:This symbol that indicated that the rating was contingent upon S&P receipt of an executed copy of the escrow agreement or closing documentation confirming investments and cash flows. Discontinued use in August 1998.

c: This qualifier was used to provide additional information to investors that the bank may terminate its obligation to purchase tendered bonds if the long-term credit rating of the issuer was lowered to below an investment-grade level and/or the issuer's bonds were deemed taxable. Discontinued use in January 2001.

G: The letter 'G' followed the rating symbol when a fund's portfolio consisted primarily of direct U.S. government securities.

pi: This qualifier was used to indicate ratings that were based on an analysis of an issuer's published financial information, as well as additional information in the public domain. Such ratings did not, however, reflect in-depth meetings with an issuer's management and therefore, could have

been based on less comprehensive information than ratings without a 'pi' suffix. Discontinued use as of December 2014 and as of August 2015 for Lloyd's Syndicate Assessments.

pr: The letters ‘pr' indicate that the rating was provisional. A provisional rating assumed the successful completion of a project financed by the debt being rated and indicates that payment of debt service requirements was largely or entirely dependent upon the successful, timely completion of the project. This rating, however, while addressing credit quality subsequent to completion of the project, made no comment on the likelihood of or the risk of default upon failure of such completion.

q: A ‘q' subscript indicates that the rating is based solely on quantitative analysis of publicly available information. Discontinued use in April 2001.

r: The ‘r' modifier was assigned to securities containing extraordinary risks, particularly market risks, which are not covered in the credit rating. The absence of an ‘r' modifier should not be taken as an indication that an obligation would not exhibit extraordinary non-credit related risks. S&P discontinued the use of the ‘r' modifier for most obligations in June 2000 and for the balance of obligations (mainly structured finance transactions) in November 2002.

Long-Term Credit Ratings
Investment Grade
Rated entities in a number of sectors, including financial and non-financial corporations, sovereigns, insurance companies and certain sectors within public finance, are generally assigned Issuer Default Ratings (IDRs). IDRs are also assigned to certain entities in global infrastructure and project finance. IDRs opine on an entity's relative vulnerability to default on financial obligations. The threshold default risk addressed by the IDR is generally that of the financial obligations whose non-payment would best reflect the uncured failure of that entity. As such, IDRs also address relative vulnerability to bankruptcy, administrative receivership or similar concepts.

In aggregate, IDRs provide an ordinal ranking of issuers based on the agency's view of their relative vulnerability to default, rather than a prediction of a specific percentage likelihood of default.

AAA: Highest credit quality. ‘AAA' ratings denote the lowest expectation of credit risk. They are assigned only in cases of exceptionally strong capacity for payment of financial commitments. This capacity is highly unlikely to be adversely affected by foreseeable events.

AA: Very high credit quality. 'AA' ratings denote expectations of very low credit risk. They indicate very strong capacity for payment of financial commitments. This capacity is not significantly vulnerable to foreseeable events.

A: High credit quality. 'A' ratings denote expectations of low credit risk. The capacity for payment of financial commitments is considered strong. This capacity may, nevertheless, be more vulnerable to adverse business or economic conditions than is the case for higher ratings.

BBB: Good credit quality. 'BBB' ratings indicate that expectations of credit risk are currently low. The capacity for payment of financial commitments is considered adequate, but adverse business or economic conditions are more likely to impair this capacity.

Speculative Grade
BB: Speculative. ‘BB' ratings indicate an elevated vulnerability to credit risk, particularly in the event of adverse changes in business or economic conditions over time; however, business or financial alternatives may be available to allow financial commitments to be met.

B: Highly speculative. ‘B' ratings indicate that material credit risk is present.

Defaulted obligations typically are not assigned 'RD' or ‘D' ratings, but are instead rated in the ‘B' to ‘C' rating categories, depending on their recovery prospects and other relevant characteristics. This approach better aligns obligations that have comparable overall expected loss but varying vulnerability to default and loss.

The modifiers "+" or "-" may be appended to a rating to denote relative status within major rating categories. For example, the rating category 'AA' has three notch-specific rating levels ('AA+'; 'AA'; 'AA-'; each a rating level). Such suffixes are not added to the ‘AAA' obligation rating category, or to corporate finance obligation ratings in the categories below ‘CCC.'

The subscript ‘emr' is appended to a rating to denote embedded market risk that is beyond the scope of the rating. The designation is intended to make clear that the rating solely addresses the counterparty risk of the issuing bank. It is not meant to indicate any limitation in the analysis of the counterparty risk, which in all other respects follows published Fitch criteria for analyzing the issuing financial institution. Fitch does not rate these instruments where the principal is to any degree subject to market risk.

Recovery Ratings
Recovery Ratings are assigned to selected individual securities and obligations, most frequently for individual obligations of corporate finance issuers with Issuer Default Ratings (IDRs) in speculative grade categories.

Among the factors that affect recovery rates for securities are the collateral, the seniority relative to other obligations in the capital structure (where appropriate), and the expected value of the company or underlying collateral in distress.

The Recovery Rating scale is based on the expected relative recovery characteristics of an obligation upon the curing of a default, emergence from insolvency or following the liquidation or termination of the obligor or its associated collateral.

Recovery Ratings are an ordinal scale and do not attempt to precisely predict a given level of recovery. As a guideline in developing the rating assessments, the agency employs broad theoretical recovery bands in its ratings approach based on historical averages and analytical judgment, but actual recoveries for a given security may deviate materially from historical averages.

RR1: Outstanding recovery prospects given default. ‘RR1' rated securities have characteristics consistent with securities historically recovering 91%-100% of current principal and related interest.

RR2: Superior recovery prospects given default. ‘RR2' rated securities have characteristics consistent with securities historically recovering 71%-90% of current principal and related interest.

RR3: Good recovery prospects given default. ‘RR3' rated securities have characteristics consistent with securities historically recovering 51%-70% of current principal and related interest.

RR4: Average recovery prospects given default. ‘RR4' rated securities have characteristics consistent with securities historically recovering 31%-50% of current principal and related interest.

RR5: Below average recovery prospects given default. ‘RR5' rated securities have characteristics consistent with securities historically recovering 11%-30% of current principal and related interest.

RR6: Poor recovery prospects given default. ‘RR6' rated securities have characteristics consistent with securities historically recovering 0%-10% of current principal and related interest.

Short-Term Credit Ratings
A short-term issuer or obligation rating is based in all cases on the short-term vulnerability to default of the rated entity and relates to the capacity to meet financial obligations in accordance with the documentation governing the relevant obligation. Short-term deposit ratings may be adjusted for loss severity. Short-Term Ratings are assigned to obligations whose initial maturity is viewed as "short term" based on market convention. Typically, this means up to 13 months for corporate, sovereign, and structured obligations, and up to 36 months for obligations in U.S. public finance markets.

F1: Highest short-term credit quality. Indicates the strongest intrinsic capacity for timely payment of financial commitments; may have an added "+" to denote any exceptionally strong credit feature.

F2: Good short-term credit quality. Good intrinsic capacity for timely payment of financial commitments.

F3: Fair short-term credit quality. The intrinsic capacity for timely payment of financial commitments is adequate.

B: Speculative short-term credit quality. Minimal capacity for timely payment of financial commitments, plus heightened vulnerability to near term adverse changes in financial and economic conditions.

RD: Restricted default. Indicates an entity that has defaulted on one or more of its financial commitments, although it continues to meet other financial obligations. Typically applicable to entity ratings only.

D: Default. Indicates a broad-based default event for an entity, or the default of a short-term obligation.

The information in this preliminary prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

PIMCO Corporate & Income Opportunity Fund (the “Fund”) has entered into a sales agreement (the “Sales Agreement”) with [ ] (“[ ]”) relating to its common shares of beneficial interest (“Common Shares”) offered by this Prospectus Supplement and the accompanying Prospectus. In accordance with the terms of the Sales Agreement, the Fund may offer and sell up to 14,500,000 of its Common Shares, par value $0.00001 per share, from time to time through [ ] as its agent for the offer and sales of the Common Shares. Under the Investment Company Act of 1940, as amended (the “1940 Act”), the Fund may not sell any Common Shares at a price below the current net asset value of such common shares, exclusive of any distributing commission or discount. The Fund’s investment objective is to seek maximum total return through a combination of current income and capital appreciation.

The Fund’s outstanding Common Shares are listed on the New York Stock Exchange (“NYSE”) under the symbol “PTY,” as will be the Common Shares offered in this Prospectus Supplement and the accompanying Prospectus, subject to notice of issuance. The last reported sale price for the Common Shares on [ ] was $[ ] per share. The net asset value of the Common Shares at the close of business on [ ] was $[ ] per share.

[ ] will be entitled to compensation of up to [ ]% of the gross proceeds with respect to sales of the Common Shares actually effected by [ ] under the Sales Agreement. In connection with the sale of the Common Shares on our behalf, [ ] may be deemed to be an “underwriter” within the meaning of the 1933 Act and the compensation of [ ] may be deemed to be underwriting commissions or discounts.

[ ] is not required to sell any specific number or dollar amount of common shares, but will use its commercially reasonable efforts to sell the Common Shares offered by this Prospectus Supplement and the accompanying Prospectus. There is no arrangement for Common Shares to be received in an escrow, trust or similar arrangement.

You should review the information set forth under “Principal Risks of the Fund” on page 54 of the accompanying Prospectus before investing in the Common Shares.

Neither the U.S. Securities and Exchange Commission (“SEC”) nor the U.S. Commodity Futures Trading Commission (“CFTC”) have approved or disapproved of these securities or determined that this Prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

You should read this Prospectus Supplement and the accompanying Prospectus before deciding whether to invest in the Common Shares and retain them for future reference. The Prospectus Supplement and the accompanying Prospectus contain important information about the Fund. Material that has been incorporated by reference and other information about us can be obtained from us by calling toll free (844) 33-PIMCO (844-337-4626) or by writing to the Fund at c/o Pacific Investment Management Company LLC, 1633 Broadway, New York, New York 10019. You may also obtain a copy of the Statement of Additional Information (and other information regarding the Fund) from the Securities and Exchange Commission’s (the “SEC”) Public Reference Room in Washington, D.C. by calling (202) 551-8090. The SEC charges a fee for copies. The Fund’s Statement of Additional Information and most recent annual and semiannual reports are available, free of charge, on the Fund’s website (http://www.pimco.com). You can obtain the same information, free of charge, from the SEC’s website (http://www.sec.gov).

You should rely only on the information contained or incorporated by reference in this Prospectus Supplement and the accompanying Prospectus. The Fund has not, and [ ] has not, authorized anyone to provide you with inconsistent information. If anyone provides you with inconsistent information, you should not assume that the Fund or [ ] has authorized or verified it. The Fund is not, and [ ] is not, making an offer of these securities in any state where the offer is not permitted. You should not assume that the information contained in this Prospectus Supplement and the accompanying Prospectus is accurate as of any date other than the date on the front hereof or thereof. The Fund’s business, financial condition, results of operations and prospects may have changed since that date.

This document has two parts. The first part is this Prospectus Supplement, which describes the terms of this offering of Common Shares and also adds to and updates information contained in the accompanying Prospectus. The second part is the accompanying Prospectus, which gives more general information and disclosure. To the extent the information contained in this Prospectus Supplement differs from or is additional to the information contained in the accompanying Prospectus, you should rely only on the information contained in this Prospectus Supplement. You should read this Prospectus Supplement and the accompanying Prospectus before investing in the Common Shares.

This Prospectus Supplement, the accompanying Prospectus and the Fund’s Statement of Additional Information, including documents incorporated by reference, contain “forward-looking statements.” Forward-looking statements can be identified by the words “may,” “will,” “intend,” “expect,” “estimate,” “continue,” “plan,” “anticipate,” and similar terms and the negative of such terms. By their nature, all forward-looking statements involve risks and uncertainties, and actual results could differ materially from those contemplated by the forward-looking statements. Several factors that could materially affect the Fund’s actual results are the performance of the portfolio of securities held by the Fund, the conditions in the U.S. and international financial and other markets, the price at which the Fund’s Common Shares will trade in the public markets and other factors discussed in the Fund’s periodic filings with the SEC.

Although the Fund believes that the expectations expressed in our forward-looking statements are reasonable, actual results could differ materially from those expressed or implied in our forward-looking statements. The Fund’s future financial condition and results of operations, as well as any forward-looking statements, are subject to change and are subject to inherent risks and uncertainties, such as those disclosed in the “Principal Risks of the Fund” section of the accompanying Prospectus. You are cautioned not to place undue reliance on these forward-looking statements. All forward-looking statements contained or incorporated by reference in this Prospectus Supplement or the accompanying Prospectus are made as of the date of this Prospectus Supplement or the accompanying Prospectus, as the case may be. Except for the Fund’s ongoing obligations under the federal securities laws, the Fund does not intend, and the Fund undertakes no obligation, to update any forward-looking statement. The forward-looking statements contained in this Prospectus Supplement, the accompanying Prospectus and the Fund’s Statement of Additional Information are excluded from the safe harbor protection provided by section 27A of the 1933 Act.

Currently known risk factors that could cause actual results to differ materially from the Fund’s expectations include, but are not limited to, the factors described in the “Principal Risks of the Fund” section of the accompanying Prospectus. The Fund urges you to review carefully those sections for a more detailed discussion of the risks of an investment in our securities.

This is only a summary. This summary may not contain all of the information that you should consider before investing in the Fund’s common shares of beneficial interest (the “Common Shares”). You should review the more detailed information contained in this Prospectus Supplement and in the accompanying Prospectus and in the Statement of Additional Information, especially the information set forth under the heading “Principal Risks of the Fund” beginning on page 54 of the accompanying Prospectus

PIMCO Corporate & Income Opportunity Fund (the “Fund”) is a diversified, closed-end management investment company that commenced operations on December 27, 2002, following the initial public offering of its Common Shares.

The Common Shares are listed on the New York Stock Exchange (“NYSE”) under the symbol “PTY.” As of [ ], the net assets of the Fund attributable to Common Shares were $[ ] and the Fund had outstanding [ ] Common Shares and 9,518 auction rate preferred shares of beneficial interest (“ARPS” and, together with any other preferred shares issued by the Fund, “Preferred Shares”). The last reported sale price of the Common Shares, as reported by the NYSE on [ ], was $[ ] per Common Share. The net asset value of the Common Shares at the close of business on [ ], was $[ ] per Common Share. See “Description of Capital Structure” in the accompanying Prospectus.

The Fund’s investment objective is to seek maximum total return through a combination of current income and capital appreciation.

The Fund seeks to achieve its investment objective by utilizing a dynamic asset allocation strategy among multiple fixed-income sectors in the global credit markets, including corporate debt (including, among other things, fixed-, variable- and floating-rate bonds, bank loans, convertible securities and stressed debt securities issued by U.S. or foreign (non-U.S.) corporations or other business entities, including emerging market issuers), mortgage-related and other asset-backed securities, government and sovereign debt, taxable municipal bonds and other fixed-, variable- and floating-rate income-producing securities of U.S. and foreign issuers, including emerging market issuers. The Fund may invest in investment grade debt securities and below investment grade debt securities (commonly referred to as “high yield” securities or “junk bonds”), including securities of stressed issuers. The types of securities and instruments in which the Fund may invest are summarized under “Portfolio Contents” in the accompanying Prospectus.

Investment in the Fund’s Common Shares involves substantial risks arising from, among other strategies, the Fund’s ability to invest in debt instruments that are, at the time of purchase, rated below investment grade (below Baa3 by Moody’s Investors Service, Inc. (“Moody’s”) or below BBB- by either S&P Global Ratings, a division of The McGraw-Hill Company, Inc. (“S&P”) or Fitch, Inc. (“Fitch”)) or unrated but determined by PIMCO to be of comparable quality, the Fund’s exposure to foreign and emerging markets securities and currencies and to mortgage-related and other asset-backed securities, and the Fund’s use of leverage. Debt securities of below investment grade quality are regarded as having predominantly speculative characteristics with respect to capacity to pay interest and to repay principal, and are commonly referred to as “high yield” securities or “junk bonds.” The Fund’s exposure to foreign securities and currencies, and particularly to emerging markets securities and currencies, involves special risks, including foreign currency risk and the risk that the securities may decline in response to unfavorable

political and legal developments, unreliable or untimely information or economic and financial instability. Mortgage-related and other asset-backed securities are subject to extension and prepayment risk and often have complicated structures that make them difficult to value. Because of the risks associated with investing in high yield securities, foreign and emerging market securities (and related exposure to foreign currencies) and mortgage-related and other asset-backed securities, and using leverage, an investment in the Fund should be considered speculative. Before investing in the Common Shares, you should read the discussion of the principal risks of investing in the Fund in “Principal Risks of the Fund” in the accompanying Prospectus. Certain of these risks are summarized in “Prospectus Summary—Principal Risks of the Fund” in the accompanying Prospectus. The Fund cannot assure you that it will achieve its investment objective, and you could lose all of your investment in the Fund.

Pacific Investment Management Company LLC (“PIMCO” or the “Investment Manager”) serves as the investment manager of the Fund. Subject to the supervision of the Board of Trustees of the Fund (the “Board”) PIMCO is responsible for managing the investment activities of the Fund and the Fund’s business affairs and other administrative matters. The Investment Manager receives an annual fee from the Fund, payable monthly, in an amount equal to 0.65% of the Fund’s average daily net assets, including daily net assets attributable to any preferred shares that may be outstanding. Average daily net assets means an average of all the determinations of the Fund’s net assets (including net assets attributable to preferred shares) during a given month at the close of business on each business day during such month.

PIMCO is located at 650 Newport Center Drive, Newport Beach, CA, 92660. Organized in 1971, PIMCO provides investment management and advisory services to private accounts of institutional and individual clients and to registered investment companies. PIMCO is a majority-owned indirect subsidiary of Allianz SE, a publicly traded European insurance and financial services company. As of [ ], PIMCO had approximately $[ ] trillion in assets under management.

The Fund and the Investment Manager have entered into the Sales Agreement with [ ] relating to the Common Shares offered by this Prospectus Supplement and the accompanying Prospectus. In accordance with the terms of the Sales Agreement, the Fund may offer and sell up to 14,500,000 Common Shares, par value $0.00001, through [ ] as its agent for the offer and sale of the Common Shares.

The Fund’s outstanding Common Shares are listed on the NYSE under the symbol “PTY,” as will be the Common Shares offered in this Prospectus Supplement and the accompanying Prospectus, subject to notice of issuance. The last reported sale price for the Common Shares on [ ] was $[ ]per share.

Sales of the Common Shares, if any, under this Prospectus Supplement and the accompanying Prospectus may be made in negotiated transactions or transactions that are deemed to be “at the market” as defined in Rule 415 under the 1933 Act, including sales made directly on the NYSE or sales made to or through a market maker other than on an exchange. See “Plan of Distribution” in this Prospectus Supplement. The Common Shares may not be sold through agents, underwriters or dealers without delivery or deemed delivery of a prospectus and a prospectus supplement describing the method and terms of the offering of the Fund’s securities. Under the 1940 Act, the Fund may not sell any Common Shares at a price below the current net asset value of such Common Shares, exclusive of any distributing commission or discount.

The net proceeds of this offering will be invested in accordance with the Fund’s investment objective and policies as set forth in the accompanying Prospectus. It is currently anticipated that the Fund will be able to invest substantially all of the net proceeds of this offering in accordance with its investment objective and policies within approximately 30 days of receipt by the Fund, depending on the amount and timing of proceeds available to the Fund as well as the availability of investments consistent with the Fund’s investment objective and policies, and except to the extent proceeds are held in cash to pay dividends or expenses or for temporary defensive purposes. See “Use of Proceeds” in this Prospectus Supplement.

The following table is intended to assist investors in understanding the fees and expenses (annualized) that an investor in Common Shares of the Fund would bear, directly or indirectly, as a result of an offering. The table reflects the use of leverage attributable to the Fund’s outstanding Preferred Shares and reverse repurchase agreements in an amount equal to [ ]% of the Fund’s total managed assets (including assets attributable to such leverage), which reflects approximately the percentage of the Fund’s total managed assets attributable to such leverage as of [ ], and shows Fund expenses as a percentage of net assets attributable to Common Shares. The percentage above does not reflect the Fund’s use of other forms of economic leverage, such as credit default swaps or other derivative instruments. The table and example below are based on the Fund’s capital structure as of [ ]. The extent of the Fund’s assets attributable to leverage following an offering, and the Fund’s associated expenses, are likely to vary (perhaps significantly) from these assumptions.

The following example illustrates the expenses that you would pay on a $1,000 investment in Common Shares of the Fund (including the total sales load or commission of $[ ] and the other estimated costs of this offering to be borne by the Common Shareholders of $[ ]), assuming (1) that the Fund’s net assets do not increase or decrease, (2) that the Fund incurs total annual expenses of [ ]% of net assets attributable to Common Shares in years 1 through 10 (assuming outstanding Preferred Shares and reverse repurchase agreements representing [ ]% of the Fund’s total managed assets) and (3) a 5% annual return(1):

The following table sets forth for the quarters indicated, the high and low sale prices on the New York Stock Exchange per share of the Common Shares and the NAV and the premium or discount from NAV per share at which the Common Shares were trading, expressed as a percentage of NAV, at each of the high and low sale prices provided.

Certain legal matters will be passed on for the Fund by Ropes & Gray LLP, Boston, Massachusetts.

This Prospectus Supplement and the accompanying Prospectus constitute part of a Registration Statement filed by the Fund with the SEC under the 1933 Act and the 1940 Act. This Prospectus Supplement and the accompanying Prospectus omit certain of the information contained in the Registration Statement, and reference is hereby made to the Registration Statement and related exhibits for further information with respect to the Fund and the Common Shares offered hereby. Any statements contained herein concerning the provisions of any document are not necessarily complete, and, in each instance, reference is made to the copy of such document filed as an exhibit to the Registration Statement or otherwise filed with the SEC. Each such statement is qualified in its entirety by such reference. The complete Registration Statement may be obtained from the SEC upon payment of the fee prescribed by its rules and regulations or free of charge through the SEC’s website (http://www.sec.gov).

Until [ ], 2017 (25 days after the date of this Prospectus Supplement), all dealers that buy, sell or trade the Common Shares, whether or not participating in this offering, may be required to deliver a prospectus. This is in addition to the dealers’ obligation to deliver a prospectus when acting as underwriters.

The information in this Statement of Additional Information is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This Statement of Additional Information, which is not a prospectus, is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state or jurisdiction where the offer or sale is not permitted.

PIMCO Corporate & Income Opportunity Fund (the “Fund”) is a diversified, closed-end management investment company.

Pacific Investment Management Company LLC (“PIMCO” or the “Investment Manager”), 650 Newport Center Drive, Newport Beach, California 92660, is the investment manager to the Fund.

This Statement of Additional Information relating to the common shares of the Fund (the “Common Shares”) is not a prospectus, and should be read in conjunction with the Fund’s prospectus relating thereto dated June [ ], 2018 (the “Prospectus”) and any related prospectus supplement. This Statement of Additional Information does not include all information that a prospective investor should consider before purchasing Common Shares, and investors should obtain and read the Prospectus and any related prospectus supplement prior to purchasing such shares. A copy of the Prospectus and any related prospectus supplement may be obtained without charge by calling 844-337-4626. You may also obtain a copy of the Prospectus or any related prospectus supplement on the Web site of the Securities and Exchange Commission (the “SEC”) at http://www.sec.gov.

Capitalized terms used but not defined in this Statement of Additional Information have the meanings ascribed to them in the Prospectus and any related prospectus supplement.

The Fund commenced operations on December 27, 2002, following the initial public offering of its common shares. Effective February 1, 2012, the Fund changed its name from PIMCO Corporate Opportunity Fund to its current name, PIMCO Corporate & Income Opportunity Fund. The Fund was organized as a Massachusetts business trust on September 13, 2002. Prior to commencing operations on December 27, 2002, the Fund had no operations other than matters relating to its organization and registration as a diversified, closed-end management company registered under the Investment Company Act of 1940, as amended (the “1940 Act”).

The investment objective and general investment policies of the Fund are described in the Prospectus. Additional information concerning the characteristics of certain of the Fund’s investments is set forth below. Unless a strategy or policy described below is specifically prohibited by the investment restrictions listed in the Prospectus, by the investment restrictions under “Investment Restrictions” in this Statement of Additional Information, or by applicable law, the Fund may engage in each of the practices described below. However, the Fund is not required to engage in any particular transaction or purchase any particular type of securities or investment even if to do so might benefit the Fund. Unless otherwise stated herein, all investment policies of the Fund may be changed by the Board of Trustees (the “Board’) without shareholder approval. In addition, the Fund may be subject to restrictions on its ability to utilize certain investments or investment techniques. Unless otherwise stated herein, these additional restrictions may be changed with the consent of the Board but without approval by or notice to shareholders.

High Yield Securities (“Junk Bonds”) and Securities of Distressed Companies

The Fund may invest in debt instruments that are, at the time of purchase, rated below investment grade, or unrated but determined by PIMCO to be of comparable quality. The Fund will not normally invest more than 20% of its total assets in debt instruments, other than mortgage-related and other asset-backed securities, that are, at the time of purchase, rated CCC or lower by S&P Global Ratings (“S&P”) and Fitch, Inc. (“Fitch”) and Caa1 or lower by Moody’s Investors Services Inc. (“Moody’s”), or that are unrated but determined by PIMCO to be of comparable quality to securities so rated. The Fund may invest without limit in mortgage-related and other asset-backed securities regardless of rating (i.e., of any credit quality). Subject to this 20% restriction, the Fund may invest in issuers of any credit quality (including bonds in the lowest ratings categories) if PIMCO determines that the particular obligation is undervalued or offers an attractive yield relative to its risk profile. The Fund may also invest up to 5% of its total assets in defaulted bonds when PIMCO believes that the issuer’s potential revenues and prospects for recovery are favorable, except that the Fund may invest in mortgage-related and other asset-backed securities without regard to this limit, subject to the Fund’s other investment policies. A description of the ratings categories used is set forth in Appendix A to the Prospectus.

A security is considered to be below “investment grade” quality if it is either (1) not rated in one of the four highest rating categories by one of the nationally recognized statistical rating organizations (“NRSROs”) (i.e., rated Ba or below by Moody’s, BB or below by S&P or BB or below by Fitch) or (2) if unrated, determined by PIMCO to be of comparable quality to obligations so rated.

Investments in securities rated below investment grade are described as “speculative” by Moody’s, S&P and Fitch, and are commonly referred to as “high yield” securities or “junk bonds.” Additional information about Moody’s, S&P’s and Fitch’s securities ratings is included in Appendix A to the Prospectus.

Investors should consider the risks associated with high yield securities and debt securities of distressed companies before investing in the Fund. Investment in lower rated corporate debt securities and securities of distressed companies generally provides greater income and increased opportunity for capital appreciation than investments in higher quality securities, but it also typically entails greater price volatility and principal and income risk. Securities of distressed companies include both debt and equity securities. High yield securities and debt securities of distressed companies are regarded as predominantly speculative with respect to the issuer’s continuing ability to meet principal and interest payments. Issuers of high yield and distressed company securities may be involved in restructurings or bankruptcy proceedings that may not be successful. Analysis of the creditworthiness of issuers of debt securities that are high yield or debt securities of distressed companies may be more complex than for issuers of higher quality debt.

The Fund’s investments in high yield securities, debt securities of distressed companies and unrated securities of similar credit quality may subject it to greater levels of credit risk, call risk and liquidity risk than funds that do not invest in such securities. These securities are considered predominantly speculative with respect to an issuer’s continuing ability to make principal and interest payments, and may be more volatile than other types of securities. An economic downturn or individual corporate developments could adversely affect the market for these securities and reduce the Fund’s ability to sell these securities at an advantageous time or price.

A projection of an economic downturn, for example, could cause a decline in prices of high yield securities and debt securities of distressed companies because the advent of a recession could lessen the ability of a highly leveraged company to make principal and interest payments on its debt securities, and a high yield security may lose significant market value before a default occurs. If an issuer of high yield or distressed company securities defaults, in addition to risking payment of all or a portion of interest and principal, the Fund may incur additional expenses to seek recovery of their respective investments. In the case of securities structured as zero-coupon or pay-in-kind securities, their market prices are affected to a greater extent by interest rate changes, and therefore tend to be more volatile than securities which pay interest periodically and in cash.

Issuers of high yield securities and securities of distressed companies may have the right to “call” or redeem the issue prior to maturity, which may result in the Fund having to reinvest the proceeds in other high yield securities that may pay lower interest rates. The Fund may also be subject to greater levels of liquidity risk than funds that do not invest in these securities. In addition, the high yield securities and securities of distressed companies in which the Fund invests may not be listed on any exchange and a secondary market for such securities may be comparatively illiquid relative to markets for other more liquid fixed income securities. Consequently, transactions in high yield securities and distressed company securities may involve greater costs than transactions in more actively traded securities, which could adversely affect the price at which the Fund could sell a high yield or distressed company security, and could adversely affect the daily net asset value of the shares. A lack of publicly-available information, irregular trading activity and wide bid/ask spreads among other factors, may, in certain circumstances, make high yield and distressed company debt difficult to sell at an advantageous time or price than other types of securities or instruments. These factors may result in the Fund being unable to realize full value for these securities and/or may

result in the Fund not receiving the proceeds from a sale of a high yield or distressed company security for an extended period after such sale, each of which could result in losses to the Fund. Because of the risks involved in investing in high yield securities and securities of distressed companies, an investment in the Fund should be considered speculative.

Analysis of the creditworthiness of issuers of high yield securities and distressed company securities may be more complex than for issuers of higher quality debt securities, and achievement of the Fund’s investment objective may, to the extent of its investments in high yield and distressed company securities, depend more heavily on PIMCO’s creditworthiness analysis than would be the case if the Fund were investing in higher quality securities.

High yield securities structured as “zero-coupon” bonds or “payment-in-kind” securities (“PIKs”) tend to be especially volatile as they are particularly sensitive to downward pricing pressures from rising interest rates or widening spreads and may require the Fund to make taxable distributions of income greater than the total amount of cash interest the Fund has actually received. PIMCO seeks to reduce these risks through credit analysis and attention to current developments and trends in both the economy and financial markets. Even though such securities do not pay current interest in cash, the Fund nonetheless is required to accrue interest income on these investments and to distribute the interest income on a current basis. Thus, the Fund could be required at times to sell other investments in order to satisfy its distribution requirements (including when it is not advantageous to do so).

The secondary market on which high yield securities are traded may be less liquid than the market for higher grade securities. Less liquidity in the secondary trading market could adversely affect the price at which the Fund could sell a high yield security, and could adversely affect the daily net asset value of the shares. Lower liquidity in secondary markets could adversely affect the value of high yield/high risk securities held by the Fund. While lower rated securities typically are less sensitive to interest rate changes than higher rated securities, the market prices of high yield/high risk securities structured as zero coupon bonds or PIKs may be affected to a greater extent by interest rate changes. For instance, adverse publicity and investor perceptions, whether or not based on fundamental analysis, may decrease the values and liquidity of high yield securities, especially in a thinly traded market. When secondary markets for high yield and distressed company securities are less liquid than the market for higher grade securities, it may be more difficult to value the securities because such valuation may require more research, and elements of judgment may play a greater role in the valuation because there is less reliable, objective data available. PIMCO seeks to minimize the risks of investing in all securities through in-depth credit analysis and attention to current developments in interest rates and market conditions.

The use of credit ratings as the sole method of evaluating high yield securities and debt securities of distressed companies can involve certain risks. For example, credit ratings evaluate the safety of principal and interest payments of a debt security, not the market value risk of the security. Also, credit rating agencies may fail to change credit ratings in a timely fashion to reflect events since the security was last rated. PIMCO does not rely solely on credit ratings when selecting debt securities for the Fund, and develops its own independent analysis of issuer credit quality. If a credit rating agency changes the rating of a debt security held by the Fund, the Fund may retain the security if PIMCO deems it in the best interest of shareholders.

Mortgage-related securities are interests in pools of residential or commercial mortgage loans, including mortgage loans made by savings and loan institutions, mortgage bankers, commercial banks and others. Such mortgage loans may include reperforming loans (“RPLs”), which are loans that have previously been delinquent but are current at the time securitized. Pools of mortgage loans are assembled as securities for sale to investors by various governmental, government-related and private organizations. The Fund may invest in a variety of mortgage-related and other asset-backed securities issued by government agencies or other governmental entities or by private originators or issuers.

The mortgage-related securities in which the Fund may invest include, without limitation, mortgage pass-through securities, collateralized mortgage obligations (“CMOs”), commercial or residential mortgage-backed securities, mortgage dollar rolls, CMO residuals, stripped mortgage-backed securities (“SMBSs”) and other securities that directly or indirectly represent a participation in, or are secured by and payable from, mortgage loans on real property. The Fund may also invest in other types of asset-backed securities, including collateralized debt obligations (“CDOs”), which include collateralized bond obligations (“CBOs”), collateralized loan obligations (“CLOs”) and other similarly structured securities. The mortgage-related securities in which the Fund may invest may pay variable or fixed rates of interest.

Through investments in mortgage-related securities, including those that are issued by private issuers, the Fund may have some exposure to subprime loans as well as to the mortgage and credit markets generally. Private issuers include commercial banks, savings associations, mortgage companies, investment banking firms, finance companies and special purpose finance entities (called special purpose vehicles or SPVs) and other entities that acquire and package mortgage loans for resale as mortgage-related securities.

Mortgage Pass-Through Securities. Mortgage pass-through securities are securities representing interests in “pools” of mortgage loans secured by residential or commercial real property. Interests in pools of mortgage-related securities differ from other forms of debt securities, which normally provide for periodic payment of interest in fixed or variable amounts with principal payments at maturity or specified call dates. Instead, these securities provide a monthly payment that consists of both interest and principal payments. In effect, these payments are a “pass-through” of the monthly payments made by the individual borrowers on their residential or commercial mortgage loans, net of any fees paid to the issuer or guarantor of such securities. Additional payments are caused by repayments of principal resulting from the sale of the underlying property, refinancing or foreclosure, net of fees or costs that may be incurred. Some mortgage-related securities (such as securities issued by the Government National Mortgage Association (“Ginnie Mae” or “GNMA”)) are described as “modified pass-through.” These securities entitle the holder to receive all interest and principal payments owed on the mortgage pool, net of certain fees, at the scheduled payment dates regardless of whether or not the mortgagor actually makes the payment.

The rate of prepayments on underlying mortgages will affect the price and volatility of a mortgage-related security, and may have the effect of shortening or extending the effective duration of the security relative to what was anticipated at the time of purchase. Early repayment of principal on some mortgage-related securities (arising from prepayments of principal due to the sale of the underlying property, refinancing, or foreclosure, net of fees and costs that may be incurred) may expose the Fund to a lower rate of return upon reinvestment of principal. Also, if a security subject

to prepayment has been purchased at a premium, the value of the premium would be lost in the event of prepayment. Like other fixed income securities, when interest rates rise, the value of a mortgage-related security generally will decline; however, when interest rates are declining, the value of mortgage-related securities with prepayment features may not increase as much as other fixed income securities. Adjustable rate mortgage-related and other asset-backed securities are also subject to some interest rate risk. For example, because interest rates on most adjustable rate mortgage- and other asset-backed securities only reset periodically (e.g., monthly or quarterly), changes in prevailing interest rates (and particularly sudden and significant changes) can be expected to cause some fluctuations in the market value of these securities, including declines in value as interest rates rise. In addition, to the extent that unanticipated rates of prepayment on underlying mortgages increase the effective duration of a mortgage-related security, the volatility of such security can be expected to increase.

The residential mortgage market in the United States recently has experienced difficulties that may adversely affect the performance and market value of certain of the Fund’s mortgage-related investments. Delinquencies and losses on residential mortgage loans (especially subprime and second-lien mortgage loans) generally have increased recently and may continue to increase, and a decline in or flattening of housing values (as has recently been experienced and may continue to be experienced in many housing markets) may exacerbate such delinquencies and losses. Borrowers with adjustable rate mortgage loans are more sensitive to changes in interest rates, which affect their monthly mortgage payments, and may be unable to secure replacement mortgages at comparably low interest rates. Also, a number of residential mortgage loan originators have experienced serious financial difficulties or bankruptcy. Owing largely to the foregoing, reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for certain mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen.

Agency Mortgage-Related Securities. Payment of principal and interest on some mortgage pass-through securities (but not the market value of the securities themselves) may be guaranteed by the full faith and credit of the U.S. Government (in the case of securities guaranteed by GNMA) or guaranteed by agencies or instrumentalities of the U.S. Government (in the case of securities guaranteed by the Federal National Mortgage Association (“Fannie Mae” or “FNMA”) or the Federal Home Loan Mortgage Corporation (“Freddie Mac” or “FHLMC”)). The principal governmental guarantor of mortgage-related securities is GNMA. GNMA is a wholly-owned U.S. Government corporation within the United States Department of Housing and Urban Development (the “Department of Housing and Urban Development” or “HUD”). GNMA 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 (such as savings and loan institutions, commercial banks and mortgage bankers) and backed by pools of mortgages insured by the Federal Housing Administration (the “FHA”), or guaranteed by the Department of Veterans Affairs (the “VA”).

Government-related guarantors (i.e., not backed by the full faith and credit of the U.S. Government) include FNMA and FHLMC. FNMA was, until recently, a government-sponsored corporation owned entirely by private stockholders, and subject to general regulation by HUD and the Office of Federal Housing Enterprise Oversight. As described below under “U.S. Government Securities,” FNMA is now under conservatorship by the Federal Housing Finance Agency (“FHFA”). FNMA

primarily purchases conventional (i.e., not insured or guaranteed by any government agency) residential mortgages from a list of approved seller/servicers, which includes state and federally chartered savings and loan associations, mutual savings banks, commercial banks, credit unions and mortgage bankers, although it may purchase other types of mortgages as well. Pass-through securities issued by FNMA are guaranteed as to timely payment of principal and interest by FNMA but are not backed by the full faith and credit of the U.S. Government. Instead, they are supported only by the discretionary authority of the U.S. Government to purchase the agency’s obligations.

FHLMC was created by Congress in 1970 for the purpose of increasing the availability of mortgage credit for residential housing. It was, until recently, a government-sponsored corporation formerly owned by the twelve Federal Home Loan Banks and then owned entirely by private stockholders. As described below under U.S. Government Securities, FHLMC is now under conservatorship by the FHFA. FHLMC issues Participation Certificates (“PCs”) which are pass-through securities, each representing an undivided interest in a pool of residential mortgages. FHLMC guarantees the timely payment of interest and ultimate collection of principal, but PCs are not backed by the full faith and credit of the U.S. Government. Instead, they are supported only by the discretionary authority of the U.S. Government to purchase the agency’s obligations.

FNMA and FHLMC also securitize RPLs. For example, in FNMA’s case, the RPLs are single-family, fixed rate reperforming loans that generally were previously placed in an MBS trust guaranteed by FNMA, purchased from the trust by FNMA and held as a distressed asset after four or more months of delinquency, and subsequently became current (i.e. performing) again. Such RPLs may have exited delinquency through efforts at reducing defaults (e.g., loan modification). In selecting RPLs for securitization, FNMA follows certain criteria related to length of time the loan has been performing, the type of loan (single-family, fixed rate), and the status of the loan as first lien, among other things. FNMA may include different loan structures and modification programs in the future.

On September 6, 2008, the FHFA placed FNMA and FHLMC into conservatorship. As the conservator, the FHFA succeeded to all rights, titles, powers and privileges of FNMA and FHLMC and of any stockholder, officer or director of FNMA and FHLMC with respect to FNMA and FHLMC and the assets of FNMA and FHLMC. FHFA selected a new chief executive officer and chairman of the board of directors for each of FNMA and FHLMC.

In connection with the conservatorship, the U.S. Department of the Treasury (the “U.S. Treasury”) entered into a Senior Preferred Stock Purchase Agreement with each of FNMA and FHLMC pursuant to which the U.S. Treasury will purchase up to an aggregate of $100 billion of each of FNMA and FHLMC to maintain a positive net worth in each enterprise. This agreement contains various covenants that severely limit each enterprise’s operations. In exchange for entering into these agreements, the U.S. Treasury received $1 billion of each enterprise’s senior preferred securities and warrants to purchase 79.9% of each enterprise’s common stock. On February 18, 2009, the U.S. Treasury announced that it was doubling the size of its commitment to each enterprise under the Senior Preferred Stock Program to $200 billion. The U.S. Treasury’s obligations under the Senior Preferred Stock Program are for an indefinite period of time for a maximum amount of $200 billion per enterprise. In 2009, the U.S. Treasury further amended the Senior Preferred Stock Purchase Agreement to allow the cap on the U.S. Treasury’s funding commitment to increase as necessary to accommodate any cumulative reduction in FNMA’s and FHLMC’s net worth through the end of 2012. In August 2012, the Senior Preferred Stock Purchase Agreement was further amended to, among other things, accelerate the wind down of the retained

portfolio, terminate the requirement that FNMA and FHLMC each pay a 10% dividend annually on all amounts received under the funding commitment, and require the submission of an annual risk management plan to the U.S. Treasury.

FNMA and FHLMC are continuing to operate as going concerns while in conservatorship and each remains liable for all of its obligations, including its guaranty obligations, associated with its mortgage-backed securities. The Senior Preferred Stock Purchase Agreement is intended to enhance each of FNMA’s and FHLMC’s ability to meet its obligations. The FHFA has indicated that the conservatorship of each enterprise will end when the director of FHFA determines that FHFA’s plan to restore the enterprise to a safe and solvent condition has been completed.

Under the Federal Housing Finance Regulatory Reform Act of 2008 (the “Reform Act”), which was included as part of the Housing and Economic Recovery Act of 2008, FHFA, as conservator or receiver, has the power to repudiate any contract entered into by FNMA or FHLMC prior to FHFA’s appointment as conservator or receiver, as applicable, if FHFA determines, in its sole discretion, that performance of the contract is burdensome and that repudiation of the contract promotes the orderly administration of FNMA’s or FHLMC’s affairs. The Reform Act requires FHFA to exercise its right to repudiate any contract within a reasonable period of time after its appointment as conservator or receiver.

FHFA, in its capacity as conservator, has indicated that it has no intention to repudiate the guaranty obligations of FNMA or FHLMC because FHFA views repudiation as incompatible with the goals of the conservatorship. However, in the event that FHFA, as conservator or if it is later appointed as receiver for FNMA or FHLMC, were to repudiate any such guaranty obligation, the conservatorship or receivership estate, as applicable, would be liable for actual direct compensatory damages in accordance with the provisions of the Reform Act. Any such liability could be satisfied only to the extent of FNMA’s or FHLMC’s assets available therefor.

In the event of repudiation, the payments of interest to holders of FNMA or FHLMC mortgage-backed securities would be reduced if payments on the mortgage loans represented in the mortgage loan groups related to such mortgage-backed securities are not made by the borrowers or advanced by the servicer. Any actual direct compensatory damages for repudiating these guaranty obligations may not be sufficient to offset any shortfalls experienced by such mortgage-backed security holders.

Further, in its capacity as conservator or receiver, FHFA has the right to transfer or sell any asset or liability of FNMA or FHLMC without any approval, assignment or consent. Although FHFA has stated that it has no present intention to do so, if FHFA, as conservator or receiver, were to transfer any such guaranty obligation to another party, holders of FNMA or FHLMC mortgage-backed securities would have to rely on that party for satisfaction of the guaranty obligation and would be exposed to the credit risk of that party.

In addition, certain rights provided to holders of mortgage-backed securities issued by FNMA and FHLMC under the operative documents related to such securities may not be enforced against FHFA, or enforcement of such rights may be delayed, during the conservatorship or any future receivership. The operative documents for FNMA and FHLMC mortgage-backed securities may provide (or with respect to securities issued prior to the date of the appointment of the conservator may have provided) that upon the occurrence of an event of default on the part of FNMA or FHLMC, in its capacity as guarantor, which includes the appointment of a conservator or receiver,

holders of such mortgage-backed securities have the right to replace FNMA or FHLMC as trustee if the requisite percentage of mortgage-backed securities holders consent. The Reform Act prevents mortgage-backed security holders from enforcing such rights if the event of default arises solely because a conservator or receiver has been appointed. The Reform Act also provides that no person may exercise any right or power to terminate, accelerate or declare an event of default under certain contracts to which FNMA or FHLMC is a party, or obtain possession of or exercise control over any property of FNMA or FHLMC, or affect any contractual rights of FNMA or FHLMC, without the approval of FHFA, as conservator or receiver, for a period of 45 or 90 days following the appointment of FHFA as conservator or receiver, respectively.

Privately Issued Mortgage-Related (Non-Agency) Securities. Commercial banks, savings and loan institutions, private mortgage insurance companies, mortgage bankers and other secondary market issuers also create pass-through pools of conventional residential mortgage loans. Such issuers may, in addition, be the originators and/or servicers of the underlying mortgage loans as well as the guarantors of the mortgage-related securities. Pools created by such non-governmental issuers generally offer a higher rate of interest than government and government-related pools because there are no direct or indirect government or agency guarantees of payments in the former pools. However, timely payment of interest and principal of these pools may be supported by various forms of insurance or guarantees, including individual loan, title, pool and hazard insurance and letters of credit, which may be issued by governmental entities, private insurers or the mortgage poolers. The insurance and guarantees are issued by governmental entities, private insurers and the mortgage poolers. Such insurance and guarantees, and the creditworthiness of the issuers thereof, will be considered in determining whether a mortgage-related security meets the Fund’s investment quality standards. There can be no assurance that the private insurers or guarantors can meet their obligations under the insurance policies or guarantee arrangements. The Fund may buy mortgage-related securities without insurance or guarantees if, through an examination of the loan experience and practices of the originator/servicers and poolers, the Investment Manager determines that the securities meet the Fund’s quality standards. Securities issued by certain private organizations may not be readily marketable.

Privately issued mortgage-related securities are not subject to the same underwriting requirements for the underlying mortgages that are applicable to those mortgage-related securities that have a government or government-sponsored entity guarantee. As a result, the mortgage loans underlying privately issued mortgage-related securities may, and frequently do, have less favorable collateral, credit risk or other underwriting characteristics than government or government-sponsored mortgage-related securities and have wider variances in a number of terms including interest rate, term, size, purpose and borrower characteristics. Mortgage pools underlying privately issued mortgage-related securities more frequently include second mortgages, high loan-to-value ratio mortgages and manufactured housing loans, in addition to commercial mortgages and other types of mortgages where a government or government sponsored entity guarantee is not available. The coupon rates and maturities of the underlying mortgage loans in a privately issued mortgage-related securities pool may vary to a greater extent than those included in a government guaranteed pool, and the pool may include subprime mortgage loans. Subprime loans are loans made to borrowers with weakened credit histories or with a lower capacity to make timely payments on their loans. For these reasons, the loans underlying these securities have had in many cases higher default rates than those loans that meet government underwriting requirements.

The risk of non-payment is greater for mortgage-related securities that are backed by loans that were originated under weak underwriting standards, including loans made to borrowers with limited means to make repayment. A level of risk exists for all loans, although, historically, the poorest performing loans have been those classified as subprime. Other types of privately issued mortgage-related securities, such as those classified as pay-option adjustable rate or Alt-A have also performed poorly. Even loans classified as prime have experienced higher levels of delinquencies and defaults. The substantial decline in real property values across the U.S. has exacerbated the level of losses that investors in privately issued mortgage-related securities have experienced. It is not certain when these trends may reverse. Market factors that may adversely affect mortgage loan repayment include adverse economic conditions, unemployment, a decline in the value of real property, or an increase in interest rates.

The Fund may purchase privately issued mortgage-related securities that are originated, packaged and serviced by third party entities. It is possible these third parties could have interests that are in conflict with the holders of mortgage-related securities, and such holders (such as the Fund) could have rights against the third parties or their affiliates. For example, if a loan originator, servicer or its affiliates engaged in negligence or willful misconduct in carrying out its duties, then a holder of the mortgage-related security could seek recourse against the originator/servicer or its affiliates, as applicable. Also, as a loan originator/servicer, the originator/servicer or its affiliates may make certain representations and warranties regarding the quality of the mortgages and properties underlying a mortgage-related security. If one or more of those representations or warranties is false, then the holders of the mortgage-related securities (such as the Fund) could trigger an obligation of the originator/servicer or its affiliates, as applicable, to repurchase the mortgages from the issuing trust. Notwithstanding the foregoing, many of the third parties that are legally bound by trust and other documents have failed to perform their respective duties, as stipulated in such trust and other documents, and investors have had limited success in enforcing terms. To the extent third party entities involved with privately issued mortgage-related securities are involved in litigation relating to the securities, actions may be taken that are adverse to the interests of holders of the mortgage-related securities, including the Fund. For example, third parties may seek to withhold proceeds due to holders of the mortgage-related securities, including the Fund, to cover legal or related costs. Any such action could result in losses to the Fund.

Privately issued mortgage-related securities are not traded on an exchange and there may be a limited market for the securities, especially when there is a perceived weakness in the mortgage and real estate market sectors. Without an active trading market, mortgage-related securities held in the Fund’s portfolio may be particularly difficult to value because of the complexities involved in assessing the value of the underlying mortgage loans.

The assets underlying mortgage-related securities may be represented by a portfolio of first lien residential or commercial mortgages (including both whole mortgage loans and mortgage participation interests that may be senior or junior in terms of priority of repayment) or portfolios of mortgage pass-through securities issued or guaranteed by GNMA, FNMA or FHLMC. Mortgage loans underlying a mortgage-related security may in turn be insured or guaranteed by the FHA or the VA. In the case of privately issued mortgage-related securities whose underlying assets are neither U.S. Government securities nor U.S. Government-insured mortgages, to the extent that real properties securing such assets may be located in the same geographical region, the security may be subject to a greater risk of default than other comparable securities in the event of adverse economic, political or business developments that may affect such region and, ultimately, the ability of residential homeowners to make payments of principal and interest on the underlying mortgages.

The Investment Manager seeks to manage the portion of the Fund’s assets committed to privately issued mortgage-related securities in a manner consistent with the Fund’s investment objective, policies and overall portfolio risk profile. In determining whether and how much to invest in privately issued mortgage-related securities, and how to allocate those assets, the Investment Manager will consider a number of factors. These include, but are not limited to: (1) the nature of the borrowers (e.g., residential vs. commercial); (2) the collateral loan type (e.g., for residential: First Lien - Jumbo/Prime, First Lien - Alt-A, First Lien - Subprime, First Lien - Pay-Option or Second Lien; for commercial: Conduit, Large Loan or Single Asset / Single Borrower); and (3) in the case of residential loans, whether they are fixed rate or adjustable mortgages. Each of these criteria can cause privately issued mortgage-related securities to have differing primary economic characteristics and distinguishable risk factors and performance characteristics.

Collateralized Mortgage Obligations (“CMOs”). A CMO is a debt obligation of a legal entity that is collateralized by mortgages and divided into classes. A CMO is a hybrid between a mortgage-backed bond and a mortgage pass-through security. Similar to a bond, interest and prepaid principal is paid, in most cases, semi-annually or on a monthly basis. CMOs may be collateralized by whole mortgage loans or private mortgage bonds, but are more typically collateralized by portfolios of mortgage pass-through securities issued or guaranteed by GNMA, FNMA or FHLMC, and their income streams.

CMOs are structured into multiple classes, often referred to as “tranches,” with each class bearing a different stated maturity and entitled to a different schedule for payments of principal and interest, including prepayments. Actual maturity and average life will depend upon the prepayment experience of the collateral. CMOs provide for a modified form of call protection through a de facto breakdown of the underlying pool of mortgages according to how quickly the loans are repaid. In the case of certain CMOs (known as “sequential pay” CMOs), payment of principal received from the pool of underlying mortgages, including prepayments, are applied to the classes of CMOs in the order of their respective final distribution dates. Thus, no payment of principal will be made to any class of sequential pay CMOs until all other classes having an earlier final distribution date have been paid in full. An investor is partially guarded against a sooner than desired return of principal because of the sequential payments.

In a typical CMO transaction, a corporation (“issuer”) issues multiple series (e.g., A, B, C, Z) of CMO bonds (“Bonds”). Proceeds of the Bond offering are used to purchase mortgages or mortgage pass-through certificates (“Collateral”). The Collateral is pledged to a third party trustee as security for the Bonds. Principal and interest payments from the Collateral are used to pay principal on the Bonds in the order A, B, C, Z. The Series A, B, and C Bonds all bear current interest. Interest on the Series Z Bond is accrued and added to principal and a like amount is paid as principal on the Series A, B, or C Bond currently being paid off. When the Series A, B, and C Bonds are paid in full, interest and principal on the Series Z Bond begin to be paid currently.

With some CMOs, the issuer serves as a conduit to allow loan originators (primarily builders or savings and loan associations) to borrow against their loan portfolios. CMOs may be less liquid and may exhibit greater price volatility than other types of mortgage- or ABS.

As CMOs have evolved, some classes of CMO bonds have become more common. For example, the Fund may invest in parallel-pay and planned amortization class (“PAC”) CMOs and multi-class pass-through certificates. Parallel-pay CMOs and multi-class pass-through certificates are structured to provide payments of principal on each payment date to more than one class. These simultaneous

payments are taken into account in calculating the stated maturity date or final distribution date of each class, which, as with other CMO and multi-class pass-through structures, must be retired by its stated maturity date or final distribution date but may be retired earlier. PACs generally require payments of a specified amount of principal on each payment date. PACs are parallel-pay CMOs with the required principal amount on such securities having the highest priority after interest has been paid to all classes. Any CMO or multi-class pass-through structure that includes PAC securities must also have support tranches—known as support bonds, companion bonds or non-PAC bonds—which lend or absorb principal cash flows to allow the PAC securities to maintain their stated maturities and final distribution dates within a range of actual prepayment experience. These support tranches are subject to a higher level of maturity risk compared to other mortgage-related securities, and usually provide a higher yield to compensate investors. If principal cash flows are received in amounts outside a pre-determined range such that the support bonds cannot lend or absorb sufficient cash flows to the PAC securities as intended, the PAC securities are subject to heightened maturity risk. Consistent with the Fund’s investment objective and policies, PIMCO may invest in various tranches of CMO bonds, including support bonds.

CMOs that are issued or guaranteed by the U.S. Government or by any of its agencies or instrumentalities will be considered U.S. Government securities by the Fund, while other CMOs, even if collateralized by U.S. Government securities, will have the same status as other privately issued securities for purposes of applying the Fund’s diversification tests.

FHLMC Collateralized Mortgage Obligations. FHLMC CMOs are debt obligations of FHLMC issued in multiple classes having different maturity dates which are secured by the pledge of a pool of conventional mortgage loans purchased by FHLMC. Payments of principal and interest on the CMOs are made semi-annually, as opposed to monthly. The amount of principal payable on each semi-annual payment date is determined in accordance with FHLMC’s mandatory sinking fund schedule, which in turn, is equal to approximately 100% of FHA prepayment experience applied to the mortgage collateral pool. All sinking fund payments in the CMOs are allocated to the retirement of the individual classes of bonds in the order of their stated maturities. Payment of principal on the mortgage loans in the collateral pool in excess of the amount of FHLMC’s minimum sinking fund obligation for any payment date are paid to the holders of the CMOs as additional sinking fund payments. Because of the “pass-through” nature of all principal payments received on the collateral pool in excess of FHLMC’s minimum sinking fund requirement, the rate at which principal of the CMOs is actually repaid is likely to be such that each class of bonds will be retired in advance of its scheduled maturity date.

If collection of principal (including prepayments) on the mortgage loans during any semi-annual payment period is not sufficient to meet FHLMC’s minimum sinking fund obligation on the next sinking fund payment date, FHLMC agrees to make up the deficiency from its general funds.

Criteria for the mortgage loans in the pool backing the FHLMC CMOs are identical to those of FHLMC PCs. FHLMC has the right to substitute collateral in the event of delinquencies and/or defaults.

Commercial Mortgage-Backed Securities. Commercial mortgage-backed securities include securities that reflect an interest in, and are secured by, mortgage loans on commercial real property. Many of the risks of investing in commercial mortgage-backed securities reflect the risks of investing in the real estate securing the underlying mortgage loans. These risks reflect the effects of local and other economic conditions on real estate markets, the ability of tenants to make loan payments, and the ability of a property to attract and retain tenants. Commercial mortgage-backed securities may be less liquid and exhibit greater price volatility than other types of mortgage- or ABS.

The cash flow generated by the mortgage assets underlying a series of CMOs is applied first to make required payments of principal and interest on the CMOs and second to pay the related administrative expenses and any management fee of the issuer. The residual in a CMO structure generally represents the interest in any excess cash flow remaining after making the foregoing payments. Each payment of such excess cash flow to a holder of the related CMO residual represents income and/or a return of capital. The amount of residual cash flow resulting from a CMO will depend on, among other things, the characteristics of the mortgage assets, the coupon rate of each class of CMO, prevailing interest rates, the amount of administrative expenses and the pre-payment experience on the mortgage assets. In particular, the yield to maturity on CMO residuals is extremely sensitive to pre-payments on the related underlying mortgage assets, in the same manner as an interest-only (“IO”) class of SMBSs. See “Stripped Mortgage-Backed Securities” below. In addition, if a series of a CMO includes a class that bears interest at an adjustable rate, the yield to maturity on the related CMO residual will also be extremely sensitive to changes in the level of the index upon which interest rate adjustments are based. As described below with respect to SMBSs, in certain circumstances the Fund may fail to recoup fully its initial investment in a CMO residual.

CMO residuals are generally purchased and sold by institutional investors through several investment banking firms acting as brokers or dealers. Transactions in CMO residuals are generally completed only after careful review of the characteristics of the securities in question. In addition, CMO residuals may, or pursuant to an exemption therefrom, may not, have been registered under the Securities Act of 1933, as amended (the “1933 Act”). CMO residuals, whether or not registered under the 1933 Act, may be subject to certain restrictions on transferability and may be deemed “illiquid.”

Adjustable Rate Mortgage Backed Securities. Adjustable rate mortgage-backed securities (“ARMBSs”) have interest rates that reset at periodic intervals. Acquiring ARMBSs permits the Fund to participate in increases in prevailing current interest rates through periodic adjustments in the coupons of mortgages underlying the pool on which ARMBSs are based. Such ARMBSs generally have higher current yield and lower price fluctuations than is the case with more traditional fixed income debt securities of comparable rating and maturity. In addition, when prepayments of principal are made on the underlying mortgages during periods of rising interest rates, the Fund can reinvest the proceeds of such prepayments at rates higher than those at which they were previously invested. Mortgages underlying most ARMBSs, however, have limits on the allowable annual or lifetime increases that can be made in the interest rate that the mortgagor pays. Therefore, if current interest rates rise above such limits over the period of the limitation, the Fund, when holding an ARMBS, does not benefit from further increases in interest rates. Moreover, when interest rates are in excess of coupon rates (i.e., the rates being paid by mortgagors) of the mortgages, ARMBSs behave more like fixed income securities and less like adjustable rate securities and are subject to the risks associated with fixed income securities. In addition, during periods of rising interest rates, increases in the coupon rate of adjustable rate mortgages generally lag current market interest rates slightly, thereby creating the potential for capital depreciation on such securities.

Stripped Mortgage-Backed Securities. SMBS are derivative multi-class mortgage securities. SMBSs may be issued by agencies or instrumentalities of the U.S. Government, or by private originators of, or investors in, mortgage loans, including savings and loan associations, mortgage banks, commercial banks, investment banks and special purpose entities of the foregoing.

SMBSs are usually structured with two classes that receive different proportions of the interest and principal distributions on a pool of mortgage assets. A common type of SMBS will have one class receiving some of the interest and most of the principal from the mortgage assets, while the other class will receive most of the interest and the remainder of the principal. In the most extreme case, one class will receive all of the interest (the “IO” class), while the other class will receive all of the principal (the “PO” class). The yield to maturity on an IO class is extremely sensitive to the rate of principal payments (including prepayments) on the related underlying mortgage assets, and a rapid rate of principal payments may have a material adverse effect on the Fund’s yield to maturity from these securities. If the underlying mortgage assets experience greater than anticipated prepayments of principal, the Fund may fail to recoup some or all of its initial investment in these securities even if the security is in one of the highest rating categories. SMBSs may be deemed “illiquid.”

Other Mortgage-Related Securities. Other mortgage-related securities include securities other than those described above that directly or indirectly represent a participation in, or are secured by and payable from, mortgage loans on real property, including mortgage dollar rolls, CMO residuals or SMBSs. Other mortgage-related securities may be equity or debt securities issued by agencies or instrumentalities of the U.S. Government or by private originators of, or investors in, mortgage loans, including savings and loan associations, homebuilders, mortgage banks, commercial banks, investment banks, partnerships, trusts and special purpose entities of the foregoing.

Mortgage-related securities include, among other things, securities that reflect an interest in reverse mortgages. In a reverse mortgage, a lender makes a loan to a homeowner based on the homeowner’s equity in his or her home. While a homeowner must be age 62 or older to qualify for a reverse mortgage, reverse mortgages may have no income restrictions. Repayment of the interest or principal for the loan is generally not required until the homeowner dies, sells the home, or ceases to use the home as his or her primary residence.

There are three general types of reverse mortgages: (1) single-purpose reverse mortgages, which are offered by certain state and local government agencies and nonprofit organizations; (2) federally-insured reverse mortgages, which are backed by the U. S. Department of Housing and Urban Development; and (3) proprietary reverse mortgages, which are privately offered loans. A mortgage-related security may be backed by a single type of reverse mortgage. Reverse mortgage-related securities include agency and privately issued mortgage-related securities. The principal government guarantor of reverse mortgage-related securities is GNMA.

Reverse mortgage-related securities may be subject to risks different than other types of mortgage-related securities due to the unique nature of the underlying loans. The date of repayment for such loans is uncertain and may occur sooner or later than anticipated. The timing of payments for the corresponding mortgage-related security may be uncertain. Because reverse mortgages are offered only to persons 62 and older and there may be no income restrictions, the loans may react

differently than traditional home loans to market events. Additionally, there can be no assurance that service providers to reverse mortgage trusts (RMTs) will diligently and appropriately execute their duties with respect to servicing such trusts. As a result, investors (which may include the Fund) in notes issued by RMTs may be deprived of payments to which they are entitled. This could result in losses to the Fund. Investors, including the Fund, may determine to pursue negotiations or legal claims or otherwise seek compensation from RMT service providers in certain instances. This may involve the Fund incurring costs and expenses associated with such actions.

Asset-Backed Securities. The Fund may invest in, or have exposure to, ABS, which are securities that represent a participation in, or are secured by and payable from, a stream of payments generated by particular assets, most often a pool or pools of similar assets (e.g., trade receivables). The credit quality of these securities depends primarily upon the quality of the underlying assets and the level of credit support and/or enhancement provided.

The underlying assets (e.g., loans) are subject to prepayments that shorten the securities’ weighted average maturity and may lower their return. If the credit support or enhancement is exhausted, losses or delays in payment may result if the required payments of principal and interest are not made. The value of these securities also may change because of changes in the market’s perception of the creditworthiness of the servicing agent for the pool, the originator of the pool, or the financial institution or trust providing the credit support or enhancement. Typically, there is no perfected security interest in the collateral that relates to the financial assets that support ABS. Asset-backed securities have many of the same characteristics and risks as the mortgage backed securities described above.

The Fund may purchase or have exposure to commercial paper, including asset-backed commercial paper (“ABCP”), that is issued by structured investment vehicles or other conduits. These conduits may be sponsored by mortgage companies, investment banking firms, finance companies, hedge funds, private equity firms and special purpose finance entities. ABCP typically refers to a short-term debt security, the payment of which is supported by cash flows from underlying assets, or one or more liquidity or credit support providers, or both. Assets backing ABCP include credit card, car loan and other consumer receivables and home or commercial mortgages, including subprime mortgages. The repayment of ABCP issued by a conduit depends primarily on the cash collections received from the conduit’s underlying asset portfolio and the conduit’s ability to issue new ABCP. Therefore, there could be losses to the Fund if investing in ABCP in the event of credit or market value deterioration in the conduit’s underlying portfolio, mismatches in the timing of the cash flows of the underlying asset interests and the repayment obligations of maturing ABCP, or the conduit’s inability to issue new ABCP. To protect investors from these risks, ABCP programs may be structured with various protections, such as credit enhancement, liquidity support, and commercial paper stop-issuance and wind-down triggers. However, there can be no guarantee that these protections will be sufficient to prevent losses to investors in ABCP. Some ABCP programs provide for an extension of the maturity date of the ABCP if, on the related maturity date, the conduit is unable to access sufficient liquidity through the issue of additional ABCP. This may delay the sale of the underlying collateral and the Fund may incur a loss if the value of the collateral deteriorates during the extension period. Alternatively, if collateral for ABCP deteriorates in value, the collateral may be required to be sold at inopportune times or at prices insufficient to repay the principal and interest on the ABCP. ABCP programs may provide for the issuance of subordinated notes as an additional form of credit enhancement. The subordinated notes are typically of a lower credit quality and have a higher risk of default. To the extent the Fund purchases these subordinated notes, it will have a higher likelihood of loss than investors in the senior notes.

Some ABS, particularly home equity loan transactions, are subject to interest-rate risk and prepayment risk. A change in interest rates can affect the pace of payments on the underlying loans, which in turn, affects total return on the securities. Asset-backed securities also carry credit or default risk. If many borrowers on the underlying loans default, losses could exceed the credit enhancement level and result in losses to investors in an Asset-backed securities transaction. Finally, ABS have structure risk due to a unique characteristic known as early amortization, or early payout, risk. Built into the structure of most asset-backed securities (“ABS”) are triggers for early payout, designed to protect investors from losses. These triggers are unique to each transaction and can include: a big rise in defaults on the underlying loans, a sharp drop in the credit enhancement level, or even the bankruptcy of the originator. Once early amortization begins, all incoming loan payments (after expenses are paid) are used to pay investors as quickly as possible based upon a predetermined priority of payment.

Collateralized Bond Obligations, Collateralized Loan Obligations and Other Collateralized Debt Obligations. The Fund may invest in each of CBOs, CLOs, other CDOs and other similarly structured securities. CBOs, CLOs and other CDOs are types of asset-backed securities. A CBO is a trust that is often backed by a diversified pool of high risk, below investment grade fixed income securities. The collateral can be from many different types of fixed-income securities such as high-yield debt, residential privately issued mortgage-related securities, commercial privately issued mortgage-related securities, trust preferred securities and emerging market debt. A CLO is a trust typically collateralized by a pool of loans, which may include, among others, domestic and foreign senior secured loans, senior unsecured loans and subordinate corporate loans, including loans that may be rated below investment grade or equivalent unrated loans. Other CDOs are trusts backed by other types of assets representing obligations of various parties. CBOs, CLOs and other CDOs may charge management fees and administrative expenses.

For CBOs, CLOs and other CDOs, the cash flows from the trust are split into two or more portions, called tranches, varying in risk and yield. The riskiest portion is the “equity” tranche which bears the bulk of defaults from the bonds or loans in the trust and serves to protect the other, more senior tranches from default in all but the most severe circumstances. Since it is partially protected from defaults, a senior tranche from a CBO trust, CLO trust or trust of another CDO typically have higher ratings and lower yields than their underlying securities, and can be rated investment grade. Despite the protection from the equity tranche, CBO, CLO or other CDO tranches can experience substantial losses due to actual defaults, downgrades of the underlying collateral by rating agencies, forced liquidation of the collateral pool due to a failure of coverage tests, increased sensitivity to defaults due to collateral default and disappearance of protecting tranches, market anticipation of defaults, as well as aversion to CBO, CLO or other CDO securities as a class. Interest on certain tranches of a CDO may be paid in kind or deferred and capitalized (paid in the form of obligations of the same type rather than cash), which involves continued exposure to default risk with respect to such payments.

The risks of an investment in a CBO, CLO or other CDO depend largely on the type of the collateral securities and the class of the instrument in which the Fund invests. Normally, CBOs, CLOs and other CDOs are privately offered and sold, and thus, are not registered under the securities laws. As a result, investments in CBOs, CLOs and other CDOs may be characterized by the Fund as illiquid securities. However, an active dealer market may exist for CBOs, CLOs and other CDOs allowing them to qualify for Rule 144A transactions. In addition to the normal risks associated with fixed income securities discussed elsewhere in this Statement of Additional Information and the Prospectus (e.g., prepayment risk, credit risk, liquidity risk, market risk,

structural risk, legal risk and interest rate risk (which may be exacerbated if the interest rate payable on a structured financing changes based on multiples of changes in interest rates or inversely to changes in interest rates) and default risk), CBOs, CLOs and other CDOs carry additional risks that include, but are not limited to: (i) the possibility that distributions from collateral securities will not be adequate to make interest or other payments; (ii) the risk that the quality of the collateral may decline in value or default; (iii) the risk that the Fund may invest in tranches CBOs, CLOs or other CDOs that are subordinate to other classes; and (iv) the complex structure of the security may not be fully understood at the time of investment and may produce disputes with the issuer or unexpected investment results; (v) the investment return achieved by the Fund could be significantly different than those predicted by financial models; (vi) the lack of a readily available secondary market for CDOs; (vii) risk of forced “fire sale” liquidation due to technical defaults such as coverage test failures; and (viii) the CDO’s manager may perform poorly.

Other Asset-Backed Securities. Similarly, PIMCO expects that other asset-backed securities (unrelated to mortgage loans) will be offered to investors in the future and may be purchased by the Fund.

Several types of asset-backed securities have already been offered to investors, including Enhanced Equipment Trust Certificates (“EETCs”) and Certificates for Automobile Receivables^SM (“CARS^SM”).

EETCs are typically issued by specially-created trusts established by airlines, railroads, or other transportation corporations. The proceeds of EETCs are used to purchase equipment, such as airplanes, railroad cars, or other equipment, which in turn serve as collateral for the related issue of the EETCs. The equipment generally is leased by the airline, railroad or other corporation, which makes rental payments to provide the projected cash flow for payments to EETC holders. Holders of EETCs must look to the collateral securing the certificates, typically together with a guarantee provided by the lessee corporation or its parent company for the payment of lease obligations, in the case of default in the payment of principal and interest on the EETCs. However, because principal and interest payments on EETCs are funded in the ordinary course by the lessee corporation, the Fund treats EETCs as corporate bonds/obligations for purposes of compliance testing and related classifications.

CARS^SM represent undivided fractional interests in a trust whose assets consist of a pool of motor vehicle retail installment sales contracts and security interests in the vehicles securing the contracts. Payments of principal and interest on CARS^SM are passed through monthly to certificate holders, and are guaranteed up to certain amounts and for a certain time period by a letter of credit issued by a financial institution unaffiliated with the trustee or originator of the trust. An investor’s return on CARS^SM may be affected by early prepayment of principal on the underlying vehicle sales contracts. If the letter of credit is exhausted, the trust may be prevented from realizing the full amount due on a sales contract because of state law requirements and restrictions relating to foreclosure sales of vehicles and the obtaining of deficiency judgments following such sales or because of depreciation, damage or loss of a vehicle, the application of federal and state bankruptcy and insolvency laws, or other factors. As a result, certificate holders may experience delays in payments or losses if the letter of credit is exhausted.

Consistent with the Fund’s investment objective and policies, PIMCO also may invest in other types of asset-backed and related securities (such as credit card receivables or student loans). Other asset-backed securities may be collateralized by the fees earned by service providers. The value of

asset-backed securities may be substantially dependent on the servicing of the underlying asset pools and are therefore subject to risks associated with the negligence by, or defalcation of, their servicers. In certain circumstances, the mishandling of related documentation may also affect the rights of the security holders in and to the underlying collateral. The insolvency of entities that generate receivables or that utilize the assets may result in added costs and delays in addition to losses associated with a decline in the value of the underlying assets.

Investors should note that Congress from time to time may consider actions that would limit or remove the explicit or implicit guarantee of the payment of principal and/or interest on many types of asset-backed securities. Any such action would likely adversely impact the value of such securities.

The Fund may generally gain exposure to the real estate sector by investing in real-estate linked derivatives, real estate investment trusts (“REITs”) and common, preferred and convertible securities of issuers in real estate-related industries. The Fund may also invest in loans or other investments secured by real estate (other than mortgage-backed securities) and may, as a result of default, foreclosure or otherwise, take possession of and hold real estate as a direct owner (see “Loans and Other Indebtedness; Loan Participations and Assignments” below). Each of these types of investments are subject, directly or indirectly, to risks associated with ownership of real estate, including changes in the general economic climate or local conditions (such as an oversupply of space or a reduction in demand for space), loss to casualty or condemnation, increases in property taxes and operating expenses, zoning law amendments, changes in interest rates, overbuilding and increased competition, including competition based on rental rates, variations in market value, changes in the financial condition of tenants, changes in operating costs, attractiveness and location of the properties, adverse changes in the real estate markets generally or in specific sectors of the real estate industry and possible environmental liabilities. Real estate-related investments may entail leverage and may be highly volatile.

REITs are pooled investment vehicles that own, and typically operate, income-producing real estate. If a REIT meets certain requirements, including distributing to shareholders substantially all of its taxable income (other than net capital gains), then it is not generally taxed on the income distributed to shareholders. REITs are subject to management fees and other expenses, and so the Fund would bear its proportionate share of the costs of the REITs’ operations if it invests in REITs.

There are three general categories of REITs: Equity REITs, Mortgage REITs and Hybrid REITs. Equity REITs invest primarily in direct fee ownership or leasehold ownership of real property; they derive most of their income from rents. Mortgage REITs invest mostly in mortgages on real estate, which may secure construction, development or long-term loans, and the main source of their income is mortgage interest payments. Hybrid REITs hold both ownership and mortgage interests in real estate.

Along with the risks common to different types of real estate related securities, REITs, no matter the type, involve additional risk factors. These include poor performance by the REIT’s manager, adverse changes to the tax laws, and failure by the REIT to qualify for tax-free distribution of income or exemption under the 1940 Act or tax-free pass-through of income under the Internal Revenue Code of 1986, as amended (the “Code”). In addition, some REITS have limited diversification because they invest in a limited number of properties, a narrow geographic area, or a

single type of property. Also, the organizational documents of a REIT may contain provisions that make changes in control of the REIT difficult and time-consuming. Finally, private REITs are not traded on a national securities exchange. As such, these products are generally illiquid. This reduces the ability of the Fund to redeem its investment early. Private REITS are also generally harder to value and may bear higher fees than public REITs.

Some of the REITs in which the Fund may invest may be permitted to hold senior or residual interests in real estate mortgage investment conduits (“REMICs”) or debt or equity interests in taxable mortgage pools (“TMPs”). The Fund may also hold interests in “Re-REMICs”, which are interests in securitizations formed by the contribution of asset backed or other similar securities into a trust which then issues securities in various tranches. The Fund may participate in the creation of a Re-REMIC by contributing assets to the trust and receiving junior and/or senior securities in return. An interest in a Re-REMIC security may be riskier than the securities originally held by and contributed to the trust, and the holders of the Re-REMIC securities will bear the costs associated with the securitization.

The Fund may invest up to 25% of its total assets (measured at the time of investment) in non-U.S. dollar denominated securities (of both developed and “emerging market” countries), including obligations of non-U.S. governments and their respective sub-divisions, agencies and government-sponsored enterprises. The Fund may invest in sovereign and other debt securities issued by foreign governments and their respective sub-divisions, agencies or instrumentalities, government sponsored enterprises and supranational government entities. The Fund may also invest directly in foreign currencies, including local emerging market currencies. The foreign securities in which the Fund may invest include without limit Eurodollar obligations and “Yankee Dollar” obligations. Eurodollar obligations are U.S. dollar-denominated certificates of deposit and time deposits issued outside the U.S. capital markets by foreign branches of U.S. banks and by foreign banks. Yankee Dollar obligations are U.S. dollar-denominated obligations issued in the U.S. capital markets by foreign banks. Eurodollar and Yankee Dollar obligations are generally subject to the same risks that apply to domestic debt issues, notably credit risk, interest rate risk, market risk and liquidity risk. Additionally, Eurodollar (and to a limited extent, Yankee Dollar) obligations are subject to certain sovereign risks. One such risk is the possibility that a sovereign country might prevent capital, in the form of U.S. dollars, from flowing across its borders. Other risks include adverse political and economic developments; the extent and quality of government regulation of financial markets and institutions; the imposition of foreign withholding or other taxes; and the expropriation or nationalization of foreign issuers.

The Fund may also invest in American Depositary Receipts (“ADRs”), European Depositary Receipts (“EDRs”) or Global Depositary Receipts (“GDRs”). ADRs are U.S. dollar-denominated receipts issued generally by domestic banks and represent the deposit with the bank of a security of a non-U.S. issuer. EDRs are foreign currency-denominated receipts similar to ADRs and are issued and traded in Europe, and are publicly traded on exchanges or over-the-counter (“OTC”) in the United States. GDRs may be offered privately in the United States and also trade in public or private markets in other countries. ADRs, EDRs and GDRs may be issued as sponsored or unsponsored programs. In sponsored programs, an issuer has made arrangements to have its securities trade in the form of ADRs, EDRs or GDRs. In unsponsored programs, the issuer may not be directly involved in the creation of the program. Although regulatory requirements with respect to sponsored and unsponsored programs are generally similar, in some cases it may be easier to obtain financial information from an issuer that has participated in the creation of a sponsored program.

Investing in non-U.S. securities involves special risks and considerations not typically associated with investing in U.S. securities. These include: differences in accounting, auditing and financial reporting standards, generally higher commission rates on non-U.S. portfolio transactions, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations (which may include suspension of the ability to transfer currency from a country), market disruption, the possibility of security suspensions, political instability which can affect U.S. investments in non-U.S. countries and potential restrictions on the flow of international capital. In addition, foreign securities and the Fund’s income in respect of those securities may be subject to foreign taxes, including taxes withheld from payments on those securities, which would reduce the Fund’s return on such securities. Non-U.S. securities often trade with less frequency and volume than domestic securities and therefore may exhibit greater price volatility. Changes in foreign exchange rates will affect the value of those securities that are denominated or quoted in currencies other than the U.S. dollar. The currencies of non-U.S. countries may experience significant declines against the U.S. dollar, and devaluation may occur subsequent to investments in these currencies by the Fund.

Investment in sovereign debt can involve a high degree of risk. The governmental entity that controls the repayment of sovereign debt may not be able or willing to repay the principal and/or interest when due in accordance with the terms of the debt. A governmental entity’s willingness or ability to repay principal and interest due in a timely manner may be affected by, among other factors, its cash flow situation, the extent of its foreign reserves, the availability of sufficient foreign exchange on the date a payment is due, the relative size of the debt service burden to the economy as a whole, the governmental entity’s policy toward the International Monetary Fund, and the political constraints to which a governmental entity may be subject. Governmental entities may also depend on expected disbursements from foreign governments, multilateral agencies and others to reduce principal and interest arrearages on their debt. The commitment on the part of these governments, agencies and others to make such disbursements may be conditioned on a governmental entity’s implementation of economic reforms and/or economic performance and the timely service of such debtor’s obligations. Failure to implement such reforms, achieve such levels of economic performance or repay principal or interest when due may result in the cancellation of such third parties’ commitments to lend funds to the governmental entity, which may further impair such debtor’s ability or willingness to service its debts in a timely manner. Consequently, governmental entities may default on their sovereign debt. Holders of sovereign debt (including the Fund) may be requested to participate in the rescheduling of such debt and to extend further loans to governmental entities. There is no bankruptcy proceeding by which sovereign debt on which governmental entities have defaulted may be collected in whole or in part.

The investments in foreign currency denominated debt obligations and hedging activities by the Fund will likely produce a difference between the Fund’s book income and its taxable income. This difference may cause a portion of the Fund’s income distributions to constitute returns of capital for tax purposes or require the Fund to make distributions exceeding book income to qualify as a regulated investment company for U.S. federal tax purposes. The Fund’s investments in non-U.S. securities may increase or accelerate the amount of ordinary income recognized by shareholders. See “Taxation.”

Euro- and EU-related risks. The global economic crisis brought several small economies in Europe to the brink of bankruptcy and many other economies into recession and weakened the banking and financial sectors of many European countries. For example, the governments of Greece, Spain, Portugal, and the Republic of Ireland have all experienced large public budget deficits, the effects of which are still yet unknown and may slow the overall recovery of the European economies from the global economic crisis. In addition, due to large public deficits, some European countries may be dependent on assistance from other European governments and institutions or other central banks or supranational agencies such as the International Monetary Fund. Assistance may be dependent on a country’s implementation of reforms or reaching a certain level of performance. Failure to reach those objectives or an insufficient level of assistance could result in a deep economic downturn which could significantly affect the value of the Fund’s European investments.

The Economic and Monetary Union of the European Union (“EMU”) is comprised of the European Union (“EU”) members that have adopted the euro currency. By adopting the euro as its currency, a member state relinquishes control of its own monetary policies. As a result, European countries are significantly affected by fiscal and monetary policies implemented by the EMU and European Central Bank. The euro currency may not fully reflect the strengths and weaknesses of the various economies that comprise the EMU and Europe generally. It is possible that one or more EMU member countries could abandon the euro and return to a national currency and/or that the euro will cease to exist as a single currency in its current form. The effects of such an abandonment or a country’s forced expulsion from the euro on that country, the rest of the EMU, and global markets are impossible to predict, but are likely to be negative. The exit of any country out of the euro may have an extremely destabilizing effect on other Eurozone countries and their economies and a negative effect on the global economy as a whole. Such an exit by one country may also increase the possibility that additional countries may exit the euro should they face similar financial difficulties. In addition, in the event of one or more countries’ exit from the euro, it may be difficult to value investments denominated in euros or in a replacement currency.

The Fund may face potential risks associated with the referendum on the United Kingdom’s continued membership in the EU, which resulted in a vote for the United Kingdom to leave the EU. The vote to leave the EU may result in substantial volatility in foreign exchange markets and may lead to a sustained weakness in the British pound’s exchange rate against the United States dollar, the euro and other currencies, which may impact Fund returns. The vote to leave the EU may result in a sustained period of market uncertainty, as the United Kingdom seeks to negotiate the terms of its exit. It may also destabilize some or all of the other EU member countries and/or the Eurozone. These developments could result in losses to the Fund, as there may be negative effects on the value of Fund’s investments and/or on Fund’s ability to enter into certain transactions or value certain investments, and these developments may make it more difficult for the Fund to exit certain investments at an advantageous time or price. Such events could result from, among other things, increased uncertainty and volatility in the United Kingdom, the EU and other financial markets; fluctuations in asset values; fluctuations in exchange rates; decreased liquidity of investments located, traded or listed within the United Kingdom, the EU or elsewhere; changes in the willingness or ability of financial and other counterparties to enter into transactions or the price and terms on which other counterparties are willing to transact; and/or changes in legal and regulatory regimes to which Fund investments are or become subject. Any of these events, as well as an exit or expulsion of an EU member state other than the United Kingdom from the EU, could negatively impact Fund returns.

Investments in Russia. The Fund may invest in securities and instruments that are economically tied to Russia. In addition to the risks listed above under “Foreign (Non-U.S.) Securities,” investing in Russia presents additional risks. In particular, investments in Russia are subject to various risks such as political, economic, legal, market and currency risks. The risks include uncertain political and economic policies, short term market volatility, poor accounting standards, corruption and crime, an inadequate regulatory system, and unpredictable taxation. Investments in Russia are particularly subject to the risk that economic sanctions may be imposed by the United States and/or other countries. Such sanctions — which may impact companies in many sectors, including energy, financial services and defense, among others — may negatively impact the Fund’s performance and/or ability to achieve its investment objective. The Russian securities market is characterized by limited volume of trading, resulting in difficulty in obtaining accurate prices. The Russian securities market, as compared to U.S. markets, has significant price volatility, less liquidity, a smaller market capitalization and a smaller number of traded securities. There may be little publicly available information about issuers. Settlement, clearing and registration of securities transactions are subject to risks because of registration systems that may not be subject to effective government supervision. This may result in significant delays or problems in registering the transfer of securities. Russian securities laws may not recognize foreign nominee accounts held with a custodian bank, and therefore the custodian may be considered the ultimate owner of securities they hold for their clients. Ownership of securities issued by Russian companies is recorded by companies themselves and by registrars instead of through a central registration system. It is possible that the ownership rights of the Fund could be lost through fraud or negligence. While applicable Russian regulations impose liability on registrars for losses resulting from their errors, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities in the event of loss of share registration. Adverse currency exchange rates are a risk and there may be a lack of available currency hedging instruments. Investments in Russia may be subject to the risk of nationalization or expropriation of assets. Oil, natural gas, metals, and timber account for a significant portion of Russia’s exports, leaving the country vulnerable to swings in world prices.

The Fund may invest without limit in investment grade sovereign debt denominated in the relevant country’s local currency with less than one year remaining to maturity (“short-term investment grade sovereign debt”), including short-term investment grade sovereign debt issued by emerging market issuers. The Fund may invest up to 40% of its total assets in securities and instruments that are economically tied to “emerging market” countries, other than investments in short-term investment grade sovereign debt issued by emerging market issuers, where as noted above there is no limit. PIMCO generally considers an instrument to be economically tied to an emerging market country if: the issuer is organized under the laws of an emerging market country; the currency of settlement of the security is a currency of an emerging market country; the security is guaranteed by the government of an emerging market country (or any political subdivision, agency, authority or instrumentality of such government); for an asset-backed or other collateralized security, the country in which the collateral backing the security is located is an emerging market country; or the security’s “country of exposure” is an emerging market country, as determined by the criteria set forth below.

With respect to derivative instruments, PIMCO generally considers such instruments to be economically tied to emerging market countries if the underlying assets are currencies of emerging market countries (or baskets or indexes of such currencies), or instruments or securities that are issued or guaranteed by governments of emerging market countries or by entities organized under

the laws of emerging market countries or if an instrument’s “country of exposure” is an emerging market country. A security’s “country of exposure” is determined by PIMCO using certain factors provided by a third-party analytical service provider. The factors are applied in order such that the first factor to result in the assignment of a country determines the “country of exposure.” The factors, listed in the order in which they are applied, are: (i) if an asset-backed or other collateralized security, the country in which the collateral backing the security is located; (ii) the “country of risk” of the issuer; (iii) if the security is guaranteed by the government of a country (or any political subdivision, agency, authority or instrumentality of such government), the country of the government or instrumentality providing the guarantee; (iv) the “country of risk” of the issuer’s ultimate parent, or (v) the country where the issuer is organized or incorporated under the laws thereof. “Country of risk” is a separate four-part test determined by the following factors, listed in order of importance: (i) management location, (ii) country of primary listing, (iii) sales or revenue attributable to the country, and (iv) reporting currency of the issuer. PIMCO has broad discretion to identify countries that it considers to qualify as emerging markets. In making investments in emerging market securities, the Fund emphasizes countries with relatively low gross national product per capita and with the potential for rapid economic growth. Emerging market countries are generally located in Asia, Africa, the Middle East, Latin America and Eastern Europe. PIMCO will select the country and currency composition based on its evaluation of relative interest rates, inflation rates, exchange rates, monetary and fiscal policies, trade and current account balances, and any other specific factors it believes to be relevant.

The risks of investing in non-U.S. securities are particularly high when the issuers are tied economically to countries with developing or “emerging market” economies. Countries with “emerging market” economies are those with securities markets that are, in the opinion of PIMCO, less sophisticated than more developed markets in terms of participation by investors, analyst coverage, liquidity and regulation. Investing in emerging market countries involves certain risks not typically associated with investing in U.S. securities, and imposes risks greater than, or in addition to, risks of investing in non-U.S., developed countries. These risks include: greater risks of nationalization or expropriation of assets or confiscatory taxation; currency devaluations and other currency exchange rate fluctuations; greater social, economic and political uncertainty and instability (including the risk of war); more substantial government involvement in the economy; less government supervision and regulation of the securities markets and participants in those markets; controls on foreign investment and limitations on repatriation of invested capital and on the Fund’s ability to exchange local currencies for U.S. dollars; unavailability of currency hedging techniques in certain emerging market countries; the fact that companies in emerging market countries may be smaller, less seasoned and newly organized companies; the difference in, or lack of, auditing and financial reporting standards, which may result in unavailability of material information about issuers; the risk that it may be more difficult to obtain and/or enforce a judgment in a court outside the United States; and greater price volatility, substantially less liquidity and significantly smaller market capitalization of securities markets. In addition, a number of emerging market countries restrict, to various degrees, foreign investment in securities, and high rates of inflation and rapid fluctuations in inflation rates have had, and may continue to have, negative effects on the economies and securities markets of certain emerging market countries. Also, any change in the leadership or politics of emerging market countries, or the countries that exercise a significant influence over those countries, may halt the expansion of or reverse the liberalization of foreign investment policies now occurring and adversely affect existing investment opportunities.

The Fund may also invest in Brady Bonds. Brady Bonds are securities created through the exchange of existing commercial bank loans to sovereign entities for new obligations in connection with debt restructurings under a debt restructuring plan introduced by former U.S. Secretary of the Treasury, Nicholas F. Brady (the “Brady Plan”). Brady Plan debt restructurings have been implemented in a number of countries, including: Argentina, Bolivia, Brazil, Bulgaria, Costa Rica, the Dominican Republic, Ecuador, Jordan, Mexico, Niger, Nigeria, Panama, Peru, the Philippines, Poland, Uruguay, and Venezuela.

Brady Bonds may be collateralized or uncollateralized, are issued in various currencies (primarily the U.S. dollar) and are actively traded in the OTC secondary market. Brady Bonds are not considered to be U.S. Government securities. U.S. dollar-denominated, collateralized Brady Bonds, which may be fixed rate par bonds or floating rate discount bonds, are generally collateralized in full as to principal by U.S. Treasury zero coupon bonds having the same maturity as the Brady Bonds. Interest payments on these Brady Bonds generally are collateralized on a one-year or longer rolling-forward basis by cash or securities in an amount that, in the case of fixed rate bonds, is equal to at least one year of interest payments or, in the case of floating rate bonds, initially is equal to at least one year’s interest payments based on the applicable interest rate at that time and is adjusted at regular intervals thereafter. Certain Brady Bonds are entitled to “value recovery payments” in certain circumstances, which in effect constitute supplemental interest payments but generally are not collateralized. Brady Bonds are often viewed as having three or four valuation components: (i) the collateralized repayment of principal at final maturity; (ii) the collateralized interest payments; (iii) the uncollateralized interest payments; and (iv) any uncollateralized repayment of principal at maturity (these uncollateralized amounts constitute the “residual risk”).

Most Mexican Brady Bonds issued to date have principal repayments at final maturity fully collateralized by U.S. Treasury zero coupon bonds (or comparable collateral denominated in other currencies) and interest coupon payments collateralized on an 18-month rolling-forward basis by funds held in escrow by an agent for the bondholders. A significant portion of the Venezuelan Brady Bonds and the Argentine Brady Bonds issued to date have principal repayments at final maturity collateralized by U.S. Treasury zero coupon bonds (or comparable collateral denominated in other currencies) and/or interest coupon payments collateralized on a 14-month (for Venezuela) or 12-month (for Argentina) rolling-forward basis by securities held by the Federal Reserve Bank of New York as collateral agent.

Brady Bonds involve various risk factors including residual risk and the history of defaults with respect to commercial bank loans by public and private entities of countries issuing Brady Bonds. There can be no assurance that Brady Bonds in which the Fund may invest will not be subject to restructuring arrangements or to requests for new credit, which may cause the Fund to suffer a loss of interest or principal on any of their holdings.

The Fund may purchase and sell foreign currency options and foreign currency futures contracts and related options (see “–Derivative Instruments” below), and may engage in foreign currency transactions either on a spot (cash) basis at the rate prevailing in the currency exchange market at the time or through forward currency contracts (“forwards”). The Fund may engage in these transactions in order to protect against uncertainty in the level of future foreign exchange rates in the purchase and sale of securities or because PIMCO believes a currency to which the Fund is exposed is overvalued. The Fund may also use foreign currency options, foreign currency forward contracts, foreign currency futures and foreign spot transactions to increase exposure to a foreign currency or to shift exposure to foreign currency fluctuations from one currency to another.

A forward contract involves an obligation to purchase or sell a certain amount of a specific currency at a future date, which may be any fixed number of days from the date of the contract agreed upon by the parties, at a price set at the time of the contract. These contracts may be bought or sold to protect the Fund against a possible loss resulting from an adverse change in the relationship between foreign currencies and the U.S. dollar or to increase exposure to a particular foreign currency. Open positions in forwards used for non-hedging purposes will be covered by the segregation with the Fund’s custodian of assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees, and are marked to market daily. Although forwards may be used to minimize the risk of loss due to a decline in the value of the hedged currencies, at the same time, they tend to limit any potential gain which might result should the value of such currencies increase. Forwards are used primarily to adjust the foreign exchange exposure of the Fund with a view to protecting the outlook, and the Fund might be expected to enter into such contracts under the following circumstances:

Lock In. When PIMCO desires to lock in the U.S. dollar price on the purchase or sale of a security denominated in a foreign currency.

Cross Hedge. If a particular currency is expected to decrease against another currency, the Fund may sell the currency expected to decrease and purchase a currency which is expected to increase against the currency sold in an amount approximately equal to some or all of the Fund’s exposure to the currency sold.

Direct Hedge. If PIMCO wants to eliminate substantially all of the risk of owning a particular currency, and/or if PIMCO thinks that the Fund can benefit from price appreciation in a given country’s bonds but does not want to hold the currency, it may employ a direct hedge back into the U.S. dollar. In either case, the Fund would enter into a forward contract to sell the currency to which the Fund is exposed through the security and purchase U.S. dollars at an exchange rate established at the time it initiated the contract. The cost of the direct hedge transaction may offset most, if not all, of the yield advantage offered by the foreign security, but the Fund would hope to benefit from an increase (if any) in the value of the security.

Proxy Hedge. The Fund might choose to use a proxy hedge, which may be less costly than a direct hedge. In this case, the Fund, having purchased a security, will sell a currency whose value is believed to be closely linked to the currency to which the Fund is exposed through the security. Interest rates prevailing in the country whose currency was sold would be expected to be closer to those in the United States and lower than those of securities denominated in the currency of the original holding. This type of hedging entails greater risk than a direct hedge because it is dependent on a stable relationship between the two currencies paired as proxies and the relationships can be very unstable at times.

Costs of Hedging. When the Fund purchases a foreign (non-U.S.) bond with a higher interest rate than is available on U.S. bonds of a similar maturity, the additional yield on the foreign (non-U.S.) bond could be substantially reduced or lost if the Fund were to enter into a direct hedge by selling the foreign currency and purchasing the U.S. dollar. This is what is known as the “cost” of hedging. Proxy hedging attempts to reduce this cost through an indirect hedge back to the U.S. dollar.

It is important to note that hedging costs are treated as capital transactions and are not, therefore, deducted from the Fund’s dividend distribution and are not reflected in its yield. Instead such costs will, over time, be reflected in the Fund’s net asset value per share.

The Fund may enter into foreign currency transactions as a substitute for cash investments and for other investment purposes not involving hedging, including, without limitation, to exchange payments received in a foreign currency into U.S. dollars or in anticipation of settling a transaction that requires the Fund to deliver a foreign currency.

The forecasting of currency market movement is extremely difficult, and whether any hedging strategy will be successful is highly uncertain. Moreover, it is impossible to forecast with precision the market value of portfolio securities at the expiration of a foreign currency forward contract. Accordingly, the Fund may be required to buy or sell additional currency on the spot market (and bear the expense of such transaction) if PIMCO’s predictions regarding the movement of foreign currency or securities markets prove inaccurate. Also, foreign currency transactions, like currency exchange rates, can be affected unpredictably by intervention (or the failure to intervene) by U.S. or foreign governments or central banks, or by currency controls or political developments. Such events may prevent or restrict the Fund’s ability to enter into foreign currency transactions, force the Fund to exit a foreign currency transaction at a disadvantageous time or price or result in penalties for the Fund, any of which may result in a loss to the Fund. In addition, the use of cross-hedging transactions may involve special risks, and may leave the Fund in a less advantageous position than if such a hedge had not been established. Because foreign currency forward contracts are privately negotiated transactions, there can be no assurance that the Fund will have flexibility to roll-over a foreign currency forward contract upon its expiration if it desires to do so. Additionally, there can be no assurance that the other party to the contract will perform its services thereunder. Under definitions adopted by the U.S. Commodity Futures Trading Commission (the “CFTC”) and the SEC, many non-deliverable foreign currency forwards are considered swaps for certain purposes, including determination of whether such instruments need to be exchange-traded and centrally cleared as discussed further in “Risks of Potential Government Regulation of Derivatives” and “Additional Risk Factors in Cleared Derivatives Transactions.” These changes are expected to reduce counterparty risk as compared to bi-laterally negotiated contracts.

The Fund may hold a portion of its assets in bank deposits denominated in foreign currencies, so as to facilitate investment in foreign securities as well as to protect against currency fluctuations and the need to convert such assets into U.S. dollars (thereby also reducing transaction costs). To the extent these monies are converted back into U.S. dollars, the value of the assets so maintained will be affected favorably or unfavorably by changes in foreign currency exchange rates and exchange control regulations.

Tax Consequences of Hedging and other Foreign Currency Transactions. Foreign currency gains are generally treated as qualifying income for purposes of the 90% gross income test described above. However, it is possible the IRS could issue contrary regulations with respect to foreign currency gains that are not directly related to a regulated investment company’s principal business of investing in stocks or securities (or options or futures with respect to stocks or securities), and such regulations could apply retroactively. Such regulations, if issued, could limit the ability of the Fund to enter into the foreign currency transactions described above or could bear adversely on the Fund’s ability to qualify as a regulated investment company. In addition, hedging transactions may result in the application of the mark-to-market and straddle provisions of the Code. Those provisions could affect the amount, timing or character of dividends paid by the Fund, including whether dividends paid by the Fund are classified as capital gains or ordinary income.

Foreign Currency Warrants. Foreign currency warrants such as Currency Exchange Warrants^SM are warrants which entitle the holder to receive from their issuer an amount of cash (generally, for warrants issued in the United States, in U.S. dollars) which is calculated pursuant to a predetermined formula and based on the exchange rate between a specified foreign currency and the U.S. dollar as of the exercise date of the warrant. Foreign currency warrants generally are exercisable upon their issuance and expire as of a specified date and time. Foreign currency warrants have been issued in connection with U.S. dollar-denominated debt offerings by major corporate issuers in an attempt to reduce the foreign currency exchange risk which, from the point of view of prospective purchasers of the securities, is inherent in the international fixed income marketplace. Foreign currency warrants may attempt to reduce the foreign exchange risk assumed by purchasers of a security by, for example, providing for a supplemental payment in the event that the U.S. dollar depreciates against the value of a major foreign currency such as the Japanese yen or the Euro. The formula used to determine the amount payable upon exercise of a foreign currency warrant may make the warrant worthless unless the applicable foreign currency exchange rate moves in a particular direction (e.g., unless the U.S. dollar appreciates or depreciates against the particular foreign currency to which the warrant is linked or indexed). Foreign currency warrants are severable from the debt obligations with which they may be offered, and may be listed on exchanges. Foreign currency warrants may be exercisable only in certain minimum amounts, and an investor wishing to exercise warrants who possesses less than the minimum number required for exercise may be required either to sell the warrants or to purchase additional warrants, thereby incurring additional transaction costs. In the case of any exercise of warrants, there may be a time delay between the time a holder of warrants gives instructions to exercise and the time the exchange rate relating to exercise is determined, during which time the exchange rate could change significantly, thereby affecting both the market and cash settlement values of the warrants being exercised. The expiration date of the warrants may be accelerated if the warrants should be delisted from an exchange or if their trading should be suspended permanently, which would result in the loss of any remaining “time value” of the warrants (i.e., the difference between the current market value and the exercise value of the warrants), and, in the case the warrants were “out-of-the-money,” in a total loss of the purchase price of the warrants. Warrants are generally unsecured obligations of their issuers and are not standardized foreign currency options issued by the Options Clearing Corporation (“the OCC”). Unlike foreign currency options issued by the OCC, the terms of foreign exchange warrants generally will not be amended in the event of governmental or regulatory actions affecting exchange rates or in the event of the imposition of other regulatory controls affecting the international currency markets. The initial public offering price of foreign currency warrants is generally considerably in excess of the price that a commercial user of foreign currencies might pay in the interbank market for a comparable option involving significantly larger amounts of foreign currencies. Foreign currency warrants are subject to significant foreign exchange risk, including risks arising from complex political or economic factors.

Principal Exchange Rate Linked Securities. Principal exchange rate linked securities (“PERLs^SM”) are debt obligations the principal on which is payable at maturity in an amount that may vary based on the exchange rate between the U.S. dollar and a particular foreign currency at or about that time. The return on “standard” principal exchange rate linked securities is enhanced if the foreign currency to which the security is linked appreciates against the U.S. dollar, and is adversely affected

by increases in the foreign exchange value of the U.S. dollar; “reverse” principal exchange rate linked securities are like “standard” securities, except that their return is enhanced by increases in the value of the U.S. dollar and adversely impacted by increases in the value of foreign currency. Interest payments on the securities are generally made in U.S. dollars at rates that reflect the degree of foreign currency risk assumed or given up by the purchaser of the notes (i.e., at relatively higher interest rates if the purchaser has assumed some of the foreign exchange risk, or relatively lower interest rates if the issuer has assumed some of the foreign exchange risk, based on the expectations of the current market). PERLs may in limited cases be subject to acceleration of maturity (generally, not without the consent of the holders of the securities), which may have an adverse impact on the value of the principal payment to be made at maturity.

Performance Indexed Paper. Performance indexed paper is U.S. dollar-denominated commercial paper the yield of which is linked to certain foreign exchange rate movements. The yield to the investor on performance indexed paper is established at maturity as a function of spot exchange rates between the U.S. dollar and a designated currency as of or about that time (generally, the index maturity two days prior to maturity). The yield to the investor will be within a range stipulated at the time of purchase of the obligation, generally with a guaranteed minimum rate of return that is below, and a potential maximum rate of return that is above, market yields on U.S. dollar-denominated commercial paper, with both the minimum and maximum rates of return on the investment corresponding to the minimum and maximum values of the spot exchange rate two business days prior to maturity.

U.S. Government securities are obligations of, and, in certain cases, guaranteed by, the U.S. Government, its agencies or instrumentalities. The U.S. Government does not guarantee the net asset value of the Fund’s shares. U.S. Government securities are subject to market and interest rate risk, and may be subject to varying degrees of credit risk. Some U.S. Government securities, such as Treasury bills, notes and bonds, and securities guaranteed by GNMA, are supported by the full faith and credit of the United States; others, such as those of the Federal Home Loan Banks, are supported by the right of the issuer to borrow from the U.S. Treasury; others, such as those of the FNMA, are supported by the discretionary authority of the U.S. Government to purchase the agency’s obligations; and still others, such as securities issued by members of the Farm Credit System, are supported only by the credit of the agency, instrumentality or corporation.

Securities issued by U.S. Government agencies or government-sponsored enterprises may not be guaranteed by the U.S. Treasury. 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 VA. Government-related guarantors (i.e., not backed by the full faith and credit of the U.S. Government) include the FNMA and the Federal Home Loan Mortgage Corporation (“FHLMC”). Pass-through securities issued by FNMA are guaranteed as to timely payment of principal and interest by FNMA but are not backed by the full faith and credit of the U.S. Government. FHLMC guarantees the timely payment of interest and ultimate collection of principal, but its participation certificates are not backed by the full faith and credit of the U.S. Government.

U.S. Government securities include securities that have no coupons, or have been stripped of their unmatured interest coupons, individual interest coupons from such securities that trade separately, and evidences of receipt of such securities. Such securities may pay no cash income, and are purchased at a deep discount from their value at maturity. Because interest on zero coupon securities is not distributed on a current basis but is, in effect, compounded, zero coupon securities tend to be subject to greater risk than interest-paying securities of similar maturities. Custodial receipts issued in connection with so-called trademark zero coupon securities, such as CATs and TIGRs, are not issued by the U.S. Treasury, and are therefore not U.S. Government securities, although the underlying bond represented by such receipt is a debt obligation of the U.S. Treasury. Other zero coupon Treasury securities (e.g., STRIPs and CUBEs) are direct obligations of the U.S. Government.

The Fund may invest in securities issued by states, territories, possessions, municipalities and other political subdivisions, agencies, authorities and instrumentalities of states, territories, possessions and multi-state agencies or authorities.

Municipal Securities. Municipal securities include debt obligations issued by governmental entities to obtain funds for various public purposes, including the construction of a wide range of public facilities, the refunding of outstanding obligations, the payment of general operating expenses, and the extension of loans to public institutions and facilities. Municipal securities can be classified into two principal categories, including “general obligation” bonds and other securities and “revenue” bonds and other securities. General obligation bonds are secured by the issuer’s full faith, credit and taxing power for the payment of principal and interest. Revenue securities are payable only from the revenues derived from a particular facility or class of facilities or, in some cases, from the proceeds of a special excise tax or other specific revenue source, such as the user of the facility being financed. Municipal securities also may include “moral obligation” securities, which normally are issued by special purpose public authorities. If the issuer of moral obligation securities is unable to meet its debt service obligations from current revenues, it may draw on a reserve fund, the restoration of which is a moral commitment but not a legal obligation of the governmental entity that created the special purpose public authority. Municipal securities may be structured as fixed-, variable- or floating-rate obligations or as zero-coupon, PIKs and step-coupon securities and may be privately placed or publicly offered.

Municipal securities may include municipal bonds, municipal notes and municipal leases. Municipal bonds are debt obligations of a governmental entity that obligate the municipality to pay the holder a specified sum of money at specified intervals and to repay the principal amount of the loan at maturity.

The Fund may invest in municipal lease obligations. A lease is not a full faith and credit obligation of the issuer and is usually backed only by the borrowing government’s unsecured pledge to make annual appropriations for lease payments. There have been challenges to the legality of lease financing in numerous states, and, from time to time, certain municipalities have considered not appropriating money for lease payments. In deciding whether to purchase a lease obligation for the Fund, PIMCO will assess the financial condition of the borrower, the merits of the project, the level of public support for the project and the legislative history of lease financing in the state. These securities may be less readily marketable than other municipal securities.

Municipal notes may be issued by governmental entities and other tax-exempt issuers in order to finance short-term cash needs or, occasionally, to finance construction. Most municipal notes are general obligations of the issuing entity payable from taxes or designated revenues expected to be received within the relevant fiscal period. Municipal notes generally have maturities of one year or less. Municipal notes can be subdivided into two sub-categories: (i) municipal commercial paper and (ii) municipal demand obligations. Municipal commercial paper typically consists of very short-term unsecured negotiable promissory notes that are sold, for example, to meet seasonal working capital or interim construction financing needs of a governmental entity or agency. While these obligations are intended to be paid from general revenues or refinanced with long-term debt, they frequently are backed by letters of credit, lending agreements, note repurchase agreements or other credit facility agreements offered by banks or institutions.

Municipal demand obligations can be subdivided into two general types: variable rate demand notes and master demand obligations. Variable rate demand notes are tax-exempt municipal obligations or participation interests that provide for a periodic adjustment in the interest rate paid on the notes. They permit the holder to demand payment of the notes, or to demand purchase of the notes at a purchase price equal to the unpaid principal balance, plus accrued interest either directly by the issuer or by drawing on a bank letter of credit or guaranty issued with respect to such note. The issuer of the municipal obligation may have a corresponding right to prepay at its discretion the outstanding principal of the note plus accrued interest upon notice comparable to that required for the holder to demand payment. The variable rate demand notes in which the Fund may invest are payable, or are subject to purchase, on demand usually on notice of seven calendar days or less. The terms of the notes generally provide that interest rates are adjustable at intervals ranging from daily to six months.

Master demand obligations are tax-exempt municipal obligations that provide for a periodic adjustment in the interest rate paid and permit daily changes in the amount borrowed. The interest on such obligations is, in the opinion of counsel for the borrower, excluded from gross income for federal income tax purposes (but not necessarily for alternative minimum tax purposes). Although there is no secondary market for master demand obligations, such obligations are considered by the Fund to be liquid because they are payable upon demand.

Investing in municipal securities is subject to certain risks. There are variations in the quality of municipal securities, both within a particular classification and between classifications, and the rates of return on municipal securities can depend on a variety of factors, including general money market conditions, the financial condition of the issuer, general conditions of the municipal bond market, the size of a particular offering, the maturity of the obligation, and the rating of the issue. The ratings of NRSROs represent their opinions as to the quality of municipal securities. It should be emphasized, however, that these ratings are general and are not absolute standards of quality, and municipal securities with the same maturity, interest rate, and rating may have different rates of return while municipal securities of the same maturity and interest rate with different ratings may have the same rate of return.

The payment of principal and interest on most municipal securities purchased by the Fund will depend upon the ability of the issuers to meet their obligations. An issuer’s obligations under its municipal securities are subject to the provisions of bankruptcy, insolvency, and other laws affecting the rights and remedies of creditors, such as the United States Bankruptcy Code. The power or ability of an issuer to meet its obligations for the payment of interest on and principal of its municipal securities may be materially adversely affected by litigation or other conditions.

There are particular considerations and risks relevant to investing in a portfolio of a single state’s municipal securities, such as the greater risk of the concentration of portfolio holdings. Each state’s municipal securities may include, in addition to securities issued by the relevant state and its political subdivisions, agencies, authorities and instrumentalities, securities issued by the governments of Guam, Puerto Rico or the U.S. Virgin Islands. These securities may be subject to different risks than municipal securities issued by the relevant state and its political subdivisions, agencies, authorities and instrumentalities.

The Fund ordinarily purchases municipal securities whose interest, in the opinion of bond counsel, is excluded from gross income for federal income tax purposes. The opinion of bond counsel may assert that such interest is not an item of tax preference for the purposes of the alternative minimum tax or is exempt from certain state or local taxes. There is no assurance that the applicable taxing authority will agree with this opinion. In the event, for example, the

Internal Revenue Service (“IRS”) determines that an issuer does not comply with relevant tax requirements, interest payments from a security could become federally taxable, possibly retroactively to the date the security was issued. As a shareholder of the Fund, you may be required to file an amended tax return as a result, reporting such income as taxable.

Municipal Bonds. Municipal bonds share the attributes of debt/fixed income securities in general, but are generally issued by states, municipalities and other political subdivisions, agencies, authorities and instrumentalities of states and multi-state agencies or authorities. The municipal bonds that the Fund may purchase include general obligation bonds and limited obligation bonds (or revenue bonds), including industrial development bonds issued pursuant to former federal tax law. General obligation bonds are obligations involving the credit of an issuer possessing taxing power and are payable from such issuer’s general revenues and not from any particular source. Limited obligation bonds are payable only from the revenues derived from a particular facility or class of facilities or, in some cases, from the proceeds of a special excise or other specific revenue source. Tax-exempt private activity bonds and industrial development bonds generally are also revenue bonds and thus are not payable from the issuer’s general revenues. The credit and quality of private activity bonds and industrial development bonds are usually related to the credit of the corporate user of the facilities. Payment of interest on and repayment of principal of such bonds is the responsibility of the user and any guarantor. The Fund does not expect to be eligible to pass through to shareholders the tax-exempt character of interest earned on municipal bonds. The Fund may be more sensitive to adverse economic, business or political developments if it invests a substantial portion of its assets in industrial development bonds.

The Fund may invest in pre-refunded municipal bonds. Pre-refunded municipal bonds are tax exempt bonds that have been refunded to a call date prior to the final maturity of principal, or, in the case of pre-refunded municipal bonds commonly referred to as “escrowed-to-maturity bonds,” to the final maturity of principal, and remain outstanding in the municipal market. The payment of principal and interest of the pre-refunded municipal bonds held by the Fund is funded from securities in a designated escrow account that holds U.S. Treasury securities or other obligations of the U.S. Government (including its agencies and instrumentalities (“Agency Securities”)). Interest payments on pre-refunded municipal bonds issued on or prior to December 31, 2017 are exempt from federal income tax; pre-refunded municipal bonds issued after December 31, 2017 will not qualify for such tax-advantaged treatment. As the payment of principal and interest is generated from securities held in an escrow account established by the municipality and an independent escrow agent, the pledge of the municipality has been fulfilled and the original pledge of revenue by

the municipality is no longer in place. The escrow account securities pledged to pay the principal and interest of the pre-refunded municipal bond do not guarantee the price movement of the bond before maturity. Issuers of municipal bonds refund in advance of maturity the outstanding higher cost debt and issue new, lower cost debt, placing the proceeds of the lower cost issuance into an escrow account to pre-refund the older, higher cost debt. Investments in pre-refunded municipal bonds held by the Fund may subject the Fund to interest rate risk, market risk and credit risk. In addition, while a secondary market exists for pre-refunded municipal bonds, if the Fund sells pre-refunded municipal bonds prior to maturity, the price received may be more or less than the original cost, depending on market conditions at the time of sale. To the extent permitted by the SEC and the IRS, the Fund’s investment in pre-refunded municipal bonds backed by U.S. Treasury and Agency securities in the manner described above, will, for purposes of diversification tests applicable to the Fund, be considered an investment in the respective U.S. Treasury and Agency securities.

Under the Code, certain limited obligation bonds are considered “private activity bonds” and interest paid on such bonds is treated as an item of tax preference for purposes of calculating federal alternative minimum tax liability.

Economic downturns and budgetary constraints have made municipal bonds more susceptible to downgrade, default and bankruptcy. In addition, difficulties in the municipal bond markets could result in increased illiquidity, volatility and credit risk, and a decrease in the number of municipal bond investment opportunities. The value of municipal bonds may also be affected by uncertainties involving the taxation of municipal bonds or the rights of municipal bond holders in the event of a bankruptcy. Proposals to restrict or eliminate the federal income tax exemption for interest on municipal bonds are introduced before Congress from time to time. These legal uncertainties could affect the municipal bond market generally, certain specific segments of the market, or the relative credit quality of particular securities.

The Fund may purchase and sell portfolio investments to take advantage of changes or anticipated changes in yield relationships, markets or economic conditions. The Fund may also sell municipal bonds due to changes in PIMCO’s evaluation of the issuer. The secondary market for municipal bonds typically has been less liquid than that for taxable debt/fixed income securities, and this may affect the Fund’s ability to sell particular municipal bonds at then-current market prices, especially in periods when other investors are attempting to sell the same securities.

Additionally, municipal bonds rated below investment grade (i.e., high yield municipal bonds) may not be as liquid as higher-rated municipal bonds. Reduced liquidity in the secondary market may have an adverse impact on the market price of a municipal bond and on the Fund’s ability to sell a municipal bond in response to changes or anticipated changes in economic conditions or to meet the Fund’s cash needs. Reduced liquidity may also make it more difficult to obtain market quotations based on actual trades for purposes of valuing the Fund’s portfolio. For more information on high yield securities please see “High Yield Securities (“Junk Bonds”) and Securities of Distressed Companies” above.

Prices and yields on municipal bonds are dependent on a variety of factors, including general money-market conditions, the financial condition of the issuer, general conditions of the municipal bond market, the size of a particular offering, the maturity of the obligation and the rating of the issue. A number of these factors, including the ratings of particular issues, are subject to change from time to time. Information about the financial condition of an issuer of municipal bonds may not be as extensive as that which is made available by corporations whose securities are publicly traded.

The perceived increased likelihood of default among issuers of municipal bonds has resulted in constrained illiquidity, increased price volatility and credit downgrades of issuers of municipal bonds. Local and national market forces—such as declines in real estate prices and general business activity—may result in decreasing tax bases, fluctuations in interest rates, and increasing construction costs, all of which could reduce the ability of certain issuers of municipal bonds to repay their obligations. Certain issuers of municipal bonds have also been unable to obtain additional financing through, or must pay higher interest rates on, new issues, which may reduce revenues available for issuers of municipal bonds to pay existing obligations. In addition, events have demonstrated that the lack of disclosure rules in this area can make it difficult for investors to obtain reliable information on the obligations underlying municipal bonds. Adverse developments in the municipal bond market may negatively affect the value of all or a substantial portion of the Fund’s holdings in municipal bonds.

Obligations of issuers of municipal bonds are subject to the provisions of bankruptcy, insolvency and other laws affecting the rights and remedies of creditors. Congress or state legislatures may seek to extend the time for payment of principal or interest, or both, or to impose other constraints upon enforcement of such obligations. There is also the possibility that as a result of litigation or other conditions, the power or ability of issuers to meet their obligations for the payment of interest and principal on their municipal bonds may be materially affected or their obligations may be found to be invalid or unenforceable. Such litigation or conditions may from time to time have the effect of introducing uncertainties in the market for municipal bonds or certain segments thereof, or of materially affecting the credit risk with respect to particular bonds. Adverse economic, business, legal or political developments might affect all or a substantial portion of the Fund’s municipal bonds in the same manner.

From time to time, proposals have been introduced before Congress for the purpose of restricting or eliminating the federal income tax exemption for interest on certain types of municipal bonds. Additionally, certain other proposals have been introduced that would have the effect of taxing a portion of exempt interest and/or reducing the tax benefits of receiving exempt interest. It can be expected that similar proposals may be introduced in the future. As a result of any such future legislation, the availability of such municipal bonds for investment by the Fund and the value of such municipal bonds held by the Fund may be affected. In addition, it is possible that events occurring after the date of a municipal bond’s issuance, or after the Fund’s acquisition of such obligation, may result in a determination that the interest paid on that obligation is taxable, in certain cases retroactively.

Some longer-term municipal bonds give the investor the right to “put” or sell the security at par (face value) within a specified number of days following the investor’s request—usually one to seven days. This demand feature enhances a security’s liquidity by shortening its effective maturity and enables it to trade at a price equal to or very close to par. If a demand feature terminates prior to being exercised, the Fund would hold the longer-term security, which could experience substantially more volatility.

The Fund may invest in taxable municipal bonds, such as Build America Bonds. Build America Bonds are tax credit bonds created by the American Recovery and Reinvestment Act of 2009, which authorized state and local governments to issue Build America Bonds as taxable bonds in

2009 and 2010, without volume limitations, to finance any capital expenditures for which such issuers could otherwise issue traditional tax-exempt bonds. State and local governments may receive a direct federal subsidy payment for a portion of their borrowing costs on Build America Bonds equal to 35% of the total coupon interest paid to investors (or 45% in the case of Recovery Zone Economic Development Bonds). The state or local government issuer can elect to either take the federal subsidy or pass the 35% tax credit along to bondholders. The Fund’s investments in Build America Bonds or similar taxable municipal bonds will result in taxable income and the Fund may elect to pass through to holders of the Fund’s Common Shares (“Common Shareholders”) the corresponding tax credits. The tax credits can generally be used to offset federal income taxes and the alternative minimum tax, but such credits are generally not refundable. Build America Bonds or similar taxable municipal bonds involve similar risks as tax-exempt municipal bonds, including credit and market risk. They are intended to assist state and local governments in financing capital projects at lower borrowing costs and are likely to attract a broader group of investors than tax-exempt municipal bonds. Although Build America Bonds were only authorized for issuance during 2009 and 2010, the program may have resulted in reduced issuance of tax-exempt municipal bonds during the same period.

The Build America Bond program expired on December 31, 2010, at which point no further issuance of new Build America Bonds was permitted. As of the date of this Statement of Additional Information, there is no indication that Congress will renew the program to permit issuance of new Build America Bonds.

Puerto Rico Municipal Securities. Municipal obligations issued by the Commonwealth of Puerto Rico or its political subdivisions, agencies, instrumentalities, or public corporations may be affected by economic, market, political, and social conditions in Puerto Rico. Puerto Rico currently is experiencing significant fiscal and economic challenges, including substantial debt service obligations, high levels of unemployment, underfunded public retirement systems, and persistent government budget deficits. These challenges may negatively affect the value of the Fund’s investments in Puerto Rico municipal securities. Major ratings agencies have downgraded the general obligation debt of Puerto Rico to below investment grade and continue to maintain a negative outlook for this debt, which increases the likelihood that the rating will be lowered further. In both August 2015 and January 2016, Puerto Rico defaulted on its debt by failing to make full payment due on its outstanding bonds, and there can be no assurance that Puerto Rico will be able to satisfy its future debt obligations. Further downgrades or defaults may place additional strain on the Puerto Rico economy and may negatively affect the value, liquidity, and volatility of the Fund’s investments in Puerto Rico municipal securities. Legislation, including legislation that would allow Puerto Rico to restructure its municipal debt obligations, thus increasing the risk that Puerto Rico may never pay off municipal indebtedness, or may pay only a small fraction of the amount owed, could also impact the value of the Fund’s investments in Puerto Rico municipal securities.

These challenges and uncertainties have been exacerbated by Hurricane Maria and the resulting natural disaster in Puerto Rico. In September 2017, Hurricane Maria struck Puerto Rico, causing major damage across the Commonwealth, including damage to its water, power, and telecommunications infrastructure. The length of time needed to rebuild Puerto Rico’s infrastructure is unclear, but could amount to years, during which the Commonwealth is likely to be in an uncertain economic state. The full extent of the natural disaster’s impact on Puerto Rico’s economy and foreign investment in Puerto Rico is difficult to estimate.

The Fund normally invests at least 25% of its total assets in corporate debt obligations and other corporate income-producing securities. The Fund may invest in corporate debt securities of U.S. issuers and foreign issuers, and/or it may hold its assets in these securities for cash management purposes. The investment return of corporate debt securities reflects interest earnings and changes in the market value of the security. The market value of a corporate debt obligation may be expected to rise and fall inversely with interest rates generally. There also exists the risk that the issuers of the securities may not be able to meet their obligations on interest or principal payments at the time called for by an instrument. The Fund’s investments in U.S. dollar or

foreign currency-denominated corporate debt securities of domestic or foreign issuers are limited to corporate debt securities (corporate bonds, debentures, notes and other similar corporate debt instruments, including convertible securities) which meet the minimum ratings criteria set forth for the Fund, or, if unrated, are in PIMCO’s opinion comparable in quality to corporate debt securities in which the Fund may invest. Corporate income-producing securities may include forms of preferred or preference stock. The rate interest on a corporate debt security may be fixed, floating or variable, and may vary inversely with respect to a reference rate. The rate of return or return of principal on some debt obligations may be linked or indexed to the level of exchange rates between the U.S. dollar and a foreign currency or currencies. Corporate debt securities may be acquired with warrants attached. Securities rated Baa by Moody’s, BBB by S&P and BBB by Fitch are the lowest which are considered “investment grade” obligations. Moody’s describes securities rated Baa as “medium-grade” obligations; they are subject to moderate credit risk and as such may possess certain speculative characteristics. S&P describes securities rated BBB as “having adequate capacity to meet financial commitments, however, adverse economic conditions or changing circumstances are more likely to lead to a weakened capacity of the obligor to meet its financial commitments.” For securities rated BBB, Fitch states that “.... expectations of default risk are currently low... capacity for payment of financial commitments is considered adequate, but adverse business or economic conditions are more likely to impair this capacity.” For a discussion of securities rated below investment grade, see “High Yield Securities (“Junk Bonds”) and Securities of Distressed Companies” above.

Commercial paper represents short-term unsecured promissory notes issued in bearer form by corporations such as banks or bank holding companies and finance companies. The Fund may invest in commercial paper of any credit quality consistent with the Fund’s investment objective and policies, including unrated commercial paper for which PIMCO has made a credit quality assessment. See Appendix A to the Prospectus for a description of the ratings assigned by Moody’s, S&P and Fitch Ratings to commercial paper. The rate of return on commercial paper may be linked or indexed to the level of exchange rates between the U.S. dollar and a foreign currency or currencies.

The Fund may invest in convertible securities, which may offer higher income than the common stocks into which they are convertible. A convertible debt security is a bond, debenture, note, or other security that entitles the holder to acquire common stock or other equity securities of the same or a different issuer. A convertible security generally entitles the holder to receive interest paid or

accrued until the convertible security matures or is redeemed, converted or exchanged. Before conversion, convertible securities have characteristics similar to non-convertible debt securities or preferred securities. Convertible securities rank senior to common stock in a corporation’s capital structure and, therefore, generally entail less risk than the corporation’s common stock, although the extent to which such risk is reduced depends in large measure upon the degree to which the convertible security sells above its value as a fixed income security. Convertible securities are subordinate in rank to any senior debt obligations of the issuer, and, therefore, an issuer’s convertible securities entail more risk than its debt obligations. Convertible securities generally offer lower interest or dividend yields than non-convertible debt securities of similar credit quality because of the potential for capital appreciation. In addition, convertible securities are often lower-rated securities.

Because of the conversion feature, the price of the convertible security will normally fluctuate in some proportion to changes in the price of the underlying asset, and as such is subject to risks relating to the activities of the issuer and/or general market and economic conditions. The income component of a convertible security may tend to cushion the security against declines in the price of the underlying asset. However, the income component of convertible securities causes fluctuations based upon changes in interest rates and the credit quality of the issuer. If the convertible security’s “conversion value,” which is the market value of the underlying common stock that would be obtained upon the conversion of the convertible security, is substantially below the “investment value,” which is the value of a convertible security viewed without regard to its conversion feature (i.e., strictly on the basis of its yield), the price of the convertible security is typically governed principally by its investment value. If the conversion value of a convertible security increases to a point that approximates or exceeds its investment value, the value of the security will typically be principally influenced by its conversion value. A convertible security generally sells at a premium over its conversion value to the extent investors place value on the right to acquire the underlying common stock while holding an income-producing security.

A convertible security may be subject to redemption at the option of the issuer at a predetermined price. If a convertible security held by the Fund is called for redemption, the Fund would be required to permit the issuer to redeem the security and convert it to underlying common stock, or would sell the convertible security to a third party, which may have an adverse effect on the Fund’s ability to achieve its investment objective. The Fund generally would invest in convertible securities for their favorable price characteristics and total return potential and would normally not exercise an option to convert unless the security is called or conversion is forced.

The Fund may invest in so-called “synthetic convertible securities,” which are composed of two or more different securities whose investment characteristics, taken together, resemble those of convertible securities. A third party or PIMCO may create a “synthetic” convertible security by combining separate securities that possess the two principal characteristics of a traditional convertible security, i.e., an income-producing security (“income-producing component”) and the right to acquire an equity security (“convertible component”). The income-producing component is achieved by investing in non-convertible, income-producing securities such as bonds, preferred securities and money market instruments, which may be represented by derivative instruments. The convertible component is achieved by investing in securities or instruments such as warrants or options to buy common stock at a certain exercise price, or options on a stock index. Unlike a traditional convertible security, which is a single security having a unitary market value, a synthetic convertible comprises two or more separate securities, each with its own market value. Therefore, the “market value” of a synthetic convertible security is the sum of the values of its income-producing component and its convertible component. For this reason, the values of a synthetic convertible security and a traditional convertible security may respond differently to market fluctuations.

More flexibility is possible in the assembly of a synthetic convertible security than in the purchase of a convertible security. Although synthetic convertible securities may be selected where the two components are issued by a single issuer, thus making the synthetic convertible security similar to the traditional convertible security, the character of a synthetic convertible security allows the combination of components representing distinct issuers, when PIMCO believes that such a combination may better achieve the Fund’s investment objective. A synthetic convertible security also is a more flexible investment in that its two components may be purchased separately. For example, the Fund may purchase a warrant for inclusion in a synthetic convertible security but temporarily hold short-term investments while postponing the purchase of a corresponding bond pending development of more favorable market conditions.

A holder of a synthetic convertible security faces the risk of a decline in the price of the security or the level of the index or security involved in the convertible component, causing a decline in the value of the security or instrument, such as a call option or warrant purchased to create the synthetic convertible security. Should the price of the stock fall below the exercise price and remain there throughout the exercise period, the entire amount paid for the call option or warrant would be lost. Because a synthetic convertible security includes the income-producing component as well, the holder of a synthetic convertible security also faces the risk that interest rates will rise, causing a decline in the value of the income-producing component.

The Fund also may purchase synthetic convertible securities created by other parties, including convertible structured notes. Convertible structured notes are income-producing debentures linked to equity, and are typically issued by investment banks. Convertible structured notes have the attributes of a convertible security; however, the investment bank that issues the convertible note, rather than the issuer of the underlying common stock into which the note is convertible, assumes credit risk associated with the underlying investment, and the Fund in turn assumes credit risk associated with the convertible note.

Contingent Convertible Instruments. Contingent convertible securities (“CoCos”) are a form of hybrid debt security issued primarily by non-U.S. issuers, which have loss absorption mechanisms built into their terms. CoCos have no stated maturity, have fully discretionary coupons and are typically issued in the form of subordinated debt instruments. CoCos generally either convert into common stock of the issuer or have their principal written down upon the occurrence of certain triggering events (“triggers”) linked to regulatory capital thresholds or regulatory actions calling into question the issuing banking institution’s continued viability as a going-concern. In certain scenarios, investors in CoCos may suffer a loss of capital ahead of equity holders or when equity holders do not. There is no guarantee that the Fund will receive a return of principal on CoCos. Any indication that an automatic write-down or conversion event may occur can be expected to have an adverse effect on the market price of CoCos. CoCos are often rated below investment grade and are subject to the risks of high yield securities. Because CoCos are issued primarily by financial institutions, CoCos may present substantially increased risks at times of financial turmoil, which could affect financial institutions more than companies in other sectors and industries. Further, the value of an investment in CoCos is unpredictable and will be influenced by many factors and risks, including interest rate risk, credit risk, market risk and liquidity risk. An investment by the Fund in CoCos may result in losses to the Fund.

Loss absorption risk. CoCos may be subject to an automatic write-down (i.e., the automatic write-down of the principal amount or value of the securities, potentially to zero, and the cancellation of the securities) under certain circumstances, which could result in the Fund losing a portion or all of its investment in such securities. In addition, the Fund may not have any rights with respect to repayment of the principal amount of the securities that has not become due or the payment of interest or dividends on such securities for any period from (and including) the interest or dividend payment date falling immediately prior to the occurrence of such automatic write-down. An automatic write-down could also result in a reduced income rate if the dividend or interest payment is based on the security’s par value. In addition, CoCos have fully discretionary coupons. This means coupons can potentially be cancelled at the issuer’s discretion or at the request of the relevant regulatory authority in order to help the issuer absorb losses and may be suspended in the event there are insufficient distributable reserves.

Subordinated instruments. CoCos will, in the majority of circumstances, be issued in the form of subordinated debt instruments in order to provide the appropriate regulatory capital treatment prior to a conversion. Accordingly, in the event of liquidation, dissolution or winding-up of an issuer prior to a conversion having occurred, the rights and claims of the holders of the CoCos, such as the Fund, against the issuer in respect of or arising under the terms of the CoCos shall generally rank junior to the claims of all holders of unsubordinated obligations of the issuer. In addition, if the CoCos are converted into the issuer’s underlying equity securities following a conversion event (i.e., a “trigger”), each holder will be subordinated due to their conversion from being the holder of a debt instrument to being the holder of an equity instrument.

Market value will fluctuate based on unpredictable factors. The trading behavior of a given issuer’s CoCos may be strongly impacted by the trading behavior of other issuers’ CoCos, such that negative information from an unrelated CoCo may cause a decline in value of one or more CoCos held by the Fund. Accordingly, the trading behavior of CoCos may not follow the trading behavior of other similarly structured securities. The value of CoCos is unpredictable and could be influenced by many factors including, without limitation: (i) the creditworthiness of the issuer and/or fluctuations in such issuer’s applicable capital ratios; (ii) supply and demand for the CoCos; (iii) general market conditions and available liquidity; and (iv) economic, financial and political events that affect the issuer, its particular market or the financial markets in general.

The Fund may invest up to 20% of its total assets in common stocks and other equity securities from time to time, including those it has received through the conversion of a convertible security held by the Fund or in connection with the restructuring of a debt security. The market price of common stocks and other equity securities may go up or down, sometimes rapidly or unpredictably. Equity securities may decline in value due to factors affecting equity securities markets generally, particular industries represented in those markets, or the issuer itself. The values of equity securities may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally.

They may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. Equity securities generally have greater price volatility than fixed-income securities. These risks are generally magnified in the case of equity investments in distressed companies.

Preferred securities represent an equity interest in a company that generally entitles the holder to receive, in preference to the holders of other stocks such as common stocks, dividends and a fixed share of the proceeds resulting from a liquidation of the company. Some preferred securities also entitle their holders to receive additional liquidation proceeds on the same basis as holders of a company’s common stock, and thus also represent an ownership interest in that company. Preferred securities are subject to issuer-specific and market risks applicable generally to equity securities. The value of a company’s preferred securities may fall as a result of factors relating directly to that company’s products or services. A preferred security’s value may also fall because of factors affecting not just the company, but companies in the same industry or in a number of different industries, such as increases in production costs. The value of preferred securities may also be affected by changes in financial markets that are relatively unrelated to the company or its industry, such as changes in interest rates or currency exchange rates. In addition, a company’s preferred securities generally pay dividends only after the company makes required payments to holders of its bonds and other debt. For this reason, the value of preferred securities will usually react more strongly than bonds and other debt to actual or perceived changes in the company’s financial condition or prospects. Preferred securities of smaller companies may be more vulnerable to adverse developments than those of larger companies.

Adjustable Rate and Auction Preferred Securities. Typically, the dividend rate on an adjustable rate preferred security is determined prospectively each quarter by applying an adjustment formula established at the time of issuance of the security. Although adjustment formulas vary among issues, they typically involve a fixed premium or discount relative to rates on specified debt securities issued by the U.S. Treasury. Typically, an adjustment formula will provide for a fixed premium or discount adjustment relative to the highest base yield of three specified U.S. Treasury securities: the 90-day Treasury bill, the 10-year Treasury note and the 20-year Treasury bond. The premium or discount adjustment to be added to or subtracted from this highest U.S. Treasury base rate yield is fixed at the time of issue and cannot be changed without the approval of the holders of the security. The dividend rate on another type of preferred security in which the Fund may invest, commonly known as auction preferred securities, is adjusted at intervals that may be more frequent than quarterly, such as every 7 or 49 days, based on bids submitted by holders and prospective purchasers of such securities and may be subject to stated maximum and minimum dividend rates. The issues of most adjustable rate and auction preferred securities currently outstanding are perpetual, but are redeemable after a specified date, or upon notice, at the option of the issuer. Certain issues supported by the credit of a high-rated financial institution provide for mandatory redemption prior to expiration of the credit arrangement. No redemption can occur if full cumulative dividends are not paid. Although the dividend rates on adjustable and auction preferred securities are generally adjusted or reset frequently, the market values of these preferred securities may still fluctuate in response to changes in interest rates. Market values of adjustable preferred securities also may substantially fluctuate if interest rates increase or decrease once the maximum or minimum dividend rate for a particular security is approached. Auctions for U.S. auction preferred securities have failed since early 2008, and the dividend rates payable on such preferred securities since that time typically have been paid at their maximum applicable rate (typically a function of a

reference rate of interest). PIMCO expects that auction preferred securities will continue to pay dividends at their maximum applicable rate for the foreseeable future and cannot predict whether or when the auction markets for auction preferred securities may resume normal functioning.

Fixed Rate Preferred Securities. Some fixed rate preferred securities in which the Fund may invest, known as perpetual preferred securities, offer a fixed return with no maturity date. Because they never mature, perpetual preferred securities act like long-term bonds and can be more volatile than and more sensitive to changes in interest rates than other types of preferred securities that have a maturity date. The Fund may also invest in sinking fund preferred securities. These preferred securities also offer a fixed return, but have a maturity date and are retired or redeemed on a predetermined schedule. The shorter duration of sinking fund preferred securities makes them perform somewhat like intermediate-term bonds and they typically have lower yields than perpetual preferred securities.

The Fund may invest in bank capital securities of both non-U.S. (foreign) and U.S. issuers. Bank capital securities are issued by banks to help fulfill their regulatory capital requirements. There are three common types of bank capital: Lower Tier II, Upper Tier II and Tier I. Bank capital is generally, but not always, of investment grade quality. Upper Tier II securities are commonly thought of as hybrids of debt and preferred stock. Upper Tier II securities are often perpetual (with no maturity date), callable and have a cumulative interest deferral feature. This means that under certain conditions, the issuer bank can withhold payment of interest until a later date. However, such deferred interest payments generally earn interest. Tier I securities often take the form of trust preferred securities. Subject to the Fund’s limitation on concentration of more than 25% of its net assets in the securities of issuers in a particular industry, the Fund may invest without limit in U.S. dollar-denominated obligations of foreign banks and up to 25% of its total assets in foreign bank obligations denominated in foreign currencies.

Bank obligations in which the Fund may invest include, without limitation, certificates of deposit, bankers’ acceptances and fixed time deposits. Certificates of deposit are negotiable certificates that are issued against funds deposited in a commercial bank for a definite period of time and that earn a specified return. Bankers’ acceptances are negotiable drafts or bills of exchange, normally drawn by an importer or exporter to pay for specific merchandise, which are “accepted” by a bank, meaning, in effect, that the bank unconditionally agrees to pay the face value of the instrument on maturity. Fixed time deposits are bank obligations payable at a stated maturity date and bearing interest at a fixed rate. Fixed time deposits may be withdrawn on demand by the investor, but may be subject to early withdrawal penalties which vary depending upon market conditions and the remaining maturity of the obligation. There are generally no contractual restrictions on the right to transfer a beneficial interest in a fixed time deposit to a third party, although there is generally no market for such deposits.

The activities of U.S. banks and most foreign banks are subject to comprehensive regulations which, in the case of U.S. regulations, have undergone substantial changes in the past decade and are currently subject to legislative and regulatory scrutiny. The enactment of new legislation or regulations, as well as changes in interpretation and enforcement of current laws, may affect the manner of operations and profitability of U.S. and foreign banks. Significant developments in the U.S. banking industry have included increased competition from other types of financial institutions, increased acquisition activity and geographic expansion. Banks may be particularly

susceptible to certain economic factors, such as interest rate changes and adverse developments in the market for real estate. Fiscal and monetary policy and general economic cycles can affect the availability and cost of funds, loan demand and asset quality and thereby impact the earnings and financial conditions of banks.

Obligations of foreign banks involve somewhat different investment risks than those affecting obligations of U.S. banks, including the possibilities that their liquidity could be impaired because of future political and economic developments, that their obligations may be less marketable than comparable obligations of U.S. banks, that a foreign jurisdiction might impose withholding taxes on interest income payable on those obligations, that foreign deposits may be seized or nationalized, that foreign governmental restrictions such as exchange controls may be adopted which might adversely affect the payment of principal and interest on those obligations and that the selection of those obligations may be more difficult because there may be less publicly available information concerning foreign banks and the accounting, auditing and financial reporting standards, practices and requirements applicable to foreign banks may differ from those applicable to U.S. banks. Foreign banks are not generally subject to examination by any U.S. Government agency or instrumentality.

The Fund may purchase indebtedness and participations in commercial loans, as well as interests and/or servicing or similar rights in such loans. Such investments may be secured or unsecured and may be newly-originated (and may be specifically designed for the Fund). Indebtedness is different from traditional debt securities in that debt securities are part of a large issue of securities to the public and indebtedness may not be a security, but may represent a specific commercial loan to a borrower. Loan participations typically represent direct participation, together with other parties, in a loan to a corporate borrower, and generally are offered by banks or other financial institutions or lending syndicates. The Fund may participate in such syndications, or can buy part of a loan, becoming a part lender. When purchasing indebtedness and loan participations, the Fund assumes the credit risk associated with the corporate borrower and may assume the credit risk associated with an interposed bank or other financial intermediary. The indebtedness and loan participations in which the Fund may invest may not be rated by any nationally recognized rating service.

A financial institution’s employment as agent bank might be terminated in the event that it fails to observe a requisite standard of care or becomes insolvent. A successor agent bank would generally be appointed to replace the terminated agent bank, and assets held by the agent bank under the loan agreement should remain available to holders of such indebtedness. However, if assets held by the agent bank for the benefit of the Fund were determined to be subject to the claims of the agent bank’s general creditors, the Fund might incur certain costs and delays in realizing payment on a loan or loan participation and could suffer a loss of principal and/or interest. In situations involving other interposed financial institutions (e.g., an insurance company or governmental agency) similar risks may arise.

Purchasers of loans and other forms of direct indebtedness depend primarily upon the creditworthiness of the corporate borrower for payment of principal and interest. If the Fund does not receive scheduled interest or principal payments on such indebtedness, the Fund’s yield could be adversely affected. Loans that are fully secured offer the Fund more protection than an unsecured loan in the event of non-payment of scheduled interest or principal. However, there is no assurance that the liquidation of collateral from a secured loan would satisfy the corporate borrower’s obligation, or that the collateral can be liquidated. In the event of the bankruptcy of a borrower, the Fund could experience delays or limitations in its ability to realize the benefits of any collateral securing a loan.

Loans and other types of direct indebtedness (which the Fund may invest in or otherwise gain exposure to) may not be readily marketable and may be subject to restrictions on resale. In some cases, negotiations involved in disposing of indebtedness may require weeks to complete. Consequently, some indebtedness may be difficult or impossible to dispose of readily at what the Investment Manager believes to be a fair price. In addition, valuation of illiquid indebtedness involves a greater degree of judgment in determining the Fund’s net asset value than if that value were based on available market quotations, and could result in significant variations in the Fund’s daily share price. At the same time, some loan interests are traded among certain financial institutions and accordingly may be deemed liquid. As the market for different types of indebtedness develops, the liquidity of these instruments is expected to improve. Investments in loan participations are considered to be debt obligations for purposes of the Fund’s investment restriction relating to the lending of funds or assets.

Investments in loans through a purchase of a loan or a direct assignment of a financial institution’s interests with respect to a loan may involve additional risks to the Fund. The purchaser of an assignment typically succeeds to all the rights and obligations under the loan agreement with the same rights and obligations as the assigning lender. Assignments may, however, be arranged through private negotiations between potential assignees and potential assignors, and the rights and obligations acquired by the purchaser of an assignment may differ from, and be more limited than, those held by the assigning lender. For example, if a loan is foreclosed, the Fund could become owner, in whole or in part, of any collateral, which could include, among other assets, real estate or other real or personal property, and would bear the costs and liabilities associated with owning and holding or disposing of the collateral (see “Real Estate Assets and Related Derivatives” above). In addition, it is conceivable that under emerging legal theories of lender liability, the Fund could be held liable as co-lender. It is unclear whether loans and other forms of direct indebtedness offer securities law protections against fraud and misrepresentation. In the absence of definitive regulatory guidance, the Fund relies on the Investment Manager’s research in an attempt to avoid situations where fraud or misrepresentation could adversely affect the Fund.

The Fund may invest in debtor-in-possession financings (commonly known as “DIP financings”). DIP financings are arranged when an entity seeks the protections of the bankruptcy court under Chapter 11 of the U.S. Bankruptcy Code. These financings allow the entity to continue its business operations while reorganizing under Chapter 11. Such financings constitute senior liens on unencumbered security (i.e., security not subject to other creditors’ claims). There is a risk that the entity will not emerge from Chapter 11 and be forced to liquidate its assets under Chapter 7 of the U.S. Bankruptcy Code. In the event of liquidation, the Fund’s only recourse will be against the property securing the DIP financing.

In determining whether to make a direct loan, the Fund will rely primarily upon the creditworthiness of the borrower and/or any collateral for payment of interest and repayment of principal. In making a direct loan, the Fund is exposed to the risk that the borrower may default or become insolvent and, consequently, that the Fund will lose money on the loan. Furthermore, direct loans may subject the Fund to liquidity and interest rate risk and certain direct loans may be deemed illiquid. Direct loans are not publicly traded and may not have a secondary market. The lack of a secondary market for direct loans may have an adverse impact on the ability of the Fund to dispose of a direct loan and/or to value the direct loan.

In purchasing loans, the Fund will compete with a broad spectrum of lenders. Increased competition for, or a diminishment in the available supply of, qualifying loans could result in lower yields on such loans, which could reduce Fund performance.

Various state licensing requirements could apply to the Fund with respect to investments in loans and similar assets. The licensing requirements could apply depending on the location of the borrower, the location of the collateral securing the loan, or the location where the Fund or PIMCO operates or has offices. In states in which it is licensed, the Fund or PIMCO will be required to comply with applicable laws and regulations, including consumer protection and anti-fraud laws, which could impose restrictions on the Fund’s or PIMCO’s ability to take certain actions to protect the value of its investments in such assets and impose compliance costs. Failure to comply with such laws and regulations could lead to, among other penalties, a loss of the Fund’s or PIMCO’s license, which in turn could require the Fund to divest assets located in or secured by real property located in that state. These risks will also apply to issuers and entities in which the Fund invests that hold similar assets, as well as any origination company or servicer in which the Fund owns an interest.

Loan origination and servicing companies are routinely involved in legal proceedings concerning matters that arise in the ordinary course of their business. These legal proceedings range from actions involving a single plaintiff to class action lawsuits with potentially tens of thousands of class members. In addition, a number of participants in the loan origination and servicing industry (including control persons of industry participants) have been the subject of regulatory actions by state regulators, including state Attorneys General, and by the federal government. Governmental investigations, examinations or regulatory actions, or private lawsuits, including purported class action lawsuits, may adversely affect such companies’ financial results. To the extent the Fund seeks to engage in origination and/or servicing directly, or has a financial interest in, or is otherwise affiliated with, an origination or servicing company, the Fund will be subject to enhanced risks of litigation, regulatory actions and other proceedings. As a result, the Fund may be required to pay legal fees, settlement costs, damages, penalties or other charges, any or all of which could materially adversely affect the Fund and its investments.

The Fund limits the amount of its total assets that it will invest in any one issuer or in issuers within the same industry (see “Investment Restrictions”). For purposes of these limits, the Fund generally will treat the corporate borrower as the “issuer” of indebtedness held by the Fund. In the case of loan participations where a bank or other lending institution serves as a financial intermediary between the Fund and the corporate borrower, if the participation does not shift to the Fund the direct debtor-creditor relationship with the corporate borrower, the Fund will treat both the lending bank or other lending institution and the corporate borrower as “issuers.” Treating a financial intermediary as an issuer of indebtedness may restrict the Fund’s ability to invest in indebtedness related to a single financial intermediary, or a group of intermediaries engaged in the same industry, even if the underlying borrowers represent many different companies and industries.

To the extent the Fund invests in senior loans, the Fund may be subject to greater levels of credit risk, call risk, settlement risk and liquidity risk, than funds that do not invest in such securities. These instruments are considered predominantly speculative with respect to an issuer’s continuing ability to make principal and interest payments, and may be more volatile than other types of securities. An economic downturn or individual corporate developments could adversely affect the market for these instruments and reduce the Fund’s ability to sell these instruments at an advantageous time or price. An economic downturn would generally lead to a higher non-payment rate and, a senior loan may lose significant market value before a default occurs. The Fund may also be subject to greater levels of liquidity risk than funds that do not invest in senior loans. In addition, the senior loans in which the Fund invests may not be listed on any exchange and a secondary market for such loans may be comparatively illiquid relative to markets for other more liquid fixed income securities. Consequently, transactions in senior loans may involve greater costs than transactions in more actively traded securities. Restrictions on transfers in loan agreements, a lack of publicly-available information, irregular trading activity and wide bid/ask spreads among other factors, may, in certain circumstances, make senior loans difficult to sell at an advantageous time or price than other types of securities or instruments. These factors may result in the Fund being unable to realize full value for the senior loans and/or may result in the Fund not receiving the proceeds from a sale of a senior loan for an extended period after such sale, each of which could result in losses to the Fund. Senior loans may have extended trade settlement periods which may result in cash not being immediately available to the Fund. If an issuer of a senior loan prepays or redeems the loan prior to maturity, the Fund will have to reinvest the proceeds in other senior loans or similar instruments that may pay lower interest rates. Because of the risks involved in investing in senior loans, an investment in the Fund that invests in such instruments should be considered speculative.

The Fund may also enter into, or acquire participations in, delayed funding loans and revolving credit facilities. Delayed funding loans and revolving credit facilities are borrowing arrangements in which the lender agrees to make loans up to a maximum amount upon demand by the borrower during a specified term. A revolving credit facility differs from a delayed funding loan in that as the borrower repays the loan, an amount equal to the repayment may be borrowed again during the term of the revolving credit facility. Delayed funding loans and revolving credit facilities usually provide for floating or variable rates of interest. These commitments may have the effect of requiring the Fund to increase its investment in a company at a time when it might not otherwise decide to do so (including a time when the company’s financial condition makes it unlikely that such amounts will be repaid).

To the extent that the Fund is committed to advance additional funds, it will at all times segregate assets, determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees, in an amount sufficient to meet such commitments.

The Fund may invest in delayed funding loans and revolving credit facilities with credit quality comparable to that of issuers of its securities investments. Delayed funding loans and revolving credit facilities may be subject to restrictions on transfer, and only limited opportunities may exist to resell such instruments. As a result, the Fund may be unable to sell such investments at an opportune time or may have to resell them at less than fair market value. For a further discussion of the risks involved in investing in loan participations and other forms of direct indebtedness see “Loans and Other Indebtedness, Loan Participations and Assignments.” Participation interests in revolving credit facilities will be subject to the limitations discussed in “Loans and Other Indebtedness, Loan Participations and Assignments.” Delayed funding loans and revolving credit facilities are considered to be debt obligations for purposes of the Fund’s investment restriction relating to the lending of funds or assets by the Fund.

The Fund may invest directly or indirectly in zero-coupon securities, “step-ups” and PIKs. Zero-coupon securities are debt obligations that do not entitle the holder to any periodic payments of interest either for the entire life of the obligation or for an initial period after the issuance of the obligations. Like zero-coupon bonds, “step-up” bonds pay no interest initially but eventually begin to pay a coupon rate prior to maturity, which rate may increase at stated intervals during the life of the security. PIKs are debt obligations that pay “interest” in the form of other debt obligations instead of cash. Each of these instruments is normally issued and traded at a deep discount from face value. The amount of the discount varies depending on such factors as the time remaining until maturity of the securities, prevailing interest rates, the liquidity of the security and the perceived credit quality of the issuer. The market prices of zero-coupon bonds, step-ups and PIKs generally are more volatile than the market prices of debt instruments that pay interest currently and in cash and are likely to respond to changes in interest rates to a greater degree than do other types of securities having similar maturities and credit quality.

In order to satisfy a requirement for qualification as a “regulated investment company” under the Code, an investment company, such as the Fund, must distribute each year at least 90% of its net investment income, including the original issue discount accrued on zero-coupon bonds, step-ups and PIKs. Because the Fund will not, on a current basis, receive cash payments from the issuer of these securities in respect of any accrued original issue discount, in some years, the Fund may have to sell other portfolio holdings in order to obtain cash to satisfy the distribution requirements under the Code even though investment considerations might otherwise make it undesirable for the Fund to sell securities at such time. Under many market conditions, investments in zero-coupon bonds, step-ups and PIKs may be illiquid, making it difficult for the Fund to dispose of them or determine their current value.

The Fund may invest in floating rate debt instruments, including Senior Loans (described in more detail above). Variable and floating rate securities are securities that pay interest at rates that adjust whenever a specified interest rate changes, float at a fixed margin above a generally recognized base lending rate and/or reset or are redetermined (e.g., pursuant to an auction) on specified dates (such as the last day of a month or calendar quarter). These instruments may include, without limitation, variable-rate preferred stock, bank loans, money market instruments and certain types of mortgage-backed and other asset-backed securities. Due to their variable- or floating-rate features, these instruments will generally pay higher levels of income in a rising interest rate environment and lower levels of income as interest rates decline. For the same reason, the market value of a variable- or floating-rate instrument is generally expected to have less sensitivity to fluctuations in market interest rates than a fixed-rate instrument, although the value of a floating-rate instrument may nonetheless decline as interest rates rise and due to other factors, such as changes in credit quality.

The Fund may invest in floating rate debt instruments (“floaters”) and engage in credit spread trades. The interest rate on a floater is a variable rate which is tied to another interest rate, such as a money-market index or U.S. Treasury bill rate. The interest rate on a floater resets periodically, typically every six months. While, because of the interest rate reset feature, floaters provide the Fund with a certain degree of protection against rises in interest rates, the Fund will participate in any declines in interest rates as well. A credit spread trade is an investment position relating to a difference in the prices or interest rates of two securities or currencies where the value of the investment position is determined by movements in the difference between the prices or interest rates, as the case may be, of the respective securities or currencies. The Fund may also invest without limit in inverse floating rate debt instruments (“inverse floaters”). The interest rate on an inverse floater resets in the opposite direction from the market rate of interest to which the inverse floater is indexed. An inverse floater may exhibit greater price volatility than a fixed rate obligation of similar credit quality. See “Mortgage-Related and Other Asset-Backed Securities” above. The Fund’s investments in variable- and floating-rate securities may require the Fund to accrue and distribute income not yet received. As a result, in order to generate cash to make the requisite distributions, the Fund may be required to sell securities in its portfolio that it would otherwise have continued to hold. See “Taxation.”

The Fund may invest in inflation-indexed bonds. Inflation-indexed bonds are fixed income securities whose principal value is periodically adjusted according to the rate of inflation. Two structures are common. The U.S. Treasury and some other issuers utilize a structure that accrues inflation into the principal value of the bond. Many other issuers pay out the Consumer Price Index accruals as part of a semiannual coupon.

Inflation-indexed bonds issued by the U.S. Treasury have maturities of approximately five, ten or thirty years, although it is possible that securities with other maturities will be issued in the future. The U.S. Treasury securities pay interest on a semi-annual basis equal to a fixed percentage of the inflation-adjusted principal amount. For example, if the Fund purchased an inflation-indexed bond with a par value of $1,000 and a 3% real rate of return coupon (payable 1.5% semi-annually), and the rate of inflation over the first six months was 1%, the mid-year par value of the bond would be $1,010 and the first semi-annual interest payment would be $15.15 ($1,010 times 1.5%). If inflation during the second half of the year resulted in the whole year’s inflation equaling 3%, the end-of-year par value of the bond would be $1,030 and the second semi-annual interest payment would be $15.45 ($1,030 times 1.5%).

If the periodic adjustment rate measuring inflation falls, the principal value of inflation-indexed bonds will be adjusted downward, and consequently the interest payable on these securities (calculated with respect to a smaller principal amount) will be reduced. Repayment of the original bond principal upon maturity (as adjusted for inflation) is guaranteed in the case of a U.S. Treasury inflation-indexed bond, even during a period of deflation, although the inflation-adjusted principal received could be less than the inflation-adjusted principal that had accrued to the bond at the time of purchase. However, the current market value of the bonds is not guaranteed and will fluctuate. The Fund may also invest in other inflation-related bonds that may or may not provide a similar guarantee. If a guarantee of principal is not provided, the adjusted principal value of the bond repaid at maturity may be less than the original principal amount.

The value of inflation-indexed bonds is expected to change in response to changes in real interest rates. Real interest rates in turn are tied to the relationship between nominal interest rates and the rate of inflation. Therefore, if the rate of inflation rises at a faster rate than nominal interest rates, real interest rates might decline, leading to an increase in value of inflation-indexed bonds. In contrast, if nominal interest rates increase at a faster rate than inflation, real interest rates might rise, leading to a decrease in value of inflation-indexed bonds.

While these securities are expected to provide protection from long-term inflationary trends, short-term increases in inflation may lead to a decline in value. If interest rates rise due to reasons other than inflation (for example, due to changes in currency exchange rates), investors in these securities may not be protected to the extent that the increase is not reflected in the bond’s inflation measure.

The periodic adjustment of U.S. inflation-indexed bonds is tied to the Consumer Price Index for All Urban Consumers (“CPI-U”), which is not seasonably adjusted and which is calculated monthly by the U.S. Bureau of Labor Statistics. The CPI-U is a measurement of changes in the cost of living, made up of components such as housing, food, transportation and energy. Inflation-indexed bonds issued by a foreign (non-U.S.) government are generally adjusted to reflect a comparable inflation index calculated by that government. There can be no assurance that the CPI-U or any foreign (non-U.S.) inflation index will accurately measure the real rate of inflation in the prices of goods and services. Moreover, there can be no assurance that the rate of inflation in a foreign (non-U.S.) country will be correlated to the rate of inflation in the United States.

Any increase in the principal amount of an inflation-indexed bond will be considered taxable ordinary income, even though investors do not receive their principal until maturity. As a result, in order to generate cash to make the requisite distributions, the Fund may be required to sell securities in its portfolio that it would otherwise have continued to hold. See “Taxation.”

The Fund may obtain event-linked exposure by investing in “event-linked bonds,” or “event-linked swaps,” or by implementing “event-linked strategies.” Event-linked exposure results in gains that typically are contingent on the non-occurrence of a specific “trigger” event, such as a hurricane, earthquake or other physical or weather-related phenomena. Some event-linked bonds are commonly referred to as “catastrophe bonds.” They may be issued by government agencies,

insurance companies, reinsurers, special purpose corporations or other on-shore or off-shore entities (such special purpose entities are created to accomplish a narrow and well-defined objective, such as the issuance of a note in connection with a reinsurance transaction). If a trigger event causes losses exceeding a specific amount in the geographic region and time period specified in a bond, the Fund may lose a portion or all of its principal invested in the bond. If no trigger event occurs, the Fund will recover its principal plus interest. For some event-linked bonds, the trigger event or losses may be based on company-wide losses, index-portfolio losses, industry indices or readings of scientific instruments rather than specified actual losses. Often the event-linked bonds provide for extensions of maturity that are mandatory, or optional at the discretion of the issuer, in order to process and audit loss claims in those cases where a trigger event has, or possibly has, occurred. An extension of maturity may increase volatility. In addition to the specified trigger events, event-linked bonds also may expose the Fund to certain unanticipated risks including but not limited to issuer risk, credit risk, counterparty risk, adverse regulatory or jurisdictional interpretations and adverse tax consequences.

Event-linked bonds are a relatively new type of financial instrument. As such, there is no significant trading history for many of these securities, and there can be no assurance that a liquid market in these instruments will develop. Lack of a liquid market may impose the risk of higher transaction costs and the possibility that the Fund may be forced to liquidate positions when it would not be advantageous to do so. Event-linked bonds are typically rated, and the Fund will only invest in event-linked bonds that meet the credit quality requirements for the Fund.

The Fund may, but is not required to, utilize various derivative strategies (both long and short positions) involving the purchase or sale of futures and forward contracts (including foreign currency exchange contracts), call and put options, credit default swaps, total return swaps, basis swaps and other swap agreements and other derivative instruments for investment purposes, leveraging purposes or in an attempt to hedge against market, credit, interest rate, currency and other risks in the portfolio. The Fund’s use of credit default swaps and certain other derivative instruments will be limited by the Fund’s 20% limit on illiquid investments to the extent they are determined to be illiquid.

Generally, derivatives are financial contracts whose value depends on, or is derived from, the value of an underlying asset, reference rate or index and may relate to, among other things, stocks, bonds, interest rates, currencies or currency exchange rates, commodities, related indexes and other assets. The following describes certain derivative instruments and products in which the Fund may invest and risks associated therewith. The derivatives market is always changing and the Fund may invest in derivatives other than those shown below.

In pursuing its investment objective, the Fund may purchase and sell (write) both put options and call options on securities, swap agreements, securities indexes, commodity indexes and foreign currencies, and enter into interest rate, foreign currency, index and commodity futures contracts and purchase and sell options on such futures contracts (“futures options”) for hedging purposes or as part of their overall investment strategies. The Fund also may purchase and sell foreign currency options for purposes of increasing exposure to a foreign currency or to shift exposure to foreign currency fluctuations from one country to another. The Fund also may enter into swap agreements with respect to interest rates, commodities, indexes of securities or commodities, and to the extent it may invest in foreign currency denominated securities, may enter into swap agreements with

respect to foreign currencies. The Fund may invest in structured notes. If other types of financial instruments, including other types of options, futures contracts, or futures options are traded in the future, the Fund may also use those instruments, provided that their use is consistent with the Fund’s investment objective.

The value of some derivative instruments in which the Fund invest may be particularly sensitive to changes in prevailing interest rates, and, like the other investments of the Fund, the ability of the Fund to successfully utilize these instruments may depend in part upon the ability of PIMCO to forecast interest rates and other economic factors correctly. If PIMCO incorrectly forecasts such factors and has taken positions in derivative instruments contrary to prevailing market trends, the Fund could be exposed to additional, unforeseen risks, including the risk of loss.

The Fund might not employ any of the strategies described below, and no assurance can be given that any strategy used will succeed. If PIMCO incorrectly forecasts interest rates, market values or other economic factors in using a derivatives strategy for the Fund, the Fund might have been in a better position if it had not entered into the transaction at all. The use of these strategies involves certain special risks, including a possible imperfect correlation, or even no correlation, between price movements of derivative instruments and price movements of related investments. While some strategies involving derivative instruments can reduce the risk of loss, they can also reduce the opportunity for gain or even result in losses by offsetting favorable price movements in related investments or otherwise, due to the possible inability of the Fund to purchase or sell a portfolio security at a time that otherwise would be favorable or the possible need to sell a portfolio security at a disadvantageous time because the Fund is required to maintain asset coverage or offsetting positions in connection with transactions in derivative instruments, and the possible inability of the Fund to close out or to liquidate its derivatives positions. In addition, the Fund’s use of such instruments may cause the Fund to realize higher amounts of short-term capital gains (generally subject to tax when distributed to shareholders at ordinary income tax rates) than if it had not used such instruments. If the Fund gains exposure to an asset class using derivative instruments backed by a collateral portfolio of fixed income instruments, changes in the value of the fixed income instruments may result in greater or lesser exposure to that asset class than would have resulted from a direct investment in securities comprising that asset class.

Participation in the markets for derivative instruments involves investment risks and transaction costs to which the Fund may not be subject absent the use of these strategies. The skills needed to successfully execute derivative strategies may be different from those needed for other types of transactions. If the Fund incorrectly forecasts the value and/or creditworthiness of securities, currencies, interest rates, counterparties or other economic factors involved in a derivative transaction, the Fund might have been in a better position if the Fund had not entered into such derivative transaction. In evaluating the risks and contractual obligations associated with particular derivative instruments, it is important to consider that certain derivative transactions may be modified or terminated only by mutual consent of the Fund and its counterparty and certain derivative transactions may be terminated by the counterparty or the Fund, as the case may be, upon the occurrence of certain Fund-related or counterparty-related events, which may result in losses or gains to the Fund based on the market value of the derivative transactions entered into between the Fund and the counterparty. In addition, such early terminations may result in taxable events and accelerate gain or loss recognition for tax purposes. It may not be possible for the Fund to modify, terminate, or offset the Fund’s obligations or the Fund’s exposure to the risks associated with a derivative transaction prior to its termination or maturity date, which may create a possibility of increased volatility and/or decreased liquidity to the Fund. Upon the expiration or termination of a

particular contract, the Fund may wish to retain the Fund’s position in the derivative instrument by entering into a similar contract, but may be unable to do so if the counterparty to the original contract is unwilling to enter into the new contract and no other appropriate counterparty can be found, which could cause the Fund not to be able to maintain certain desired investment exposures or not to be able to hedge other investment positions or risks, which could cause losses to the Fund. Furthermore, after such an expiration or termination of a particular contract, the Fund may have fewer counterparties with which to engage in additional derivative transactions, which could lead to potentially greater counterparty risk exposure to one or more counterparties and which could increase the cost of entering into certain derivatives. In such cases, the Fund may lose money.

The Fund may engage in investment strategies, including the use of derivatives, to, among other things, seek to generate current, distributable income without regard to possible declines in the Fund’s net asset value. The Fund’s income and gain-generating strategies, including certain derivatives strategies, may generate current, distributable income, even if such strategies could potentially result in declines in the Fund’s net asset value. The Fund’s income and gain-generating strategies, including certain derivatives strategies, may generate current taxable income and gains sufficient to support monthly distributions even in situations when the 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 the Fund’s debt investments, or arising from its use of derivatives. Consequently, shareholders may receive distributions subject to tax at ordinary income rates at a time when their investment in the Fund has declined in value, which may be economically similar to a taxable return of capital.

Also, suitable derivative and/or hedging transactions may not be available in all circumstances, and there can be no assurance that the Fund will be able to identify or employ a desirable derivative and/or hedging transaction at any time or from time to time or, if a strategy is used, that it will be successful.

As further described below under “Additional Risk Factors in Cleared Derivatives Transactions,” federal legislation has been recently enacted in the U.S. that provides for new clearing, margin, reporting and registration requirements for participants in the derivatives market. While the ultimate impact is not yet clear, these changes could restrict and/or impose significant costs or other burdens upon the Fund’s ability to participate in derivatives transactions. Similarly, these changes could impose limits or restrictions on the counterparties with which the Fund engages in derivatives transactions. As a result, the Fund may be unable to use certain derivative instruments or otherwise execute its investment strategy. These risks may be particularly acute to the extent the Fund use commodity-related derivative instruments.

Options on Securities and Indexes. The Fund may, to the extent specified herein or in the Prospectus, purchase and sell both put and call options on equity, fixed income or other securities or indexes in standardized contracts traded on foreign or domestic securities exchanges, boards of trade, or similar entities, or quoted on the National Association of Securities Dealers Automated Quotations (“NASDAQ”) System or on a regulated foreign OTC market, and agreements, sometimes called cash puts, which may accompany the purchase of a new issue of bonds from a dealer. Among other reasons, the Fund may purchase put options to protect holdings in an underlying or related security against a decline in market value, and may purchase call options to protect against increases in the prices of securities it intends to purchase pending its ability to invest in such securities in an orderly manner.

An option on a security (or index) is a contract that gives the holder of the option, in return for a premium, the right to buy from (in the case of a call) or sell to (in the case of a put) the writer of the option the security underlying the option (or the cash value of the index) at a specified exercise price, often at any time during the term of the option for American options or only at expiration for European options. The writer of an option on a security has the obligation upon exercise of the option to deliver the underlying security upon payment of the exercise price (in the case of a call) or to pay the exercise price upon delivery of the underlying security (in the case of a put). Certain put options written by the Fund, which counterparties may use as a source of liquidity, may be structured to have an exercise price that is less than the market value of the underlying securities that would be received by the Fund. Upon exercise, the writer of an option on an index is obligated to pay the difference between the cash value of the index and the exercise price multiplied by the specified multiplier for the index option. An index is designed to reflect features of a particular financial or securities market, a specific group of financial instruments or securities, or certain economic indicators.

The Fund will “cover” its obligations when it writes call options or put options. In the case of a call option on a debt obligation or other security, the option is “covered” if the Fund owns the security underlying the call or has an absolute and immediate right to acquire that security without additional cash consideration (or, if additional cash consideration is required, cash or other assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees in such amount are segregated by its custodian or “earmarked”) upon conversion or exchange of other securities held by the Fund. A call option on a security is also “covered” if the Fund does not hold the underlying security or have the right to acquire it, but the Fund segregates or “earmarks” assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees in an amount equal to the value of the underlying security (minus any collateral deposited with a broker-dealer or other financial institution), on a mark-to-market basis (a so-called “naked” call option).

For a call option on an index, the option is covered if the Fund maintains with its custodian assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees in an amount equal to the value of the underlying index. A call option is also covered if the Fund holds a call on the same security or index as the call written where the exercise price of the call held is (i) equal to or less than the exercise price of the call written, or (ii) greater than the exercise price of the call written, provided the difference is maintained by the Fund in segregated or “earmarked” assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees. A put option on a security or an index is “covered” if the Fund segregates or “earmarks” assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees equal to the exercise price. A put option is also covered if the Fund holds a put on the same security or index as the put written where the exercise price of the put held is (i) equal to or greater than the exercise price of the put written, or (ii) less than the exercise price of the put written, provided the difference is maintained by the Fund in segregated or “earmarked” assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees. Obligations under written call and put options so covered will not be construed to be “senior securities” for purposes of the Fund’s investment restrictions concerning senior securities and borrowings.

If an option written by the Fund expires unexercised, the Fund realizes a capital gain equal to the premium received at the time the option was written. If an option purchased by the Fund expires unexercised, the Fund realizes a capital loss equal to the premium paid. Prior to the earlier of

exercise or expiration, an exchange-traded option may be closed out by an offsetting purchase or sale of an option of the same series (type, exchange, underlying security or index, exercise price, and expiration). There can be no assurance, however, that a closing purchase or sale transaction can be effected when the Fund desires. In addition, the Fund may sell put or call options it has previously purchased, which could result in a net gain or loss depending on whether the amount realized on the sale is more or less than the premium and other transaction costs paid on the put or call option which is sold. Prior to the exercise or expiration, an option may be closed out by an offsetting purchase or sale of an option of the same series.

The Fund will realize a capital gain from a closing purchase transaction if the cost of the closing option is less than the premium received from writing the option, or, if it is more, the Fund will realize a capital loss. If the premium received from a closing sale transaction is more than the premium paid to purchase the option, the Fund will realize a capital gain or, if it is less, the Fund will realize a capital loss. The principal factors affecting the market value of a put or a call option include supply and demand, interest rates, the current market price of the underlying security or index in relation to the exercise price of the option, the volatility of the underlying security or index, and the time remaining until the expiration date.

The premium paid for a put or call option purchased by the Fund is an asset of the Fund. The premium received for an option written by the Fund is recorded as a deferred credit. The value of an option purchased or written is marked to market daily and is valued in accordance with the Fund’s valuation policies and procedures. See “Net Asset Value” below.

The Fund may write covered straddles consisting of a combination of a call and a put written on the same underlying security. A straddle will be covered when sufficient liquid assets are deposited to meet the Fund’s immediate obligations. The Fund may use the same liquid assets to cover both the call and put options where the exercise price of the call and put are the same, or the exercise price of the call is higher than that of the put. In such cases, the Fund will also segregate or “earmark” liquid assets equivalent to the amount, if any, by which the put is “in the money.”

OTC Options. The staff of the SEC has taken the position that purchased OTC options and the assets used as cover for written OTC options should generally be treated as illiquid. However, the staff of the SEC has also taken the position that the determination of whether a particular instrument is liquid should be made under guidelines and standards established by a fund’s board of trustees. The SEC staff has provided examples of factors that may be taken into account in determining whether a particular instrument should be treated as liquid. Pursuant to policies adopted by the Fund’s Board of Trustees, purchased OTC options and the assets used as cover for OTC options written by the Fund may be treated as liquid under certain circumstances, such as when PIMCO has the contractual right to terminate or close out the OTC option on behalf of the Fund within seven days. These policies are not fundamental policies of the Fund and may be changed or modified by the Board of Trustees without the approval of shareholders, provided that any such change or modification will be consistent with applicable positions of the SEC staff.

Risks Associated with Options on Securities and Indexes. There are several risks associated with transactions in options on securities and on indexes. For example, there are significant differences between the securities and options markets that could result in an imperfect correlation between these markets, causing a given transaction not to achieve its objectives. A decision as to whether, when and how to use options involves the exercise of skill and judgment, and even a well-conceived transaction may be unsuccessful to some degree because of market behavior or unexpected events.

During the option period, the covered call writer has, in return for the premium on the option, given up the opportunity to profit from a price increase in the underlying security above the exercise price, but, as long as its obligation as a writer continues, has retained the risk of loss should the price of the underlying security decline. The writer of an option often has no control over the time when it may be required to fulfill its obligation as a writer of the option. Once an option writer has received an exercise notice, it cannot effect a closing purchase transaction in order to terminate its obligation under the option and must deliver the underlying security at the exercise price. To the extent the Fund writes a put option, the Fund has assumed the obligation during the option period to purchase the underlying investment from the put buyer at the option’s exercise price if the put buyer exercises its option, regardless of whether the value of the underlying investment falls below the exercise price. This means that the Fund that writes a put option may be required to take delivery of the underlying investment and make payment for such investment at the exercise price. This may result in losses to the Fund and may result in the Fund holding the underlying investment for some period of time when it is disadvantageous to do so. If a put or call option purchased by the Fund is not sold when it has remaining value, and if the market price of the underlying security remains equal to or greater than the exercise price (in the case of a put), or remains less than or equal to the exercise price (in the case of a call), the Fund will lose its entire investment in the option. Also, where a put or call option on a particular security is purchased to hedge against price movements in a related security, the price of the put or call option may move more or less than the price of the related security.

There can be no assurance that a liquid market will exist when the Fund seeks to close out an option position. If the Fund were unable to close out an option that it had purchased on a security, it would have to exercise the option in order to realize any profit or the option may expire worthless. If the Fund were unable to close out a covered call option that it had written on a security, it would not be able to sell the underlying security unless the option expired without exercise. As the writer of a covered call option, the Fund forgoes, during the option’s life, the opportunity to profit from increases in the market value of the security covering the call option above the sum of the premium and the exercise price of the call.

If trading were suspended in an option purchased by the Fund, the Fund would not be able to close out the option. If restrictions on exercise were imposed, the Fund might be unable to exercise an option it has purchased. Except to the extent that a call option on an index written by the Fund is covered by an option on the same index purchased by the Fund, movements in the index may result in a loss to the Fund; however, such losses may be mitigated by changes in the value of the Fund’s securities during the period the option was outstanding.

To the extent that the Fund writes a call option on a security it holds in its portfolio and intends to use such security as the sole means of “covering” its obligation under the call option, the Fund has, in return for the premium on the option, given up the opportunity to profit from a price increase in the underlying security above the exercise price during the option period, but, as long as its obligation under such call option continues, has retained the risk of loss should the price of the underlying security decline. If the Fund were unable to close out such a call option, the Fund would not be able to sell the underlying security unless the option expired without exercise.

Foreign Currency Options. To the extent the Fund invests in foreign currency-denominated securities, it may buy or sell put and call options on foreign currencies as a hedge against changes in the value of the U.S. dollar (or another currency) in relation to a foreign currency in which the Fund’s securities may be denominated. In addition, each of the Fund may buy or sell put and call options on foreign currencies either on exchanges or in the OTC market. A put option on a foreign currency gives the purchaser of the option the right to sell a foreign currency at the exercise price until the option expires. A call option on a foreign currency gives the purchaser of the option the right to purchase the currency at the exercise price until the option expires. Currency options traded on U.S. or other exchanges may be subject to position limits which may limit the ability of the Fund to reduce foreign currency risk using such options. OTC options differ from traded options in that they are bilateral contracts with price and other terms negotiated between buyer and seller, and generally do not have as much market liquidity as exchange-traded options. Under definitions adopted by the CFTC and SEC, many foreign currency options are considered swaps for certain purposes, including determination of whether such instruments need to be exchange-traded and centrally cleared as discussed further in “Risks of Potential Government Regulation of Derivatives.”

Futures Contracts and Options on Futures Contracts. A futures contract is an agreement to buy or sell a security or other asset for a set price on a future date. These contracts are traded on exchanges, so that, in most cases, a party can close out its position on the exchange for cash, without delivering the underlying security or other underlying asset. An option on a futures contract gives the holder of the option the right to buy or sell a position in a futures contract from or to the writer of the option, at a specified price and on or before a specified expiration date. The Fund may invest in futures or options on futures with respect to interest rates, foreign currencies, securities or commodity indexes. The Fund may invest in foreign exchange futures contracts and options thereon (“futures options”) that are traded on a U.S. or foreign exchange or board of trade, or similar entity, or quoted on an automated quotation system as an adjunct to their securities activities. In addition, the Fund may purchase and sell futures contracts on various securities indexes (“Index Futures”) and related options for hedging purposes and for investment purposes. The Fund purchase and sale of Index Futures is limited to contracts and exchanges which have been approved by the CFTC. Through the use of Index Futures and related options, the Fund may diversify risk in its portfolio without incurring the substantial brokerage costs which may be associated with investment in the securities of multiple issuers. The Fund may also avoid potential market and liquidity problems which may result from increases in positions already held by the Fund.

An interest rate, commodity, foreign currency or index futures contract provides for the future sale or purchase of a specified quantity of a financial instrument, commodity, foreign currency or the cash value of an index at a specified price and time. An Index Future is an agreement pursuant to which a party agrees to take or make delivery of an amount of cash equal to the difference between the value of a securities index (“Index”) at the close of the last trading day of the contract and the price at which the index contract was originally written. Although the value of an Index might be a function of the value of certain specified securities, no physical delivery of these securities is made. A unit is the value of the relevant Index from time to time. Entering into a contract to buy units is commonly referred to as buying or purchasing a contract or holding a long position in an Index. Index Futures contracts can be traded through all major commodity brokers. The Fund will ordinarily be able to close open positions on the futures exchange on which Index Futures are then traded at any time up to and including the expiration day. As described below, the Fund will be required to segregate initial margin in the name of the futures broker upon entering into an Index Future. Variation margin will be paid to and received from the broker on a daily basis as the contracts are marked to market. For example, when the Fund has purchased an Index Future and the

price of the relevant Index has risen, that position will have increased in value and the Fund will receive from the broker a variation margin payment equal to that increase in value. Conversely, when the Fund has purchased an Index Future and the price of the relevant Index has declined, the position would be less valuable and the Fund would be required to make a variation margin payment to the broker.

The Fund may close open positions on the futures exchanges on which Index Futures are traded at any time up to and including the expiration day. All positions which remain open at the close of the last business day of the contract’s life are required to settle on the next business day (based upon the value of the relevant index on the expiration day), with settlement made with the appropriate clearing house. Positions in Index Futures may be closed out by the Fund only on the futures exchanges upon which the Index Futures are then traded.

A public market exists in futures contracts covering a number of indexes as well as financial instruments and foreign currencies, including, but not limited to: the S&P 500; the S&P Midcap 400; the Nikkei 225; the Markit CDX credit index; the iTraxx credit index; U.S. Treasury bonds; U.S. Treasury notes; U.S. Treasury bills; 90-day commercial paper; bank certificates of deposit; Eurodollar certificates of deposit; the Australian dollar; the Canadian dollar; the British pound; the Japanese yen; the Swiss franc; the Mexican peso; and certain multinational currencies, such as the euro. It is expected that other futures contracts will be developed and traded in the future. Certain futures contracts on indexes, financial instruments or foreign currencies may represent new investment products that lack track records.

The Fund might use financial futures contracts to hedge against anticipated changes in interest rates that might adversely affect either the value of the Fund’s securities or the price of the securities which the Fund intends to purchase. The Fund’s hedging activities may include sales of futures contracts as an offset against the effect of expected increases in interest rates, and purchases of futures contracts as an offset against the effect of expected declines in interest rates. Although other techniques could be used to reduce the Fund’s exposure to interest rate fluctuations, the Fund may be able to hedge its exposure more effectively and perhaps at a lower cost by using futures contracts and futures options. The Fund may also invest in commodity futures contracts and options thereon. A commodity futures contract is an agreement to buy or sell a commodity, such as an energy, agricultural or metal commodity at a later date at a price and quantity agreed-upon when the contract is bought or sold.

The Fund may purchase and write call and put futures options. Futures options possess many of the same characteristics as options on securities and indexes (discussed above). A futures option gives the holder the right, in return for the premium paid, to assume a long position (call) or short position (put) in a futures contract at a specified exercise price at any time during the period of the option. Upon exercise of a call option, the holder acquires a long position in the futures contract and the writer is assigned the opposite short position. In the case of a put option, the opposite is true. A call option is “in the money” if the value of the futures contract that is the subject of the option exceeds the exercise price. A put option is “in the money” if the exercise price exceeds the value of the futures contract that is the subject of the option. When a purchase or sale of a futures contract is made by the Fund, the Fund is required to segregate a specified amount of assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees (“initial margin”). The margin required for a futures contract is set by the exchange on which the contract is traded and may be modified during the term of the contract. Margin requirements on foreign exchanges may be different than U.S. exchanges. The initial margin is in the nature of a

performance bond or good faith deposit on the futures contract which is returned to the Fund upon termination of the contract, assuming all contractual obligations have been satisfied. The Fund expects to earn interest income on its initial margin deposits. A futures contract held by the Fund is valued daily at the official settlement price of the exchange on which it is traded. Each day the Fund pays or receives cash, called “variation margin,” equal to the daily change in value of the futures contract. This process is known as “marking to market.” Variation margin does not represent a borrowing or loan by the Fund but is instead a settlement between the Fund and the broker of the amount one would owe the other if the futures contract expired. In computing daily net asset value, the Fund will mark to market its open futures positions.

The Fund is also required to deposit and maintain margin with respect to put and call options on futures contracts written by it. Such margin deposits will vary depending on the nature of the underlying futures contract (and the related initial margin requirements), the current market value of the option, and other futures positions held by the Fund.

Although some futures contracts call for making or taking delivery of the underlying securities or commodities, generally these obligations are closed out prior to delivery by offsetting purchases or sales of matching futures contracts (i.e., with the same exchange, underlying security or index, and delivery month). Closing out a futures contract sale is effected by purchasing an offsetting futures contract for the same aggregate amount of the specific type of financial instrument or commodity with the same delivery date. If an offsetting purchase price is less than the original sale price, the Fund realizes a capital gain, or if it is more, the Fund realizes a capital loss.

Conversely, if an offsetting sale price is more than the original purchase price, the Fund realizes a capital gain, or if it is less, the Fund realizes a capital loss. Any transaction costs must also be included in these calculations.

The Fund may write covered straddles consisting of a call and a put written on the same underlying futures contract. A straddle will be covered when sufficient assets are deposited to meet the Fund’s immediate obligations. The Fund may use the same liquid assets to cover both the call and put options where the exercise price of the call and put are the same, or the exercise price of the call is higher than that of the put. In such cases, the Fund will also segregate liquid assets equivalent to the amount, if any, by which the put is “in the money.”

Limitations on Use of Futures and Futures Options. When purchasing a futures contract, the Fund may but is not required to “earmark” or maintain with its custodian (and mark-to-market on a daily basis) assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees that, when added to the amounts deposited with a futures commission merchant as margin, are equal to the market value of the futures contract. Alternatively, the Fund may “cover” its position by purchasing a put option on the same futures contract with a strike price as high or higher than the price of the contract held by the Fund.

When selling a futures contract, the Fund may but is not required to maintain with its custodian (and mark-to-market on a daily basis) assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees that are equal to the market value of the instruments underlying the contract. Alternatively, the Fund may “cover” its position by owning the instruments underlying the contract (or, in the case of an Index Future, a portfolio with a volatility substantially similar to that of the Index on which the futures contract is based), or by holding a call option permitting the Fund to purchase the same futures contract at a price no higher than the price of the contract written by the Fund (or at a higher price if the difference is maintained in liquid assets with the Fund’s custodian).

When selling a call option on a futures contract, the Fund may but is not required to “earmark” or maintain with its custodian (and mark-to-market on a daily basis) assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees that, when added to the amounts deposited with a futures commission merchant as margin, equal the total market value of the futures contract underlying the call option. Alternatively, the Fund may cover its position by entering into a long position in the same futures contract at a price no higher than the strike price of the call option, by owning the instruments underlying the futures contract, or by holding a separate call option permitting the Fund to purchase the same futures contract at a price not higher than the strike price of the call option sold by the Fund.

When selling a put option on a futures contract, the Fund may but is not required to “earmark” or maintain with its custodian (and mark-to-market on a daily basis) assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees that equal the purchase price of the futures contract, less any margin on deposit. Alternatively, the Fund may cover the position either by entering into a short position in the same futures contract, or by owning a separate put option permitting it to sell the same futures contract so long as the strike price of the purchased put option is the same or higher than the strike price of the put option sold by the Fund.

With respect to futures contracts that “physically settle,” the Fund may cover the open position by setting aside or “earmarking” liquid assets in an amount equal to the full notional value of the futures contract. With respect to futures that are required to “cash settle,” however, the Fund is permitted to set aside or “earmark” liquid assets in an amount equal to the Fund’s daily mark-to-market (net) obligation, if any, (in other words, the Fund’s daily net liability, if any) rather than the full notional value of the futures contract. By setting aside or “earmarking” assets equal to only its net obligation under cash-settled futures, the Fund will have the ability to utilize these contracts to a greater extent than if the Fund were required to segregate or “earmark” assets equal to the full notional value of the futures contract.

To the extent that securities with maturities greater than one year are used to segregate liquid assets to cover the Fund’s obligations under futures contracts and related options, such use will not eliminate the leverage risk arising from such use, which may tend to exaggerate the effect on net asset value of any increase or decrease in the market value of the Fund’s portfolio, and may require liquidation of portfolio positions when it is not advantageous to do so. However, any potential risk of leverage resulting from the use of securities with maturities greater than one year may be mitigated by the overall duration limit on the Fund’s portfolio securities. Thus, the use of a longer term security may require the Fund to hold offsetting short-term securities to balance the Fund’s portfolio such that the Fund’s duration does not exceed the maximum permitted for the Fund in the Prospectus.

The Fund will only enter into futures contracts and futures options which are standardized and traded on a U.S. or foreign exchange, board of trade, or similar entity, or quoted on an automated quotation system, or in the case of futures options, for which an established over-the-counter market exists.

The requirements for qualification as a regulated investment company also may limit the extent to which the Fund may enter into futures, futures options or forward contracts.

Commodity Pool Operators and Commodity Trading Advisors. The CFTC has adopted regulations that subject registered investment companies and their investment advisers to regulation by the CFTC if the registered investment company invests more than a prescribed level of its liquidation value in futures, options on futures or commodities, swaps, or other financial instruments regulated under the Commodity Exchange Act (“commodity interests”), or if the Fund markets itself as providing investment exposure to such instruments. The Investment Manager is registered with the CFTC and as a “commodity pool operator” (“CPO”) under the Commodity Exchange Act with respect to the Fund, and is a member of the National Futures Association in such capacity. Under CFTC rules, certain mandated disclosure, reporting and recordkeeping obligations will apply to the Investment Manager with respect to the Fund. Compliance with the CFTC’s regulatory requirements could increase the Fund’s expenses, adversely affecting the Fund’s total return.

Risks Associated with Futures and Futures Options. There are several risks associated with the use of futures contracts and futures options as hedging techniques. A purchase or sale of a futures contract may result in losses in excess of the amount invested in the futures contract. Some of the risk may be caused by an imperfect correlation between movements in the price of the futures contract and the price of the security or other investment being hedged. The hedge will not be fully effective where there is such imperfect correlation. Also, an incorrect correlation could result in a loss on both the hedged securities in the Fund and the hedging vehicle, so that the portfolio return might have been greater had hedging not been attempted. For example, if the price of the futures contract moves more than the price of the hedged security, the Fund would experience either a loss or gain on the future which is not completely offset by movements in the price of the hedged securities. In addition, there are significant differences between the securities and futures markets that could result in an imperfect correlation between the markets, causing a given hedge not to achieve its objective. The degree of imperfection of correlation depends on circumstances such as variations in speculative market demand for futures and futures options on securities, including technical influences in futures trading and futures options, and differences between the financial instruments being hedged and the instruments underlying the standard contracts available for trading in such respects as interest rate levels, maturities, and creditworthiness of issuers. To compensate for imperfect correlations, the Fund may purchase or sell futures contracts in a greater dollar amount than the hedged securities if the volatility of the hedged securities is historically greater than the volatility of the futures contracts. Conversely, the Fund may purchase or sell fewer contracts if the volatility of the price of the hedged securities is historically less than that of the futures contracts. The risk of imperfect correlation generally tends to diminish as the maturity date of the futures contract approaches. A decision as to whether, when and how to hedge involves the exercise of skill and judgment, and even a well-conceived hedge may be unsuccessful to some degree because of market behavior or unexpected interest rate trends. Also, suitable hedging transactions may not be available in all circumstances.

Additionally, the price of Index Futures may not correlate perfectly with movement in the relevant index due to certain market distortions. First, all participants in the futures market are subject to margin deposit and maintenance requirements. Rather than meeting additional margin deposit requirements, investors may close futures contracts through offsetting transactions which could distort the normal relationship between the index and futures markets. Second, the deposit requirements in the futures market are less onerous than margin requirements in the securities market, and as a result, the futures market may attract more speculators than does the securities market. Increased participation by speculators in the futures market may also cause temporary price

distortions. In addition, trading hours for foreign stock Index Futures may not correspond perfectly to hours of trading on the foreign exchange to which a particular foreign stock Index Future relates. This may result in a disparity between the price of Index Futures and the value of the relevant index due to the lack of continuous arbitrage between the Index Futures price and the value of the underlying index.

Futures exchanges may limit the amount of fluctuation permitted in certain futures contract prices during a single trading day. The daily limit establishes the maximum amount that the price of a futures contract may vary either up or down from the previous day’s settlement price at the end of the current trading session. Once the daily limit has been reached in a futures contract subject to the limit, no more trades may be made on that day at a price beyond that limit. The daily limit governs only price movements during a particular trading day and therefore does not limit potential losses because the limit may work to prevent the liquidation of unfavorable positions. For example, futures prices have occasionally moved to the daily limit for several consecutive trading days with little or no trading, thereby preventing prompt liquidation of positions and subjecting some holders of futures contracts to substantial losses.

There can be no assurance that a liquid market will exist at a time when the Fund seeks to close out a futures or a futures option position, and that the Fund would remain obligated to meet margin requirements until the position is closed. In addition, many of the contracts discussed above are relatively new instruments without a significant trading history. As a result, there can be no assurance that an active secondary market will develop or continue to exist.

Risks Associated with Commodity Futures Contracts. There are several additional risks associated with transactions in commodity futures contracts.

Storage. Unlike the financial futures markets, in the commodity futures markets there are costs of physical storage associated with purchasing the underlying commodity. The price of the commodity futures contract will reflect the storage costs of purchasing the physical commodity, including the time value of money invested in the physical commodity. To the extent that the storage costs for an underlying commodity change while the Fund is invested in futures contracts on that commodity, the value of the futures contract may change proportionately.

Reinvestment. In the commodity futures markets, producers of the underlying commodity may decide to hedge the price risk of selling the commodity by selling futures contracts today to lock in the price of the commodity at delivery tomorrow. In order to induce speculators to purchase the other side of the same futures contract, the commodity producer generally must sell the futures contract at a lower price than the expected future spot price. Conversely, if most hedgers in the futures market are purchasing futures contracts to hedge against a rise in prices, then speculators will only sell the other side of the futures contract at a higher futures price than the expected future spot price of the commodity. The changing nature of the hedgers and speculators in the commodity markets will influence whether futures prices are above or below the expected future spot price, which can have significant implications for the Fund. If the nature of hedgers and speculators in futures markets has shifted when it is time for the Fund to reinvest the proceeds of a maturing contract in a new futures contract, the Fund might reinvest at higher or lower futures prices, or choose to pursue other investments.

Other Economic Factors. The commodities which underlie commodity futures contracts may be subject to additional economic and non-economic variables, such as drought, floods, weather, livestock disease, embargoes, tariffs, and international economic, political and regulatory developments. These factors may have a larger impact on commodity prices and commodity-linked instruments, including futures contracts, than on traditional securities. Certain commodities are also subject to limited pricing flexibility because of supply and demand factors. Others are subject to broad price fluctuations as a result of the volatility of the prices for certain raw materials and the instability of supplies of other materials. These additional variables may create additional investment risks which subject the Fund’s investments to greater volatility than investments in traditional securities.

Additional Risks of Options on Securities, Futures Contracts, Options on Futures Contracts and Forward Currency Exchange Contracts and Options Thereon. Options on securities, futures contracts, options on futures contracts, and options on currencies may be traded on non-U.S. exchanges. Such transactions may not be regulated as effectively as similar transactions in the United States; may not involve a clearing mechanism and related guarantees; and are subject to the risk of governmental actions affecting trading in, or the prices of, non-U.S. securities. Some non-U.S. exchanges may be principal markets so that no common clearing facility exists and a trader may look only to the broker for performance of the contract. The value of such positions also could be adversely affected by (i) other complex non-U.S. political, legal and economic factors, (ii) lesser availability than in the United States of data on which to make trading decisions, (iii) delays in the Fund’s ability to act upon economic events occurring in non-U.S. markets during non-business hours in the United States, (iv) the imposition of different exercise and settlement terms and procedures and margin requirements than in the United States and (v) lesser trading volume. In addition, to the extent that the Fund does not hedge against fluctuations in the exchange rate between the U.S. dollar and the currencies in which trading is done on non-U.S. exchanges, any profits that the Fund might realize in trading could be eliminated by adverse changes in the exchange rate, or the Fund could incur losses as a result of those changes. The value of some derivative instruments in which the Fund may invest may be particularly sensitive to changes in prevailing interest rates, and, like the other investments of the Fund, the ability of the Fund to successfully utilize these instruments may depend in part upon the ability of PIMCO to forecast interest rates and other economic factors correctly. If PIMCO incorrectly forecasts such factors and has taken positions in derivative instruments contrary to prevailing market trends, the Fund could suffer losses. In addition, the Fund’s use of such instruments may cause the Fund to realize higher amounts of short-term capital gains (generally taxed to shareholders at ordinary income tax rates) than if the Fund had not used such instruments.

Swap Agreements and Options on Swap Agreements. The Fund may engage in swap transactions, including, but not limited to, swap agreements on interest rates, security or commodity indexes, specific securities and commodities, and credit and event-linked swaps. To the extent the Fund may invest in foreign currency denominated securities, it may also invest in currency exchange rate swap agreements. The Fund may also enter into options on swap agreements (“swaptions”).

The Fund may enter into swap transactions for any legal purpose consistent with its investment objective and policies, such as attempting to obtain or preserve a particular return or spread at a lower cost than obtaining a return or spread through purchases and/or sales of instruments in other markets, to protect against currency fluctuations, as a duration management technique, to protect against any increase in the price of securities the Fund anticipates purchasing at a later date, or to gain exposure to certain markets in a more cost-efficient manner.

Swap agreements are bilateral contracts entered into primarily by institutional investors for periods ranging from a few weeks to a number of years. Swap agreements are individually negotiated and structured to include exposure to a variety of types of investments or market factors. In a standard “swap” transaction, two parties agree to exchange the returns (or differentials in rates of return) earned or realized on particular predetermined investments or instruments, which may be adjusted for an interest factor. The gross returns to be exchanged or “swapped” between the parties are generally calculated with respect to a “notional amount,” such as the return on or increase in value of a particular dollar amount invested at a particular interest rate, in a particular foreign currency, or in a “basket” of securities or commodities representing a particular index. Forms of swap agreements include interest rate caps, under which, in return for a premium, one party agrees to make payments to the other to the extent that interest rates exceed a specified rate, or “cap”; interest rate floors, under which, in return for a premium, one party agrees to make payments to the other to the extent that interest rates fall below a specified rate, or “floor”; and interest rate collars, under which a party sells a cap and purchases a floor or vice versa in an attempt to protect itself against interest rate movements exceeding given minimum or maximum levels. Consistent with the Fund’s investment objective and general investment policies, certain of the Fund may invest in commodity swap agreements. For example, an investment in a commodity swap agreement may involve the exchange of floating-rate interest payments for the total return on a commodity index. In a total return commodity swap, the Fund will receive the price appreciation of a commodity index, a portion of the index, or a single commodity in exchange for paying an agreed-upon fee. If the commodity swap is for one period, the Fund may pay a fixed fee, established at the outset of the swap. However, if the term of the commodity swap is more than one period, with interim swap payments, the Fund may pay an adjustable or floating fee. With a “floating” rate, the fee may be pegged to a base rate, such as the London Interbank Offered Rate, and is adjusted each period. Therefore, if interest rates increase over the term of the swap contract, the Fund may be required to pay a higher fee at each swap reset date.

A swaption is a contract that gives a counterparty the right (but not the obligation) in return for payment of a premium, to enter into a new swap agreement or to shorten, extend, cancel or otherwise modify an existing swap agreement, at some designated future time on specified terms. The Fund may write (sell) and purchase put and call swaptions.

Most swap agreements entered into by the Fund would calculate the obligations of the parties to the agreement on a “net basis.” Consequently, the Fund’s current obligations (or rights) under a swap agreement will generally be equal only to the net amount to be paid or received under the agreement based on the relative values of the positions held by each party to the agreement (the “net amount”). The Fund’s current obligations under a swap agreement will be accrued daily (offset against any amounts owed to the Fund) and any accrued but unpaid net amounts owed to a swap counterparty will be covered by the segregation of assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees, to avoid any potential leveraging of the Fund’s portfolio. Obligations under swap agreements so covered will not be construed to be “senior securities” for purposes of the Fund’s investment restriction concerning senior securities and borrowings.

The Fund also may enter into OTC and cleared credit default swap agreements. The credit default swap agreement may reference one or more debt securities or obligations that are not currently held by the Fund. The protection “buyer” in an OTC credit default contract is generally obligated to pay the protection “seller” an upfront or a periodic stream of payments over the term of the contract until a credit event, such as a default, on a reference obligation has occurred. If a credit event

occurs, the seller generally must pay the buyer the “par value” (full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount if the swap is cash settled. The Fund may be either the buyer or seller in the transaction. If the Fund is a buyer and no credit event occurs, the Fund may recover nothing if the swap is held through its termination date. However, if a credit event occurs, the buyer may receive the full notional value of the swap in exchange for an equal face amount of deliverable obligations of the reference entity whose value may have significantly decreased.

As a seller, the Fund generally receives an upfront payment or a fixed rate of income throughout the term of the swap provided that there is no credit event. As the seller, the Fund would effectively add leverage to its portfolio because, in addition to its total net assets, the Fund would be subject to investment exposure on the notional amount of the swap.

The spread of a credit default swap is the annual amount the protection buyer must pay the protection seller over the length of the contract, expressed as a percentage of the notional amount. When spreads rise, market perceived credit risk rises and when spreads fall, market perceived credit risk falls. Wider credit spreads and decreasing market values, when compared to the notional amount of the swap, represent a deterioration of the credit soundness of the issuer of the reference obligation and a greater likelihood or risk of default or other credit event occurring as defined under the terms of the agreement. For credit default swap agreements on asset-backed securities and credit indices, the quoted market prices and resulting values, as well as the annual payment rate, serve as an indication of the current status of the payment/performance risk.

Credit default swap agreements sold by the Fund may involve greater risks than if the Fund had invested in the reference obligation directly since, in addition to general market risks, credit default swaps are subject to illiquidity risk, and with respect to OTC credit default swaps, counterparty risk and credit risk. The Fund will enter into uncleared credit default swap agreements only with counterparties that meet certain standards of creditworthiness. A buyer generally also will lose its investment and recover nothing should no credit event occur and the swap is held to its termination date. If a credit event were to occur, the value of any deliverable obligation received by the seller, coupled with the upfront or periodic payments previously received, may be less than the full notional value it pays to the buyer, resulting in a loss of value to the seller. The Fund’s obligations under a credit default swap agreement will be accrued daily (offset against any amounts owing to the Fund). In connection with credit default swaps in which the Fund is the buyer, if the Fund covers its position through asset segregation, the Fund will segregate or “earmark” cash or assets determined to be liquid by PIMCO in accordance with procedures established by the Board of Trustees, or enter into certain offsetting positions, with a value at least equal to the Fund’s exposure (any accrued but unpaid net amounts owed by the Fund to any counterparty), on a mark-to-market basis . In connection with credit default swaps in which the Fund is the seller, if the Fund covers its position through asset segregation, the Fund will segregate or “earmark” cash or assets determined to be liquid by PIMCO in accordance with procedures established by the Board of Trustees, with a value at least equal to the full notional amount of the Fund’s obligation under the swap. Such segregation or “earmarking” seeks to ensure that the Fund has assets available to satisfy its obligations with respect to the transaction and could have the effect of limiting any potential leveraging of the Fund’s portfolio. Such segregation or “earmarking” will not limit the Fund’s exposure to loss.

Recent legislative and regulatory reforms, including the Dodd-Frank Wall Street Reform and Consumer Protection Act (the “Dodd-Frank Act”), have resulted in new regulation of swap agreements, including clearing, margin, reporting, recordkeeping and registration requirements for certain types of swaps contracts and other derivatives, including among others interest rate swaps and credit default swaps. Because these requirements are new and evolving, and certain of the rules are not yet final, its ultimate impact remains unclear. New regulations could, among other things, restrict the Fund’s ability to engage in swap transactions (for example, by making certain types of swap transactions no longer available to the Fund) and/or increase the costs of such swap transactions (for example, by increasing margin or capital requirements), and the Fund may as a result be unable to execute its investment strategies in a manner PIMCO might otherwise choose. New rules under the Dodd-Frank Act require certain over-the-counter derivatives, including certain interest rate swaps and certain credit default swaps, to be executed on a regulated market and cleared through a central counterparty, which may result in increased margin requirements and costs for the Fund. It is also unclear how the regulatory changes will affect counterparty risk. See “Risks of Potential Government Regulation of Derivatives” and “Additional Risk Factors in Cleared Derivatives Transactions” below for further detail.

Additionally, U.S. regulators recently issued final rules under the Dodd-Frank Act that establish minimum margin and capital requirements for uncleared OTC derivatives transactions that will have a material impact on the Fund’s use of uncleared derivatives. These rules will impose minimum margin requirements on derivatives transactions between the Fund and their swap counterparties and may increase the amount of margin the Fund is required to provide. They will impose regulatory requirements on the timing of transferring margin, which may accelerate the Fund’s current margin process. They will also effectively require changes to typical derivatives margin documentation.

Whether the Fund’s use of swap agreements or swaptions will be successful in furthering its investment objective will depend on PIMCO’s ability to predict correctly whether certain types of investments are likely to produce greater returns than other investments. Moreover, the Fund bears the risk of loss of the amount expected to be received under a swap agreement in the event of the default or bankruptcy of a swap agreement counterparty. The Fund will enter into OTC swap agreements only with counterparties that meet certain standards of creditworthiness. Certain restrictions imposed on the Fund by the Code may limit the Fund’s ability to use swap agreements. It is possible that developments in the swaps market, including additional government regulation, could adversely affect the Fund’s ability to terminate existing swap agreements or to realize amounts to be received under such agreements.

Like most other investments, swap agreements are subject to the risk that the market value of the instrument will change in a way detrimental to the Fund’s interest. The Fund bears the risk of future market trends or the values of assets, reference rates, indexes, or other economic factors. If the Fund uses a swap as a hedge against, or as a substitute for, a portfolio investment, the Fund will be exposed to the risk that the swap will have or will develop imperfect or no correlation with the portfolio investment. This could cause substantial losses for the Fund. While hedging strategies involving swap instruments can reduce the risk of loss, they can also reduce the opportunity for gain or even result in losses by offsetting favorable price movements in other Fund investments.

Many swaps are complex and often valued subjectively. Many over-the-counter derivatives are complex and their valuation often requires modeling and judgment, which increases the risk of mispricing or incorrect valuation. The pricing models used may not produce valuations that are

consistent with the values the Fund realizes when it closes or sells an over-the-counter derivative. Valuation risk is more pronounced when the Fund enters into over-the-counter derivatives with specialized terms because the market value of those derivatives in some cases is determined in part by reference to similar derivatives with more standardized terms. Incorrect valuations may result in increased cash payment requirements to counterparties, undercollateralization and/or errors in calculation of the Fund’s net asset value.

Swaps are highly specialized instruments that require investment techniques, risk analyses, and tax planning different from those associated with traditional investments. The use of a swap requires an understanding not only of the referenced asset, reference rate, or index but also of the swap itself, without the benefit of observing the performance of the swap under all possible market conditions. Swap agreements may be subject to liquidity risk, which exists when a particular swap is difficult to purchase or sell. If a swap transaction is particularly large or if the relevant market is illiquid (as is the case with many OTC swaps), it may not be possible to initiate a transaction or liquidate a position at an advantageous time or price, which may result in significant losses.

Because OTC swap agreements are bilateral contracts that may be subject to contractual restrictions on transferability and because they may have terms of greater than seven days, swap agreements may be considered to be illiquid. To the extent that a swap is not liquid, it may not be possible to initiate a transaction or liquidate a position at an advantageous time or price, which may result in significant losses.

Moreover, the Fund bears the risk of loss of the amount expected to be received under a swap agreement in the event of the default or bankruptcy of a swap agreement counterparty. The Fund will enter into swap agreements only with counterparties that meet certain standards of creditworthiness. When a counterparty’s obligations are not fully secured by collateral, then the Fund is essentially an unsecured creditor of the counterparty. If the counterparty defaults, the Fund will have contractual remedies, but there is no assurance that a counterparty will be able to meet its obligations pursuant to such contracts or that, in the event of default, the Fund will succeed in enforcing contractual remedies. Counterparty risk still exists even if a counterparty’s obligations are secured by collateral because the Fund’s interest in collateral may not be perfected or additional collateral may not be promptly posted as required. Counterparty risk also may be more pronounced if a counterparty’s obligations exceed the amount of collateral held by the Fund (if any), the Fund is unable to exercise its interest in collateral upon default by the counterparty, or the termination value of the instrument varies significantly from the marked-to-market value of the instrument.

Depending on the terms of the particular option agreement, the Fund will generally incur a greater degree of risk when it writes a swaption than it will incur when it purchases a swaption. When the Fund purchases a swaption, it risks losing only the amount of the premium it has paid should it decide to let the option expire unexercised. However, when the Fund writes a swaption, upon exercise of the option the Fund will become obligated according to the terms of the underlying agreement.

Title VII of the Dodd-Frank Act establishes a framework for the regulation of the OTC swap markets outlining the joint responsibility of the CFTC and the SEC in regulating swaps. The CFTC is responsible for the regulation of swaps, the SEC is responsible for the regulation of security-based swaps and jointly they are both responsible for the regulation of mixed swaps.

Structured Notes. The Fund may invest in “structured” notes, which are privately negotiated debt obligations where the principal and/or interest is determined by reference to the performance of a benchmark asset, market or interest rate, such as selected securities, an index of securities or specified interest rates, or the differential performance of two assets or markets, such as indexes reflecting bonds. Depending on the terms of the note, the Fund may forgo all or part of the interest and principal that would be payable on a comparable conventional note. The rate of return on structured notes may be determined by applying a multiplier to the performance or differential performance of the referenced index(es) or other asset(s). Application of a multiplier involves leverage which will serve to magnify the potential for gain and the risk of loss. The Fund may use structured notes to add leverage to the portfolio and for investment as well as risk management purposes. Like other sophisticated strategies, the Fund’s use of structured notes may not work as intended.

Risks of Potential Government Regulation of Derivatives. It is possible that government regulation of various types of derivative instruments, including futures and swap agreements, may limit or prevent the Fund from using such instruments as a part of its investment strategy, and could ultimately prevent the Fund from being able to achieve its investment objective. It is impossible to fully predict the effects of past, present or future legislation and regulation in this area, but the effects could be substantial and adverse.

The futures markets are subject to comprehensive statutes, regulations, and margin requirements. In addition, the SEC, CFTC and the exchanges are authorized to take extraordinary actions in the event of a market emergency, including, for example, the implementation or reduction of speculative position limits, the implementation of higher margin requirements, the establishment of daily price limits and the suspension of trading.

The regulation of swaps and futures transactions in the U.S. is a rapidly changing area of law and is subject to modification by government and judicial action. There is a possibility of future regulatory changes altering, perhaps to a material extent, the nature of an investment in the Fund or the ability of the Fund to continue to implement its investment strategies. In particular, the Dodd-Frank Act sets forth a legislative framework for OTC derivatives, such as swaps, in which the Fund may invest. Title VII of the Dodd-Frank Act makes broad changes to the OTC derivatives market, grants significant new authority to the SEC and the CFTC to regulate OTC derivatives and market participants, and, among other things, requires clearing of many OTC derivatives transactions and imposes minimum margin and capital requirements on uncleared OTC derivatives transactions.

In addition, in December 2015, the SEC proposed new regulations applicable to registered investment companies’ use of derivatives and related instruments. If adopted as proposed, these regulations could significantly limit or impact the Fund’s ability to invest in derivatives and other instruments, limit the Fund’s ability to employ certain strategies that use such instruments and/or adversely affect the Fund’s performance, efficiency in implementing its strategy, liquidity and/or ability to pursue its investment objective.

Additional Risk Factors in Cleared Derivatives Transactions. Under recently adopted rules and regulations, transactions in some types of swaps (including interest rate swaps and credit default index swaps on North American and European indices) are required to be centrally cleared, and additional types of swaps may be required to be centrally cleared in the future. In a cleared derivatives transaction, the Fund’s counterparty is a clearing house, rather than a bank or broker. Since the Fund is not a member of clearing houses and only members of a clearing house can

participate directly in the clearing house, the Fund will hold cleared derivatives through accounts at clearing members. In cleared derivatives transactions, the Fund will make payments (including margin payments) to and receive payments from a clearing house through their accounts at clearing members. Clearing members guarantee performance of their clients’ obligations to the clearing house.

In many ways, centrally cleared derivative arrangements are less favorable to mutual funds than bilateral arrangements. For example, the Fund may be required to provide greater amounts of margin for cleared derivatives transactions than for bilateral derivatives transactions. Also, in contrast to bilateral derivatives transactions, following a period of notice to the Fund, a clearing member generally can require termination of existing cleared derivatives transactions at any time or increases in margin requirements above the margin that the clearing member required at the beginning of a transaction. Clearing houses also have broad rights to increase margin requirements for existing transactions or to terminate transactions at any time. Any increase in margin requirements or termination by the clearing member or the clearing house could interfere with the ability of the Fund to pursue its investment strategy. Further, any increase in margin requirements by a clearing member could also expose the Fund to greater credit risk to its clearing member, because margin for cleared derivatives transactions in excess of clearing house margin requirements typically is held by the clearing member. Also, the Fund is subject to risk if it enters into a derivatives transaction that is required to be cleared (or that PIMCO expects to be cleared), and no clearing member is willing or able to clear the transaction on the Fund’s behalf. While the documentation in place between the Fund and its clearing members generally provides that the clearing members will accept for clearing all transactions submitted for clearing that are within credit limits (specified in advance) for the Fund, the Fund is still subject to the risk that no clearing member will be willing or able to clear a transaction. In those cases, the transaction might have to be terminated, and the Fund could lose some or all of the benefit of the transaction, including loss of an increase in the value of the transaction and/or loss of hedging protection offered by the transaction. In addition, the documentation governing the relationship between the Fund and the clearing members is developed by the clearing members and generally is less favorable to the Fund than typical bilateral derivatives documentation. For example, this documentation generally includes a one-way indemnity by the Fund in favor of the clearing member, indemnifying the clearing member against losses it incurs in connection with acting as the Fund’s clearing member, and the documentation typically does not give the Fund any rights to exercise remedies if the clearing member defaults or becomes insolvent.

Some types of cleared derivatives are required to be executed on an exchange or on a swap execution facility (a “SEF”). A SEF is a trading platform where multiple market participants can execute derivatives by accepting bids and offers made by multiple other participants in the platform. This execution requirement may make it more difficult and costly for funds, such as the Fund, to enter into highly tailored or customized transactions. Trading swaps on a SEF may offer certain advantages over traditional bilateral over-the-counter trading, such as ease of execution, price transparency, increased liquidity and/or favorable pricing. Execution through a SEF is not, however, without additional costs and risks, as parties are required to comply with SEF and CFTC rules and regulations, including disclosure and recordkeeping obligations, and SEF rights of inspection, among others. SEFs typically charge fees, and if the Fund executes derivatives on a swap execution facility through a broker intermediary, the intermediary may impose fees as well. The Fund also may be required to indemnify a SEF, or a broker intermediary who executes swaps on a SEF on the Fund’s behalf, against any losses or costs that may be incurred as a result of the Fund’s transactions on the SEF. In addition, the Fund may be subject to execution risk if it enters

into a derivatives transaction that is required to be cleared, and no clearing member is willing to clear the transaction on the Fund’s behalf. In that case, the transaction might have to be terminated, and the Fund could lose some or all of the benefit of any increase in the value of the transaction after the time of the trade.

These and other new rules and regulations could, among other things, further restrict the Fund’s ability to engage in, or increase the cost to the Fund of, derivatives transactions, for example, by making some types of derivatives no longer available to the Fund, increasing margin or capital requirements, or otherwise limiting liquidity or increasing transaction costs. These regulations are new and evolving, so their potential impact on the Fund and the financial system are not yet known. While the new regulations and the central clearing of some derivatives transactions are designed to reduce systemic risk (i.e., the risk that the interdependence of large derivatives dealers could cause a number of those dealers to suffer liquidity, solvency or other challenges simultaneously), there is no assurance that the new clearing mechanisms will achieve that result, and in the meantime, as noted above, central clearing will expose the Fund to new kinds of risks and costs.

A Note on Commodity-Linked Derivatives. The Fund may seek to gain exposure to the commodity markets by investing in commodity-linked derivative instruments, swap transactions, or index-linked or commodity linked structured notes. The value of a commodity-linked derivative investment generally is based upon the price movements of a physical commodity (such as energy, mineral, or agricultural products), a commodity futures contract or commodity index, or other economic variable based upon changes in the value of commodities or the commodities markets. Swap transactions are privately negotiated agreements between the Fund and a counterparty to exchange or swap investment cash flows or assets at specified intervals in the future. The obligations may extend beyond one year. There is no central exchange or market for swap transactions and therefore they are less liquid investments than exchange-traded instruments. The Fund bears the risk that the counterparty could default under a swap agreement. See “Swap Agreements and Options on Swap Agreements” above for further detail about swap transactions. Further, the Fund may invest in derivative debt instruments with principal and/or coupon payments linked to the value of commodities, commodity futures contracts or the performance of commodity indices. These are “commodity-linked” or “index-linked” notes, and are sometimes referred to as “structured notes” because the terms of the debt instrument may be structured by the issuer of the note and the purchaser of the note. See “Structured Notes” above for further discussion of these notes.

The value of these notes will rise or fall in response to changes in the underlying commodity or related index of investment. These notes expose the Fund economically to movements in commodity prices. These notes also are subject to risks, such as credit, market and interest rate risks, that in general affect the values of debt securities. Therefore, at the maturity of the note, the Fund may receive more or less principal that it originally invested. The Fund might receive interest payments on the note that are more or less than the stated coupon interest payments. The Fund’s investments in commodity-linked instruments may bear on or be limited by the Fund’s intention to qualify as a regulated investment company under the Code. See “Taxation.”

Asset Segregation. Certain of the transactions described above can be viewed as constituting a form of borrowing or financing transaction by the Fund. In such event, the Fund will cover its commitment under such transactions by segregating or “earmarking” assets in accordance with procedures adopted by the Board of Trustees, in which case such transactions will not be considered “senior securities” by the Fund. With respect to forwards and futures contracts, and interest rate

swaps that are contractually required to cash settle (i.e., where physical delivery of the underlying reference asset is not permitted or physical settlement is not otherwise involved), the Fund is permitted to segregate or earmark liquid assets equal to the Fund’s daily marked-to-market net obligation under the derivative instrument, if any, rather than the derivative’s full notional value, but will segregate full notional value, as applicable, with respect to other derivative instruments (including written credit default swaps and written options) that contractually require or permit physical delivery of securities or other underlying assets. By segregating or earmarking liquid assets equal to only its net marked-to-market obligation under forwards and futures contracts and interest rate swaps that are required to cash settle, the Fund will have the ability to employ leverage to a greater extent than if the Fund were to segregate or earmark liquid assets equal to the full notional value of such derivatives.

The Fund may invest in “hybrid” or indexed securities, which is a type of potentially high-risk derivative that combines a traditional stock, bond, or commodity with an option or forward contract. Generally, the principal amount, amount payable upon maturity or redemption, or interest rate of a hybrid is tied (positively or negatively) to the price of some commodity, currency or securities index or another interest rate or some other economic factor (each a “benchmark”). The interest rate or (unlike most fixed income securities) the principal amount payable at maturity of a hybrid security may be increased or decreased, depending on changes in the value of the benchmark. An example of a hybrid could be a bond issued by an oil company that pays a small base level of interest with additional interest that accrues in correlation to the extent to which oil prices exceed a certain predetermined level. Such a hybrid instrument would be a combination of a bond and a call option on oil.

Certain hybrid instruments may provide exposure to the commodities markets. These are derivative securities with one or more commodity-linked components that have payment features similar to commodity futures contracts, commodity options, or similar instruments. Commodity-linked hybrid instruments may be either equity or fixed income securities and are considered hybrid instruments because they have both security and commodity-like characteristics. A portion of the value of these instruments may be derived from the value of a commodity, futures contract, index or other economic variable. The Fund will only invest in commodity-linked hybrid instruments that qualify under applicable rules of the CFTC for an exemption from the provisions of the CEA.

Certain issuers of structured products such as hybrid instruments may be deemed to be investment companies, as defined in the 1940 Act. As a result, the Fund’s investments in these products may be subject to limits applicable to investments in investment companies and may be subject to other restrictions imposed by the 1940 Act. In addition, the Fund’s investments in these products may be limited by the Fund’s intention to qualify as a regulated investment company, and may limit the Fund’s ability to so qualify.

The Fund utilizes leverage through its outstanding preferred shares (“Preferred Shares”) and may obtain additional leverage through reverse repurchase agreements dollar rolls or borrowings, such as through bank loans or commercial paper and/or other credit facilities. The amount of leverage the Fund utilizes may vary, but the Fund will not incur leverage (including preferred shares and other forms of leverage) in an amount exceeding 50% of its total assets. Information regarding the terms and features of the Preferred Shares is provided under “Description of Capital Structure” in the prospectus.

Depending upon market conditions and other factors, the Fund may or may not determine to add leverage following an offering to maintain or increase the total amount of leverage (as a percentage of the Fund’s total assets) that the Fund currently maintains, taking into account the additional assets raised through the issuance of Common Shares in such offering. The Fund utilizes certain kinds of leverage, such as reverse repurchase agreements and credit default swaps, opportunistically and may choose to increase or decrease, or eliminate entirely, its use of such leverage over time and from time to time based on PIMCO’s assessment of the yield curve environment, interest rate trends, market conditions and other factors. The Fund may also determine to decrease the leverage it currently maintains through its outstanding Preferred Shares through Preferred Shares redemptions or tender offers and may or may not determine to replace such leverage through other sources. If the Fund determines to add leverage following an offering, it is not possible to predict with accuracy the precise amount of leverage that would be added, in part because it is not possible to predict the number of Common Shares that ultimately will be sold in an offering or series of offerings. To the extent that the Fund does not add additional leverage following an offering, the Fund’s total amount of leverage as a percentage of its total assets will decrease, which could result in a reduction of investment income available for distribution to Common Shareholders.

The Fund’s net assets attributable to its Preferred Shares and the net proceeds the Fund obtains from reverse repurchase agreements, dollar rolls, or other forms of leverage utilized, if any, will be invested in accordance with the Fund’s investment objective and policies as described in the Prospectus and any prospectus supplement. So long as the rate of return, net of applicable Fund expenses, on the debt obligations and other investments purchased by the Fund exceeds the dividend rates payable on the Preferred Shares together with the costs to the Fund of other leverage it utilizes, the investment of the Fund’s assets attributable to leverage will generate more income than will be needed to pay the costs of the leverage. If so, and all other things being equal, the excess may be used to pay higher dividends to Common Shareholders than if the Fund were not so leveraged.

Regarding the costs associated with the Fund’s Preferred Shares, the terms of the Fund’s auction rate preferred shares (“ARPS”) provide that they would ordinarily pay dividends at a rate set at auctions held every seven days, normally payable on the first business day following the end of the rate period, subject to a maximum applicable rate calculated as a function of the ARPS’ then-current rating and a reference interest rate, as described below. However, the weekly auctions for the ARPS, as well as auctions for similar preferred shares of other closed-end funds in the U.S., have failed since February 2008, and the dividend rates on the ARPS since that time have been paid at the maximum applicable rate (i.e. a multiple of a reference rate, which is the applicable “AA” Financial Composite Commercial Paper Rate (for a dividend period of fewer than 184 days) or the applicable Treasury Index Rate (for a dividend period of 184 days or more)). In September 2011, Moody’s, a ratings agency that provides ratings for the Fund’s ARPS, downgraded its rating of the ARPS from “Aaa” to “A2,” citing persistently thin asset coverage levels, increased NAV volatility and concerns about secondary market liquidity for some assets supporting rated obligations. In July 2012, Moody’s downgraded its rating of the ARPS from “A2” to “A3” pursuant to a revised ratings methodology adopted by Moody’s. Also, in May 2014, Moody’s upgraded its rating of the Fund’s ARPS from A3 to A2, citing changes in the Fund’s asset coverage ratio and economic leverage. Under the Fund’s amended and restated bylaws (the “Bylaws”), the 2011 downgrade resulted in an increase in the multiple used to calculate the maximum applicable rate from 150% to 200%, thereby increasing the dividend rate payable to ARPS holders and increasing the expenses to Common Shareholders associated with the Fund’s leverage. See “Description of Capital Structure.” The Fund expects that the ARPS will continue to pay dividends at the maximum applicable rate for the foreseeable future and cannot predict whether or when the auction markets for the ARPS may resume normal functioning. See “Principal Risks of the Fund—Leverage Risk,” “Principal Risks of the Fund—Additional Risks Associated with the Fund’s Preferred Shares” and “Description of Capital Structure” in the Prospectus for more information.

Under the 1940 Act, the Fund is not permitted to issue new preferred shares unless immediately after such issuance the value of the Fund’s total net assets (as defined below) is at least 200% of the liquidation value of the outstanding Preferred Shares and the newly issued preferred shares plus the aggregate amount of any senior securities of the Fund representing indebtedness (i.e., such liquidation value plus the aggregate amount of senior securities representing indebtedness may not exceed 50% of the Fund’s total net assets). In addition, the Fund is not permitted to declare any cash dividend or other distribution on its Common Shares unless, at the time of such declaration, the value of the Fund’s total net assets satisfies the above-referenced 200% coverage requirement.

To the extent that the Fund maintains segregated assets or otherwise covers certain of these instruments, they will not be considered “senior securities” under the 1940 Act and therefore will not be subject to the 1940 Act 300% asset coverage requirement otherwise applicable to forms of senior securities representing indebtedness used by the Fund. However, reverse repurchase agreements, dollar rolls and other such instruments, even if covered, represent a form of economic leverage and create special risks. The use of these forms of leverage increases the volatility of the Fund’s investment portfolio and could result in larger losses to Common Shareholders than if these strategies were not used. To the extent that the Fund engages in borrowings, it may prepay a portion of the principal amount of the borrowing to the extent necessary in order to maintain the required asset coverage. Failure to maintain certain asset coverage requirements could result in an event of default.

Leveraging is a speculative technique and there are special risks and costs involved. The Fund cannot assure you that its Preferred Shares and use of any other forms of leverage (such as the use of reverse repurchase agreements or derivatives strategies), if any, will result in a higher yield on your Common Shares. When leverage is used, the NAV and market price of the Common Shares and the yield to Common Shareholders will be more volatile. See “Principal Risks of the Fund—Leverage Risk” in the Prospectus. In addition, dividend, interest and other costs and expenses borne by the Fund with respect to its Preferred Shares and its use of any other forms of leverage are borne by the Common Shareholders (and not by the holders of Preferred Shares) and result in a reduction of the NAV of the Common Shares. In addition, because the fees received by the Investment Manager are based on the average daily net assets of the Fund (including any assets attributable to any outstanding Preferred Shares), the Investment Manager has a financial incentive for the Fund to use Preferred Shares, which may create a conflict of interest between the Investment Manager, on the one hand, and the Common Shareholders, on the other hand. The fees received by the Investment Manager are not, however, charged on asset attributable to leverage obtained by the Fund other than through preferred shares.

The Fund’s ability to utilize leverage is also limited by asset coverage requirements and other guidelines imposed by rating agencies (currently Moody’s) that provide ratings for the ARPS, which may be more restrictive than the limitations imposed by the 1940 Act noted above. See “Description of Capital Structure” in the Prospectus for more information.

The SEC has issued a proposed rule relating to a registered investment company’s use of derivatives and related instruments that, if adopted, could potentially require the Fund to reduce its use of leverage and/or observe more stringent asset coverage and related requirements than are currently imposed by the 1940 Act, which could adversely affect the value or performance of the Fund and the Common Shares.

The Fund may borrow money to the extent permitted under the 1940 Act as interpreted, modified or otherwise permitted by regulatory authority having jurisdiction, from time to time. The Fund also may borrow money for temporary administrative purposes, to add leverage to the portfolio or for the settlement of securities transactions which otherwise might require untimely dispositions of portfolio securities held by the Fund.

The Fund may enter into reverse repurchase agreements and economically similar transactions for hedging or cash management purposes or to add leverage to its portfolio. See the sections “Use of Leverage” in the Prospectus and “Leverage and Borrowing” above. A reverse repurchase agreement involves the sale of a portfolio-eligible security by the Fund, coupled with its agreement to repurchase the instrument at a specified time and price. Under a reverse repurchase agreement, the Fund continues to be entitled to receive any principal and interest payments on the underlying security during the term of the agreement. Reverse repurchase agreements involve leverage risk and the risk that the market value of securities retained by the Fund may decline below the repurchase price of the securities sold by the Fund which it is obligated to repurchase. The Fund may (but is not required to) segregate or “earmark” liquid assets equal (on a daily mark-to-market basis) to its obligations under reverse repurchase agreements. To the extent that positions in reverse repurchase agreements are not so covered, they would be deemed senior securities representing indebtedness for purposes of the 1940 Act.

The Fund also may effect simultaneous purchase and sale transactions that are known as “sale-buybacks.” A sale-buyback is similar to a reverse repurchase agreement, except that in a sale-buyback, the counterparty who purchases the security is entitled to receive any principal or interest payments made on the underlying security pending settlement of the Fund’s repurchase of the underlying security.

A mortgage dollar roll is similar to a reverse repurchase agreement in certain respects. In a “dollar roll” transaction, the Fund sells a mortgage-related security, such as a security issued by GNMA, to a dealer and simultaneously agrees to repurchase a similar security (but not the same security) in the future at a pre-determined price. A “dollar roll” can be viewed, like a reverse repurchase agreement, as a collateralized borrowing in which the Fund pledges a mortgage-related security to a dealer to obtain cash. However, unlike reverse repurchase agreements, the dealer with which the Fund enters into a dollar roll transaction is not obligated to return the same securities as those originally sold by the Fund, but only securities which are “substantially identical.” To be considered “substantially identical,” the securities returned to the Fund generally must: (1) be collateralized by the same types of underlying mortgages; (2) be issued by the same agency and be part of the same program; (3) have a similar original stated maturity;

(4) have identical net coupon rates; (5) have similar market yields (and therefore price); and (6) satisfy “good delivery” requirements, meaning that the aggregate principal amounts of the securities delivered and received back must be within a specified percentage of the initial amount delivered.

The Fund’s obligations under a dollar roll agreement must be covered by segregated or “earmarked” liquid assets equal in value to the securities subject to repurchase by the Fund. As with reverse repurchase agreements, to the extent that positions in dollar roll agreements are not covered by segregated or “earmarked” liquid assets at least equal to the amount of any forward purchase commitment, such transactions would be deemed senior securities representing indebtedness for purposes of the 1940 Act and would be subject to the Fund’s restrictions on borrowings. Furthermore, because dollar roll transactions may be for terms ranging between one and six months, dollar roll transactions may be deemed “illiquid” and subject to the Fund’s overall limitations on investments in illiquid securities.

It is possible that changing government regulation may affect the Fund’s use of these strategies. Changes in regulatory requirements concerning margin for certain types of financing transactions, such as repurchase agreements, reverse repurchase agreements, and securities lending and borrowing, could impact the Fund’s ability to utilize these investment strategies and techniques.

For the purposes of maintaining liquidity and achieving income, the Fund may enter into repurchase agreements with domestic commercial banks or registered broker-dealers. A repurchase agreement is a contract under which the Fund would acquire a security for a relatively short period (usually not more than one week) subject to the obligation of the seller to repurchase and the Fund to resell such security at a fixed time and price (representing the Fund’s cost plus interest). In the case of repurchase agreements with broker-dealers, the value of the underlying securities (or collateral) will be at least equal at all times to the total amount of the repurchase obligation, including the interest factor. The Fund bears a risk of loss in the event that the other party to a repurchase agreement defaults on its obligations and the Fund is delayed or prevented from exercising its rights to dispose of the collateral securities. This risk includes the risk of procedural costs or delays in addition to a loss on the securities if their value should fall below their repurchase price. PIMCO will monitor the creditworthiness of the counterparties.

Like an investment in a bond, investments in these credit-linked trust certificates represent the right to receive periodic income payments (in the form of distributions) and payment of principal at the end of the term of the certificate. However, these payments are conditioned on the Fund’s receipt of payments from, and the Fund’s potential obligations to, the counterparties to the derivative instruments and other securities in which the trust invests. For instance, the trust may sell one or more credit default swaps, under which the trust would receive a stream of payments over the term of the swap agreements provided that no event of default has occurred with respect to the referenced debt obligation upon which the swap is based. If a default occurs, the stream of payments may stop and the trust would be obligated to pay to the counterparty the par (or other agreed upon value) of the referenced debt obligation. This, in turn, would reduce the amount of income and principal that the Fund would receive as an investor in the trust. Please see “Derivatives Instruments–Swap Agreements and Options on Swap Agreements” in this Statement of Additional Information for additional information about credit default swaps. The Fund’s investments in these instruments are indirectly subject to the risks associated with derivative instruments, including, among others, credit risk, default or similar event risk, counterparty risk, interest rate risk, leverage risk and management risk. It is expected that the trusts which issue credit-linked trust certificates will constitute “private” investment companies, exempt from registration under the 1940 Act. Therefore, the certificates will be subject to the risks described under “Other Investment

Companies,” and will not be subject to applicable investment limitations and other regulation imposed by the 1940 Act (although the Fund will remain subject to such limitations and regulation, including with respect to its investments in the certificates). Although the trusts are typically private investment companies, they generally are not actively managed such as a “hedge fund” might be. It is also expected that the certificates will be exempt from registration under the 1933 Act. Accordingly, there may be no established trading market for the certificates and they may constitute illiquid investments. See “Principal Risks of the Fund–Liquidity Risk” in the Prospectus. If market quotations are not readily available for the certificates, they will be valued by the Fund at fair value as determined by the Board of Trustees or persons acting at its direction. See “Net Asset Value” in the Prospectus.

The Fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis. When such purchases are outstanding, the Fund will segregate until the settlement date assets determined to be liquid by PIMCO in accordance with the procedures approved by the Board of Trustees in an amount sufficient to meet the purchase price. Typically, no income accrues on securities the Fund has committed to purchase prior to the time delivery of the securities is made, although the Fund may earn income on securities it has segregated.

When purchasing a security on a when-issued, delayed delivery or forward commitment basis, the Fund assumes the rights and risks of ownership of the security, including the risk of price and yield fluctuations, and takes such fluctuations into account when determining its net asset value. Because the Fund is not required to pay for the security until the delivery date, these risks are in addition to the risks associated with the Fund’s other investments. If the Fund remains substantially fully invested at a time when when-issued, delayed delivery or forward commitment purchases are outstanding, the purchases may result in a form of leverage.

When the Fund has sold a security on a when-issued, delayed delivery or forward commitment basis, the Fund does not participate in future gains or losses with respect to the security. If the other party to a transaction fails to deliver or pay for the securities, the Fund could miss a favorable price or yield opportunity or could suffer a loss.

The Fund may dispose of or renegotiate a transaction after it is entered into, and may sell when-issued, delayed delivery or forward commitment securities before they are delivered, which may result in a capital gain or loss. There is no percentage limitation on the extent to which the Fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis.

Common stock generally takes the form of shares in a corporation. The value of a company’s stock may fall as a result of factors directly relating to that company, such as decisions made by its management or lower demand for the company’s products or services. A stock’s value also may fall because of factors affecting not just the company, but also companies in the same industry or in a number of different industries, such as increases in production costs. The value of a company’s stock also may be affected by changes in financial markets that are relatively unrelated to the company or its industry, such as changes in interest rates or currency exchange rates. In addition, a company’s stock generally pays dividends only after the company invests in its own business and makes required payments to holders of its bonds, other debt and preferred stock. For this reason,

the value of a company’s stock will usually react more strongly than its bonds, other debt and preferred stock to actual or perceived changes in the company’s financial condition or prospects. Stocks of smaller companies may be more vulnerable to adverse developments than those of larger companies. Stocks of companies that the portfolio managers believe are fast-growing may trade at a higher multiple of current earnings than other stocks. The value of such stocks may be more sensitive to changes in current or expected earnings than the values of other stocks.

The Fund may make short sales of securities (i) to offset potential declines in long positions in similar securities, (ii) to increase the flexibility of the Fund, (iii) for investment return, (iv) as part of a risk arbitrage strategy, and (v) as part of its overall portfolio management strategies involving the use of derivative instruments. A short sale is a transaction in which the Fund sells a security it does not own in anticipation that the market price of that security will decline or will underperform relative to other securities held in the Fund’s portfolio.

When the Fund makes a short sale, it must borrow the security sold short and deliver it to the broker-dealer through which it made the short sale as collateral for its obligation to deliver the security upon conclusion of the sale. The Fund may have to pay a fee to borrow particular securities or maintain an arrangement with a broker to borrow securities and would often be obligated to pay over any accrued interest and dividends on such borrowed securities.

If the price of the security sold short increases between the time of the short sale and the time that the Fund replaces the borrowed security, the Fund will incur a loss; conversely, if the price declines, the Fund will realize a capital gain. Any gain will be decreased, and any loss increased, by the transaction costs described above. The successful use of short selling may be adversely affected by imperfect correlation between movements in the price of the security sold short and the securities being hedged.

The Fund may invest pursuant to a risk arbitrage strategy to take advantage of a perceived relationship between the value of two securities. Frequently, a risk arbitrage strategy involves the short sale of a security.

To the extent the Fund engages in short sales, it will provide collateral to the broker-dealer and (except in the case of short sales “against the box”) will maintain additional asset coverage in the form of segregated or “earmarked” assets determined to be liquid by PIMCO in accordance with procedures approved by the Board of Trustees. A short sale is “against the box” to the extent that the Fund contemporaneously owns, or has the right to obtain at no added cost, securities identical to those sold short. The Fund will engage in short selling to the extent permitted by the federal securities laws and rules and interpretations thereunder. To the extent the Fund engages in short selling in foreign (non-U.S.) jurisdictions, the Fund will do so to the extent permitted by the laws and regulations of such jurisdiction.

The Fund may also engage in so-called “naked” short sales (i.e., short sales that are not “against the box”), in which case the Fund’s losses could theoretically be unlimited, in cases where the Fund is unable for whatever reason to close out its short position. The Fund has the flexibility to engage in short selling to the extent permitted by the 1940 Act and rules and interpretations thereunder.

The Fund may invest up to 20% of its total assets in illiquid securities. PIMCO may be subject to significant delays in disposing of illiquid securities, and other transaction costs that are higher than those for transactions in liquid securities may entail registration expenses and other transaction costs that are higher than those for transactions in liquid securities. The term “illiquid securities” for this purpose means any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. Depending on the circumstances, illiquid securities may be considered to include, among other things, certain purchased over-the-counter options and the assets used to cover certain written over-the-counter options, securities or other liquid assets being used as cover for such options, repurchase agreements with maturities in excess of seven days, certain loan participation interests, fixed time deposits which are not subject to prepayment or provide for withdrawal penalties upon prepayment (other than overnight deposits), securities that are subject to legal or contractual restrictions on resale (such as privately placed debt securities), and other securities which legally or in PIMCO’s opinion may be deemed illiquid (not including securities issued pursuant to Rule 144A under the 1933 Act), and certain commercial paper that PIMCO has determined to be liquid under procedures approved by the Board of Trustees).

The Fund may invest in securities that have not been registered for public sale, but that are eligible for purchase and sale pursuant to Rule 144A under the 1933 Act. Rule 144A permits certain qualified institutional buyers, such as the Fund, to trade in privately placed securities that have not been registered for sale under the 1933 Act. Rule 144A Securities may be deemed illiquid, although the Fund may determine that certain Rule 144A Securities are liquid in accordance with procedures adopted by the Board of Trustees.

To the extent consistent with its objective and strategy and permissible under the 1940 Act, the Fund may invest in securities of open- or closed-end investment companies, including exchange-traded funds (“ETFs”).

In general, under the 1940 Act, an investment company such as the Fund may not (i) own more than 3% of the outstanding voting securities of any one registered investment company, (ii) invest more than 5% of its total assets in the securities of any single registered investment company or (iii) invest more than 10% of its total assets in securities of other registered investment companies.

The Fund may invest in other investment companies to gain broad market or sector exposure, including during periods when it has large amounts of uninvested cash (such as the period shortly after the Fund receives the proceeds of the offering of its Common Shares) or when PIMCO believes share prices of other investment companies offer attractive values.

As a shareholder in an investment company, the Fund will bear its ratable share of that investment company’s expenses and would remain subject to payment of the Fund’s management fees and other expenses with respect to assets so invested. Common Shareholders would therefore be subject to duplicative expenses to the extent the Fund invests in other investment companies. In addition, the securities of other investment companies may also be leveraged and will therefore be subject to the same leverage risks described in the Prospectus and herein.

A private placement involves the sale of securities that have not been registered under the 1933 Act, or relevant provisions of applicable non-U.S. law, to certain institutional and qualified individual purchasers, such as the Fund. In addition to the general risks to which all securities are subject, securities received in a private placement generally are subject to strict restrictions on resale, and there may be no liquid secondary market or ready purchaser for such securities. Therefore, the Fund may be unable to dispose of such securities when it desires to do so, or at the most favorable time or price. Private placements may also raise valuation risks.

Operational Risk. An investment in the Fund, like any fund, can involve operational risks arising from factors such as processing errors, human errors, inadequate or failed internal or external processes, failures in systems and technology, changes in personnel and errors caused by third-party service providers. The occurrence of any of these failures, errors or breaches could result in a loss of information, regulatory scrutiny, reputational damage or other events, any of which could have a material adverse effect on the Fund. While the Fund seeks to minimize such events through controls and oversight, there may still be failures that could cause losses to the Fund.

Cybersecurity Risk. As the use of technology has become more prevalent in the course of business, the Fund has become potentially more susceptible to operational and informational security risks resulting from breaches in cyber security. A breach in cyber security refers to both intentional and unintentional cyber events that may, among other things, cause the Fund to lose proprietary information, suffer data corruption and/or destruction, lose operational capacity, result in the unauthorized release or other misuse of confidential information, or otherwise disrupt normal business operations. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems (e.g., through “hacking” or malicious software coding), but may also result from outside attacks such as denial-of-service attacks (i.e., efforts to make network services unavailable to intended users). In addition, cyber security breaches involving the Fund’s third party service providers (including but not limited to advisers, administrators, transfer agents, custodians, distributors and other third parties), trading counterparties or issuers in which the Fund invests can also subject the Fund to many of the same risks associated with direct cyber security breaches. Moreover, cyber security breaches involving trading counterparties or issuers in which the Fund invests could adversely impact such counterparties or issuers and cause the Fund’s investment to lose value. Cyber security failures or breaches may result in financial losses to the Fund and its shareholders. These failures or breaches may also result in disruptions to business operations, potentially resulting in financial losses; interference with the Fund’s ability to calculate its NAV, process shareholder transactions or otherwise transact business with shareholders; impediments to trading; violations of applicable privacy and other laws; regulatory fines; penalties; reputational damage; reimbursement or other compensation costs; additional compliance and cyber security risk management costs and other adverse consequences. In addition, substantial costs may be incurred in an attempt to prevent any cyber incidents in the future.

Like with operational risk in general, the Fund has established risk management systems and business continuity plans designed to reduce the risks associated with cyber security. However, there are inherent limitations in these plans and systems, including that certain risks may not have been identified, in large part because different or unknown threats may emerge in the future. As such, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers in which the Fund may invest, trading counterparties or third party service providers to the Fund. There is also a risk that cyber security breaches may not be detected. The Fund and its shareholders could be negatively impacted as a result.

The selling of the securities held by the Fund and reinvestment of the proceeds is known as “portfolio turnover.” PIMCO manages the Fund without regard generally to restrictions on portfolio turnover. Trading in fixed income securities does not generally involve the payment of brokerage commissions, but does involve indirect transaction costs. Trading in equity securities involves the payment of brokerage commissions, which are transaction costs paid by the Fund. The use of futures contracts may involve the payment of commissions to futures commission merchants. High portfolio turnover (e.g., greater than 100%) involves correspondingly greater expenses to the Fund, including brokerage commissions or dealer mark-ups and other transaction costs on the sale of securities and reinvestments in other securities. The higher the rate of portfolio turnover of the Fund, the higher these transaction costs borne by the Fund generally will be. Such sales may result in realization of taxable capital gains (including short-term capital gains which are taxed when distributed to shareholders who are individuals at ordinary income tax rates). See “Taxation.”

The portfolio turnover rate of the Fund is calculated by dividing (a) the lesser of purchases or sales of portfolio securities for the particular fiscal year by (b) the monthly average of the value of the portfolio securities owned by the Fund during the particular fiscal year. In calculating the rate of portfolio turnover, there is excluded from both (a) and (b) all derivatives and all securities, including options, whose maturities or expiration dates at the time of acquisition were one year or less. Proceeds from short sales and assets used to cover short positions undertaken are also excluded from both (a) and (b). For the fiscal year ended July 31, 2017, the Fund’s portfolio turnover rate was 39%. For the fiscal year ended July 31, 2016 the Fund’s portfolio turnover rate was 45%.

The Fund may invest in or acquire warrants to purchase equity or fixed income securities. Warrants are securities that are usually issued together with a debt security or preferred stock and that give the holder the right to buy a proportionate amount of common stock at a specific price. Warrants are freely transferable and are often traded on major exchanges. Warrants normally have a life that is measured in years and entitle the holder to buy common stock of a company at a price that is usually higher than the market price at the time the warrant is issued. Warrants may entail greater risks than certain other types of investments. Generally, warrants do not carry the right to receive dividends or exercise voting rights with respect to the underlying securities, and they do not represent any rights in the assets of the issuer. In addition, their value does not necessarily change with the value of the underlying securities, and they cease to have value if they are not exercised on or before their expiration date. If the market price of the underlying stock does not exceed the exercise price during the life of the warrant, the warrant will expire worthless. Warrants may increase the potential profit or loss to be realized from the investment as compared with investing the same amount in the underlying securities. Similarly, the percentage increase or decrease in the value of an equity security warrant may be greater than the percentage increase or decrease in the

value of the underlying common stock. Warrants may relate to the purchase of equity or debt securities. Debt obligations with warrants attached to purchase equity securities have many characteristics of convertible securities and their prices may, to some degree, reflect the performance of the underlying stock. Debt obligations also may be issued with warrants attached to purchase additional debt securities at the same coupon rate. A decline in interest rates would permit the Fund to sell the warrants at a profit. If interest rates rise, the warrants would generally expire with no value.

The Fund may from time to time use non-standard warrants, including low exercise price warrants or low exercise price options (“LEPOs”), to gain exposure to issuers in certain countries. LEPOs are different from standard warrants in that they do not give their holders the right to receive a security of the issuer upon exercise. Rather, LEPOs pay the holder the difference in price of the underlying security between the date the LEPO was purchased and the date it is sold. Additionally, LEPOs entail the same risks as other OTC derivatives, including the risks that the counterparty or issuer of the LEPO may not be able to fulfill its obligations, that the holder and counterparty or issuer may disagree as to the meaning or application of contractual terms, or that the instrument may not perform as expected. Furthermore, while LEPOs may be listed on an exchange, there is no guarantee that a liquid market will exist or that the counterparty or issuer of a LEPO will be willing to repurchase such instrument when the Fund wishes to sell it.

Subject to certain conditions described in the Prospectus and below, the Fund may make secured loans of its portfolio securities to brokers, dealers and other financial institutions amounting to no more than one-third of its total assets. The risks in lending portfolio securities, as with other extensions of credit, include possible delay in recovery of the securities or possible loss of rights in the collateral should the borrowers (which typically include broker-dealers and other financial services companies) fail financially. However, such loans will be made only to borrowers that are believed by PIMCO to be of satisfactory credit standing. Securities loans are made to broker-dealers pursuant to agreements requiring that loans be continuously secured by collateral consisting of U.S. Government securities, cash or cash equivalents (negotiable certificates of deposit, bankers’ acceptances or letters of credit) maintained on a daily mark-to-market basis in an amount at least equal at all times to the market value of the securities lent. The borrower pays to the Fund, as the lender, an amount equal to any dividends or interest received on the securities lent.

The Fund may invest only the cash collateral received in interest-bearing, short-term securities or receive a fee from the borrower. In the case of cash collateral, the Fund typically pays a rebate to the lender. Although voting rights or rights to consent with respect to the loaned securities pass to the borrower, the Fund, as the lender, retains the right to call the loans and obtain the return of the securities loaned at any time on reasonable notice, and it will do so in order that the securities may be voted by the Fund if the holders of such securities are asked to vote upon or consent to matters materially affecting the investment. The Fund may also call such loans in order to sell the securities involved. The Fund’s performance will continue to reflect changes in the value of the securities loaned and will also reflect the receipt of either interest, through investment of cash collateral by the Fund in permissible investments, or a fee, if the collateral is U.S. Government securities.

Generally, when the Fund holds bonds or other similar fixed income securities of an issuer, the Fund becomes a creditor of the issuer. As a creditor of an issuer, the Fund may be subject to challenges related to the securities that it holds, either in connection with the bankruptcy of the issuer or in connection with another action brought by other creditors of the issuer, shareholders of the issuer or the issuer itself (collectively, “restructuring transactions”). Although under no obligation to do so, PIMCO, as adviser to the Fund, may from time to time have an opportunity to consider, on behalf of the Fund and other similarly situated clients, negotiating or otherwise participating in the restructuring of the Fund’s portfolio investment or the issuer of such investment. PIMCO, in its judgment and discretion and based on the considerations deemed by PIMCO to be relevant, may believe that it is in the best interests of the Fund to negotiate or otherwise participate in a restructuring transaction. Accordingly, and subject to applicable procedures approved by the Board of Trustees, the Fund may from time to time participate on committees formed by creditors to negotiate with the management of financially troubled issuers of securities held by the Fund. Such participation may subject the Fund to expenses such as legal fees and may make the Fund an “insider” of the issuer for purposes of the federal securities laws, and therefore may restrict the Fund’s ability to trade in or acquire additional positions in a particular security when it might otherwise desire to do so. Participation by the Fund on such committees also may expose the Fund to potential liabilities under the federal bankruptcy laws or other laws governing the rights of creditors and debtors. Further, PIMCO has the general authority, subject to the above-mentioned procedures, to represent the Fund on creditors’ committees (or similar committees) or otherwise in connection with a restructuring transaction.

Upon PIMCO’s recommendation, for temporary defensive purposes and in order to keep the Fund’s cash fully invested, the Fund may invest up to 100% of its net assets in investment grade debt securities, including high quality, short-term debt instruments, credit-linked trust certificates and/or index futures contracts or similar derivative instruments. Such investments may prevent the Fund from achieving its investment objective.

The requirements for qualification as a regulated investment company under Subchapter M of the Code may limit the extent to which the Fund may invest in certain securities and transactions described above. In addition, the Fund’s utilization of certain investment instruments may alter the amount, timing and character of the Fund’s income, and, in turn, of the Fund’s distributions to its shareholders, relative to other means of achieving similar investment exposure. In certain circumstances, the Fund may be required to sell assets in order to meet regulated investment company distribution requirements even when investment considerations make such sales otherwise undesirable. For more information concerning these requirements and the taxation of the Fund’s investments, see “Taxation” below.

Except as described below, the Fund, as a fundamental policy, may not, without the approval of the holders of a majority of the outstanding Common Shares and any outstanding preferred shares of beneficial interest (including Preferred Shares) voting together as a single class, and of the holders of a majority of any outstanding preferred shares of beneficial interest (including Preferred Shares) voting as a separate class:

For purposes of the foregoing, “majority of the outstanding,” when used with respect to particular shares of the Fund (whether voting together as a single class or voting as separate classes), means (i) 67% or more of such shares present at a meeting, if the holders of more than 50% of such shares are present or represented by proxy, or (ii) more than 50% of such shares, whichever is less.

Unless otherwise indicated, all limitations applicable to the Fund’s investments (as stated above and elsewhere in this Statement of Additional Information) apply only at the time a transaction is entered into. Any subsequent change in a rating assigned by any rating service to a security (or, if unrated, deemed by PIMCO to be of comparable quality), or change in the percentage of the Fund’s assets invested in certain securities or other instruments, or change in the average maturity or duration of the Fund’s investment portfolio, resulting from market fluctuations or other changes in the Fund’s total assets, will not require the Fund to dispose of an investment until PIMCO determines that it is practicable to sell or close out the investment without undue market or tax consequences to the Fund. In the event that rating agencies assign different ratings to the same security, PIMCO will determine which rating it believes best reflects the security’s quality and risk at that time, which may be the higher of the several assigned ratings.

Under the Fund’s policy in paragraph (3) above in “Fundamental Investment Restrictions,” where the Fund purchases a loan or other security secured by real estate or interests therein, in the event of a subsequent default, foreclosure, or similar event, the Fund may take possession of and hold the underlying real estate in accordance with its rights under the initial security and subsequently sell or otherwise dispose of such real estate.

Under the 1940 Act, a “senior security” does not include any promissory note or evidence of indebtedness where such loan is for temporary purposes only and in an amount not exceeding 5% of the value of the total assets of the issuer at the time the loan is made. A loan is presumed to be for temporary purposes if it is repaid within sixty days and is not extended or renewed.

For purposes of applying the terms of the Fund’s policy in paragraph (1) above (the “industry concentration policy”), the Fund would be deemed to “concentrate” in a particular industry if it invests more than 25% of its net assets in that industry. For purposes of the industry concentration policy, PIMCO will, on behalf of the Fund, make reasonable determinations as to the appropriate industry classification to assign to each security or instrument in which the Fund invests. The definition of what constitutes a particular “industry” is an evolving one, particularly for industries or sectors within industries that are new or are undergoing rapid development. Some securities could reasonably fall within more than one industry category. The Fund’s industry concentration policy does not preclude it from focusing investments in issuers in a group of related industrial sectors (such as different types of utilities). For purposes of the industry concentration policy, a foreign government is considered to be an industry, although currency positions are not considered to be an investment in a foreign government for these purposes. Mortgage-related or asset-backed securities that are issued or guaranteed as to principal or interest by the U.S. Government or its agencies or instrumentalities are not subject to the Fund’s industry concentration policy, by virtue of the exclusion from that test available to all U.S. Government securities. Tax-exempt municipal bonds issued by states, municipalities and other political subdivisions, agencies, authorities and instrumentalities of states and multi-state agencies and authorities are not subject to the Fund’s industry concentration policy. To the extent that an underlying investment company in which the Fund invests has adopted a policy to concentrate its investments in a particular industry, the Fund will, to the extent applicable, take such underlying investment company’s concentration policy into consideration for purposes of the Fund’s own industry concentration policy.

The Fund may not change its policy to invest at least 80% of its total assets in a combination of corporate debt obligations of varying maturities, other corporate income-producing securities, and income-producing securities of non-corporate issuers unless it provides shareholders with at least 60 days’ written notice of such change.

To the extent the Fund covers its commitment under a reverse repurchase agreement, credit default swap or other derivative instrument by the segregation of assets determined by PIMCO to be liquid in accordance with procedures adopted by the Trustees, equal in value to the amount of the Fund’s commitment, such instrument will not be considered a “senior security” for purposes of the asset coverage requirements otherwise applicable to borrowings by the Fund or the Fund’s issuance of Preferred Shares.

The Fund interprets its policies with respect to borrowing and lending to permit such activities as may be lawful for the Fund, to the full extent permitted by the 1940 Act or by exemption from the provisions therefrom pursuant to exemptive order of the SEC.

It is a condition of the issuance of the Preferred Shares that they be issued with a credit quality rating of “Aaa” from Moody’s. In order to obtain and maintain the required rating, the Fund will be required to comply with investment quality, diversification and other guidelines established by Moody’s. Such guidelines will likely be more restrictive than the restrictions set forth above. The Fund does not anticipate that such guidelines would have a material adverse effect on the holders of the Common Shares (“Common Shareholders”) or its ability to achieve its investment objective. Moody’s receives fees in connection with their ratings issuances.

For purposes of its investment policies and restrictions, with the exception of the Fund’s policy to invest, under normal circumstances, at least 80% of its net assets (plus any borrowings for investment purposes) in a portfolio of debt instruments of varying maturities (the “80% policy”), the Fund may value derivative instruments at market value, notional value or full exposure value (i.e., the sum of the notional amount for the contract plus the market value). For example, the Fund may value credit default swaps at full exposure value for purposes of the Fund’s credit quality guidelines because such value in general better reflects the Fund’s actual economic exposure during the term of the credit default swap agreement. As a result, the Fund may, at times, have notional exposure to an asset class (before netting) that is greater or lesser than the stated limit or restriction noted in the Fund’s prospectus. In this context, both the notional amount and the market value may be positive or negative depending on whether the Fund is selling or buying protection through the credit default swap. For purposes of the Fund’s 80% policy, the Fund values its derivative instruments based on their market value. The manner in which certain securities or other instruments are valued by the Fund for purposes of applying investment policies and restrictions may differ from the manner in which those investments are valued by other types of investors.

From time to time, the Fund may voluntarily participate in actions (for example, rights offerings, conversion privileges, exchange offers, credit event settlements, etc.) where the issuer or counterparty offers securities or instruments to holders or counterparties, such as the Fund, and the acquisition is determined to be beneficial to Fund shareholders (“Voluntary Action”). Notwithstanding any percentage investment limitation listed under this “Investment Restrictions” section or any percentage investment limitation of the 1940 Act or rules thereunder, if the Fund has

the opportunity to acquire a permitted security or instrument through a Voluntary Action, and the Fund will exceed a percentage investment limitation following the acquisition, it will not constitute a violation if, prior to the receipt of the securities or instruments and after announcement of the offering, the Fund sells an offsetting amount of assets that are subject to the investment limitation in question at least equal to the value of the securities or instruments to be acquired.

Unless otherwise indicated, all percentage limitations on Fund investments (as stated throughout this Statement of Additional Information or in the Prospectus) that are not: (i) specifically included in this “Investment Restrictions” section; or (ii) imposed by the 1940 Act, rules thereunder, the Code or related regulations (the “Elective Investment Restrictions”), will apply only at the time of investment unless the acquisition is a Voluntary Action. The percentage limitations and absolute prohibitions with respect to Elective Investment Restrictions are not applicable to the Fund’s acquisition of securities or instruments through a Voluntary Action.

The Fund may engage in roll-timing strategies where the Fund seeks to extend the expiration or maturity of a position, such as a forward contract, futures contract or to-be-announced (“TBA”) transaction, on an underlying asset by closing out the position before expiration and contemporaneously opening a new position with respect to the same underlying asset that has substantially similar terms except for a later expiration date. Such “rolls” enable the Fund to maintain continuous investment exposure to an underlying asset beyond the expiration of the initial position without delivery of the underlying asset. Similarly, as certain standardized swap agreements transition from over-the-counter trading to mandatory exchange-trading and clearing due to the implementation of Dodd-Frank Act regulatory requirements, the Fund may “roll” an existing over-the-counter swap agreement by closing out the position before expiration and contemporaneously entering into a new exchange-traded and cleared swap agreement on the same underlying asset with substantially similar terms except for a later expiration date. These types of new positions opened contemporaneous with the closing of an existing position on the same underlying asset with substantially similar terms are collectively referred to as “Roll Transactions.” Elective Investment Restrictions (defined in the preceding paragraph), which normally apply at the time of investment, do not apply to Roll Transactions (although Elective Investment Restrictions will apply to the Fund’s entry into the initial position). In addition and notwithstanding the foregoing, for purposes of this policy, those Non-Fundamental Investment Restrictions that are considered Elective Investment Restrictions for purposes of the policy on Voluntary Actions (described in the preceding paragraph) are also Elective Investment Restrictions for purposes of this policy on Roll Transactions. The Fund will test for compliance with Elective Investment Restrictions at the time of the Fund’s initial entry into a position, but the percentage limitations and absolute prohibitions set forth in the Elective Investment Restrictions are not applicable to the Fund’s subsequent acquisition of securities or instruments through a Roll Transaction.

The business of the Fund is managed under the direction of the Fund’s Board of Trustees (the “Board”). Subject to the provisions of the Fund’s Amended and Restated Agreement and Declaration of Trust, as may be amended from time to time (the “Declaration”) its Bylaws, as may be amended from time to time (the “Bylaws”) and Massachusetts law, the Trustees have all powers necessary and convenient to carry out their responsibilities, including the election and removal of the Fund’s officers.

Board Leadership Structure — The Board consists of eight Trustees, six of whom are not “interested persons” (within the meaning of Section 2(a)(19) of the 1940 Act) of the Fund or of the Investment Manager (the “Independent Trustees”), which represents 75% of the Trustees that are Independent Trustees. An Independent Trustee serves as Chairman of the Board and is selected by a vote of the majority of the Independent Trustees. The Chairman of the Trustees presides at meetings of the Board and acts as a liaison with service providers, officers, attorneys and other Trustees generally between meetings, and performs such other functions as may be requested by the Board from time to time.

The Board meets regularly four times each year to discuss and consider matters concerning the Fund, and also holds special meetings to address matters arising between regular meetings. The Independent Trustees regularly meet outside the presence of management and are advised by independent legal counsel. Regular meetings generally take place in-person; other meetings may take place in-person or by telephone.

The Board has established six standing Committees to facilitate the Trustees’ oversight of the management of the Fund: the Audit Oversight Committee, the Nominating Committee, the Valuation Oversight Committee, the Compensation Committee, the Contracts Committee and the Performance Committee. The functions and role of each Committee are described below under “Committees of the Board of Trustees.” The membership of each Committee consists of all of the Independent Trustees, which the Board believes allows them to participate in the full range of the Board’s oversight duties. In addition, the Performance Committee consists of all of the Trustees.

The Board reviews its leadership structure periodically and has determined that this leadership structure, including an Independent Chairman, a supermajority of Independent Trustees and Committee membership limited to Independent Trustees (with the exception of the Performance Committee), is appropriate in light of the characteristics and circumstances of the Fund. In reaching this conclusion, the Board considered, among other things, the predominant role of the Investment Manager in the day-to-day management of Fund affairs, the extent to which the work of the Board is conducted through the Committees, the number of funds overseen by the Board that are advised by the Investment Manager or have an investment adviser that is an affiliated person of the Investment Manager (the “Fund Complex”), the variety of asset classes those funds include, the assets of the Fund and the other funds overseen by the Board in the Fund Complex and the management and other service arrangements of the Fund and such other funds. The Board also believes that its structure, including the presence of two Trustees who are executives with the Investment Manager or Investment Manager-affiliated entities, facilitates an efficient flow of information concerning the management of the Fund to the Independent Trustees.

Risk Oversight — The Fund has retained the Investment Manager to provide investment advisory services and administrative services. Accordingly, the Investment Manager is immediately responsible for the management of risks that may arise from Fund investments and operations. Some employees of the Investment Manager serve as the Fund’s officers, including the Fund’s principal executive officer and principal financial and accounting officer, chief compliance officer and chief legal officer. The Investment Manager and the Fund’s other service providers have adopted policies, processes, and procedures to identify, assess and manage different types of risks associated with the Fund’s activities. The Board oversees the performance of these functions by the Investment Manager and the Fund’s other service providers, both directly and through the

Committee structure it has established. The Board receives from the Investment Manager a wide range of reports, both on a regular and as-needed basis, relating to the Fund’s activities and to the actual and potential risks of the Fund. These include reports on investment and market risks, custody and valuation of Fund assets, compliance with applicable laws, and the Fund’s financial accounting and reporting. In addition, the Board meets periodically with the portfolio managers of the Fund or their delegates to receive reports regarding the portfolio management of the Fund and its performance, including its investment risks. In the course of these meetings and discussions with the Investment Manager, the Board has emphasized to the Investment Manager the importance of maintaining vigorous risk management programs and procedures.

In addition, the Board has appointed a Chief Compliance Officer (“CCO”). The CCO oversees the development of compliance policies and procedures that are reasonably designed to minimize the risk of violations of the federal securities laws (“Compliance Policies”). The CCO reports directly to the Independent Trustees, interacts with individuals within the Investment Manager’s organization and provides presentations to the Board at its quarterly meetings and an annual report on the application of the Compliance Policies. The Board periodically discusses relevant risks affecting the Fund with the CCO at these meetings. The Board has approved the Compliance Policies and reviews the CCO’s reports. Further, the Board annually reviews the sufficiency of the Compliance Policies, as well as the appointment and compensation of the CCO.

The Board recognizes that the reports it receives concerning risk management matters are, by their nature, typically summaries of the relevant information. Moreover, the Board recognizes that not all risks that may affect the Fund can be identified in advance; that it may not be practical or cost-effective to eliminate or mitigate certain risks; that it may be necessary to bear certain risks (such as investment-related risks) in seeking to achieve the Fund’s investment objective; and that the processes, procedures and controls employed to address certain risks may be limited in their effectiveness.

The Trustees and officers of the Fund, their year of birth, the position they hold with the Fund, their term of office and length of time served, a description of their principal occupations during the past five years, the number of portfolios in the Fund Complex that the Trustee oversees and any other public company directorships held by the Trustee are listed in the two tables immediately following. Except as shown, each Trustee’s and officer’s principal occupation and business experience for the last five years have been with the employer(s) indicated, although in some cases the Trustee may have held different positions with such employer(s).

* “Independent Trustees” are those Trustees who are not “interested persons” (as defined in Section 2(a)(19) of the 1940 Act).

** Unless otherwise indicated, the business address of the persons listed above is c/o Pacific Investment Management Company LLC, 1633 Broadway, New York, New York 10019.

*** The term “Fund Complex” as used herein includes the Fund and the following registered investment companies: PIMCO Municipal Income Fund, PIMCO California Municipal Income Fund, PIMCO New York Municipal Income Fund, PIMCO Municipal Income Fund II, PIMCO California Municipal Income Fund II, PIMCO New York Municipal Income Fund II, PIMCO Municipal Income Fund III, PIMCO California Municipal Income Fund III, PIMCO New York Municipal Income Fund III, PIMCO Corporate & Income Strategy Fund, PIMCO Income Opportunity Fund, PCM Fund, Inc., PIMCO Dynamic Credit and Mortgage Income Fund, PIMCO Dynamic Income Fund, PIMCO High Income Fund, PIMCO Income Strategy Fund, PIMCO Income Strategy Fund II, PIMCO Global StocksPLUS^®& Income Fund, PIMCO Strategic Income Fund, Inc., each series of PIMCO Managed Accounts Trust, PIMCO Flexible Credit Income Fund, AllianzGI Diversified Income & Convertible Fund, AllianzGI Convertible & Income 2024 Target Term Fund, AllianzGI Convertible & Income Fund, AllianzGI Convertible & Income Fund II, AllianzGI NFJ Dividend, Interest & Premium Strategy Fund, AllianzGI Equity & Convertible Income Fund, AllianzGI Convertible & Income 2024 Target Term Fund, each series of Allianz Funds, Allianz Funds Multi-Strategy Trust, AllianzGI Institutional Multi-Series Trust and Premier Multi-Series VIT.

**** Mr. Dawson is an “interested person” of the Fund, as defined in Section 2(a)(19) of the 1940 Act, due to his affiliation with PIMCO and its affiliates.

***** Mr. Maney is an “interested person” of the Fund, as defined in Section 2(a)(19) of the 1940 Act, due to his affiliation with Allianz Asset Management of America, L.P and its affiliates.

In accordance with the Fund’s staggered board (see “Anti-Takeover and Other Provisions in the Declaration of Trust”), the Common Shareholders of the Fund elect Trustees to fill the vacancies of Trustees whose terms expire at each annual meeting of Common Shareholders. So long as any Preferred Shares or any other preferred shares of beneficial interest are outstanding Preferred Shareholders and holders of any other preferred shares outstanding, voting as a separate class, will elect two Trustees and the remaining Trustees will be elected by Common Shareholders and Preferred Shareholders and holders of any other preferred shares outstanding, voting together as a single class. Preferred Shareholders and holders of any other preferred shares outstanding are entitled to elect a majority of the Fund’s Trustees under certain circumstances.

Each of the Fund’s executive officers is an “interested person” of the Fund (as defined in Section 2(a)(19) of the 1940 Act) as a result of his or her position(s) set forth in the table above.

Trustee Qualifications. The Board has determined that each Trustee is qualified to serve as such based on several factors (none of which alone is decisive). Each Trustee has served in such role for several years. Accordingly, each Trustee is knowledgeable about the Fund’s business and service provider arrangements, in part because he or she has also served for several years as trustee or director to a number of other investment companies advised by the Investment Manager and its affiliates with similar arrangements to that of the Fund. Among the factors the Board considered when concluding that an individual is qualified to serve on the Board were the following: (i) the individual’s business and professional experience and accomplishments; (ii) the individual’s ability to work effectively with other members of the Board; (iii) the individual’s prior experience, if any, serving on the boards of public companies (including, where relevant, other investment companies) and other complex enterprises and organizations; and (iv) how the individual’s skills, experiences and attributes would contribute to an appropriate mix of relevant skills and experience on the Board.

In respect of each current Trustee, the individual’s substantial professional accomplishments and prior experience, including, in some cases, in fields related to the operations of the Fund, were a significant factor in the determination by the Board that the individual is qualified to serve as a Trustee of the Fund. The following is a summary of various qualifications, experiences and skills of each Trustee (in addition to business experience during the past five years set forth in the table above) that contributed to the Board’s conclusion that an individual is qualified to serve on the Board. References to qualifications, experiences and skills are not intended to hold out the Board or individual Trustees as having any special expertise or experience, and shall not impose any greater responsibility or liability on any such person or on the Board by reason thereof.

Hans W. Kertess — Mr. Kertess has substantial executive experience in the investment management industry. He is the president of a financial advisory company, H. Kertess & Co. and a Senior Adviser of Royal Bank of Canada Capital Markets, and formerly served as a Managing Director of Royal Bank of Canada Capital Markets. He has significant expertise in the investment banking industry.

Craig A. Dawson — Mr. Dawson has substantial executive experience in the investment management industry. Mr. Dawson is a Managing Director and Head of PIMCO Europe, Middle East and Africa. In that role he is in charge of guiding PIMCO’s business initiatives in Europe, the Middle East and Africa. Prior to taking on this position, Mr. Dawson was PIMCO’s Head of Strategic Business Management. Mr. Dawson also serves as a Director of a number of PIMCO’s European investment vehicles and affiliates. Because of his familiarity with PIMCO and its affiliates, Mr. Dawson serves as an important information resource for the Independent Trustees and as a facilitator of communication with PIMCO.

Deborah A. DeCotis — Ms. DeCotis has substantial senior executive experience in the investment banking industry, having served as a Managing Director for Morgan Stanley. She has extensive board experience and experience in oversight of investment management functions through her experience as a former Director of the Helena Rubenstein Foundation, Stanford Graduate School of Business and Armor Holdings.

Bradford K. Gallagher — Mr. Gallagher has substantial executive and board experience in the financial services and investment management industries. He has served as director to several other investment companies. Having served on the Operating Committee of Fidelity Investments and as a Managing Director and President of Fidelity Investments Institutional Services Company, he provides the Fund with significant asset management industry expertise. He also brings significant securities industry experience, having served as a developer and founder of several enterprises and private investment vehicles.

James A. Jacobson — Mr. Jacobson has substantial executive and board experience in the financial services industry. He served for more than 15 years as a senior executive at a New York Stock Exchange (the “NYSE”) specialist firm. He has also served on the NYSE Board of Directors, including terms as Vice Chair. As such, he provides significant expertise on matters relating to portfolio brokerage and trade execution. He also provides the Fund with significant financial expertise, serves as the Audit Oversight Committee’s Chair and has been determined by the Board to be an “audit committee financial expert.”

John C. Maney — Mr. Maney has substantial executive and board experience in the investment management industry. He has served in a variety of senior-level positions with investment advisory firms affiliated with the Investment Manager. Because of his familiarity with the Investment Manager and affiliated entities, he serves as an important information resource for the Independent Trustees and as a facilitator of communication with Allianz Asset Management of America L.P., PIMCO’s U.S. parent company.

William B. Ogden, IV — Mr. Ogden has substantial senior executive experience in the investment banking industry. He served as Managing Director at Citigroup, where he established and led the firm’s efforts to raise capital for, and provide mergers and acquisition advisory services to, asset managers and investment advisers. He also has significant expertise with fund products through his senior-level responsibility for originating and underwriting a broad variety of such products.

Alan Rappaport — Mr. Rappaport has substantial senior executive experience in the financial services industry. He formerly served as Chairman and President of the Private Bank of Bank of America and as Vice Chairman of U.S. Trust. He is currently an Advisory Director of an investment firm.

Audit Oversight Committee. The Board has established an Audit Oversight Committee, currently consisting of Messrs. Gallagher, Jacobson, Kertess, Ogden, Rappaport and Ms. DeCotis, each of whom is an Independent Trustee. Mr. Jacobson is the current Chair of the Fund’s Audit Oversight Committee.

The Audit Oversight Committee provides oversight with respect to the internal and external accounting and auditing procedures of the Fund and, among other things, determines the selection of an independent registered public accounting firm for the Fund and considers the scope of the audit, approves all audit and permitted non-audit services proposed to be performed by those auditors on behalf of the Fund and approves non-audit services to be performed by the auditors for

certain affiliates, including PIMCO and entities in a control relationship with PIMCO that provide services to the Fund where the engagement relates directly to the operations and financial reporting of the Fund. The Audit Oversight Committee considers the possible effect of those services on the independence of the Fund’s independent registered public accounting firm. During the fiscal year ended July 31, 2017 the Audit Oversight Committee met six times.

Nominating Committee. The Board has established a Nominating Committee composed solely of Independent Trustees, currently consisting of Messrs. Gallagher, Jacobson, Kertess, Ogden, Rappaport and Ms. DeCotis. The Nominating Committee is responsible for reviewing and recommending qualified candidates to the Board in the event that a position is vacated or created or when Trustees are to be re-elected. During the fiscal year ended July 31, 2017 the Nominating Committee met one time.

Qualifications, Evaluation and Identification of Trustee Nominees. The Nominating Committee of the Fund requires that Trustee candidates have a college degree or equivalent business experience. When evaluating candidates, the Nominating Committee may take into account a wide variety of factors including, but not limited to: (i) availability and commitment of a candidate to attend meetings and perform his or her responsibilities on the Board, (ii) relevant industry and related experience, (iii) educational background, (iv) ability, judgment and expertise and (v) overall diversity of the Board’s composition. The process of identifying nominees involves the consideration of candidates recommended by one or more of the following sources: (i) the Fund’s current Trustees, (ii) the Fund’s officers, (iii) the Fund’s investment adviser, (iv) the Fund’s shareholders and (v) any other source the Committee deems to be appropriate. The Nominating Committee may, but is not required to, retain a third-party search firm at the Fund’s expense to identify potential candidates.

Consideration of Candidates Recommended by Stockholders. The Nominating Committee will review and consider nominees recommended by shareholders to serve as Trustees, provided that the recommending shareholder follows the “Procedures for Shareholders to Submit Nominee Candidates”, which are set forth as Appendix A to the Fund’s Nominating Committee Charter and attached as Appendix A to this Statement of Additional Information. Among other requirements, these procedures provide that the recommending shareholder must submit any recommendation in writing to the Fund, to the attention of the Fund’s Secretary, at the address of the principal executive offices of the Fund and that such submission must be received at such offices not less than 45 days nor more than 75 days prior to the date of the Board or shareholder meeting at which the nominee would be elected. Because the Fund does not hold annual or other regular meetings of shareholders for the purpose of electing Trustees, the Committee will accept shareholder recommendations on a continuous basis. Any recommendation must include certain biographical and other information regarding the candidate and the recommending shareholder, and must include a written and signed consent of the candidate to be named as a nominee and to serve as a Trustee if elected. The foregoing description of the requirements is only a summary. Please refer to Appendix A to the Nominating Committee Charter, which is attached to this Statement of Additional Information as Appendix A.

The Nominating Committee has full discretion to reject nominees recommended by shareholders, and there is no assurance that any such person properly recommended and considered by the Committee will be nominated for election to the Board of Trustees.

Diversity. The Nominating Committee takes diversity of a particular nominee and overall diversity of the Board into account when considering and evaluating nominees for Trustee. While the Committee has not adopted a particular definition of diversity, when considering a nominee’s and the Board’s diversity, the Committee generally considers the manner in which each nominee’s professional experience, education, expertise in matters that are relevant to the oversight of the Fund (e.g., investment management, distribution, accounting, trading, compliance, legal), general leadership experience, and life experience are complementary and, as a whole, contribute to the ability of the Board to oversee the Fund.

Valuation Oversight Committee. The Board has established a Valuation Oversight Committee, which currently consists of currently consisting of Messrs. Gallagher, Jacobson, Kertess, Ogden and Rappaport and Ms. DeCotis. Mr. Ogden is the Chair of the Valuation Oversight Committee. The Valuation Oversight Committee has been delegated responsibility by the Board for overseeing determination of the fair value of the Fund’s portfolio securities and other assets on behalf of the Board in accordance with the Fund’s valuation procedures. The Valuation Oversight Committee reviews and approves procedures for the fair valuation of the Fund’s portfolio securities and periodically reviews information from PIMCO regarding fair value determinations made pursuant to Board-approved procedures, and makes related recommendations to the full Board and assists the full Board in resolving particular fair valuation and other valuation matters. In certain circumstances as specified in the Fund’s valuation policies, the Valuation Oversight Committee may also determine the fair value of portfolio holdings after consideration of all relevant factors, which determinations shall be reported to the full Board. During the fiscal year ended July 31, 2017 the Valuation Oversight Committee met three times.

Compensation Committee. The Board has established a Compensation Committee, which currently consists of Messrs. Gallagher, Jacobson, Kertess, Ogden, Rappaport and Ms. DeCotis. The Compensation Committee meets as the Board deems necessary to review and make recommendations regarding compensation payable to the Trustees who are not directors, officers, partners or employees of PIMCO or any entity controlling, controlled by or under common control with PIMCO. During the fiscal year ended July 31, 2017 the Compensation Committee met one time.

Contracts Committee. The Board of the Fund has established a Contracts Committee currently consisting of Messrs. Gallagher, Jacobson, Kertess, Ogden, Rappaport and Ms. DeCotis. Ms. DeCotis is the Chair of the Fund’s Contracts Committee. The Contracts Committee meets as the Board deems necessary to review the performance of, and the reasonableness of the fees paid to, as applicable, the Fund’s investment adviser(s) and any sub-adviser(s), administrators(s) and principal underwriters(s) and to make recommendations to the Board regarding the approval and continuance of the Fund’s contractual arrangements for investment advisory, sub-advisory, administrative and distribution services, as applicable. During the fiscal year ended July 31, 2017 the Contracts Committee met two times.

Performance Committee. The Board has established a Performance Committee, which consists of Messrs. Gallagher, Jacobson, Kertess, Ogden, Rappaport, Maney and Dawson and Ms. DeCotis. Mr. Rappaport is the Chair of the Performance Committee. The Performance Committee’s responsibilities include reviewing the performance of the Fund and any changes in investment philosophy, approach and personnel of the Investment Manager. The Performance Committee did not meet during the fiscal year ended July 31, 2017.

For each Trustee, the following table discloses the dollar range of equity securities in the Fund beneficially owned by the Trustee and, on an aggregate basis, in any registered investment companies overseen by the Trustee within the Fund’s family of investment companies as of December 31, 2017:

* The term “Family of Investment Companies” as used herein includes the Fund and the following registered investment companies: PIMCO Municipal Income Fund, PIMCO California Municipal Income Fund, PIMCO New York Municipal Income Fund, PIMCO Municipal Income Fund II, PIMCO California Municipal Income Fund II, PIMCO New York Municipal Income Fund II, PIMCO Municipal Income Fund III, PIMCO California Municipal Income Fund III, PIMCO New York Municipal Income Fund III, PIMCO Corporate & Income Strategy Fund, PIMCO Income Opportunity Fund, PCM Fund, Inc., PIMCO Dynamic Credit and Mortgage Income Fund, PIMCO Dynamic Income Fund, PIMCO High Income Fund, PIMCO Income Strategy Fund, PIMCO Income Strategy Fund II, PIMCO Global StocksPLUS^®& Income Fund, PIMCO Strategic Income Fund, Inc. and PIMCO Flexible Credit Income Fund, and each series of PIMCO Managed Accounts Trust.

To the Fund’s knowledge, the following table provides information regarding each class of securities owned beneficially in an investment adviser or principal underwriter of the Fund, or a person (other than a registered investment company) directly or indirectly controlling, controlled by, or under common control with an investment adviser or principal underwriter of the Fund as of December 31, 2017 by Independent Trustees and their immediate family members:

As of June 1, 2018, the Fund’s officers and Trustees as a group owned less than 1% of the outstanding Common Shares.

As of June 1, 2018, to the knowledge of the Fund, the following entities owned beneficially or of record the number of shares of the noted class as set forth below, representing the indicated percentage of such class as of such date. To the knowledge of the Fund, no other person owned of record or beneficially 5% or more of any class of the Fund’s outstanding equity securities on such date.

Each of the Independent Trustees also serves as a trustee of PIMCO Municipal Income Fund, PIMCO California Municipal Income Fund, PIMCO New York Municipal Income Fund, PIMCO Municipal Income Fund II, PIMCO California Municipal Income Fund II, PIMCO New York Municipal Income Fund II, PIMCO Municipal Income Fund III, PIMCO California Municipal Income Fund III, PIMCO New York Municipal Income Fund III, PIMCO

Corporate & Income Strategy Fund, PIMCO High Income Fund, PIMCO Dynamic Income Fund, PIMCO Income Opportunity Fund, PIMCO Income Strategy Fund, PIMCO Income Strategy Fund II, PIMCO Global StocksPLUS^® & Income Fund, PCM Fund, Inc., PIMCO Strategic Income Fund, Inc., and PIMCO Dynamic Credit and Mortgage Income Fund, each a closed-end fund for which the Investment Manager serves as investment manager (together, the “PIMCO Closed-End Funds”), PIMCO Flexible Credit Income Fund and PIMCO Flexible Municipal Income Fund, each a closed-end management investment company that is operated as an “interval fund” for which PIMCO serves as investment manager (the “PIMCO-Interval Funds”), and PIMCO Managed Accounts Trust, an open-end management investment company with multiple series for which PIMCO serves as investment adviser and administrator (the “Trust” and, together with the Fund, the PIMCO Closed-End Funds, and the PIMCO Interval Funds, the “PIMCO-Managed Funds”).

In addition, each of the Independent Trustees also serves as a trustee of AllianzGI Convertible & Income Fund, AllianzGI Convertible & Income Fund II, AllianzGI NFJ Dividend, Interest & Premium Strategy Fund, AllianzGI Equity & Convertible Income Fund, AllianzGI Diversified Income & Convertible Fund, AllianzGI Convertible & Income 2024 Target Term Fund, Allianz Funds, Allianz Funds Multi-Strategy Trust, AllianzGI Institutional Multi-Series Trust and Premier Multi-Series VIT, (together, the “Allianz-Managed Funds”), for which Allianz Global Investors U.S. LLC, an affiliate of PIMCO, serves as investment manager. The Independent Trustees receive separate compensation from the Allianz Managed Funds in addition to amounts received for service on the Boards of the PIMCO-Managed Funds.

Each of the PIMCO-Managed Funds holds joint meetings of their Boards of Trustees whenever possible. Each Independent Trustee receives annual compensation of $225,000 for his or her service on the Boards of the PIMCO-Managed Funds, payable quarterly. The Independent Chairman of the Boards receives an additional $75,000 per year, payable quarterly. The Audit Oversight Committee Chairman receives an additional $50,000 annually, payable quarterly. Trustees are also reimbursed for meeting-related expenses.

Each Trustee’s compensation for his or her service as a Trustee on the Boards of the PIMCO-Managed Funds and other costs in connection with joint meetings of such Funds are allocated among the PIMCO-Managed Funds, as applicable, on the basis of fixed percentages as among the Fund the Trust, PFLEX and the PIMCO Closed-End Funds. Trustee compensation and other costs are then further allocated pro rata among the individual funds within each grouping based on each such fund’s relative net assets.

The Fund has no employees. The Fund’s officers, Mr. Dawson and Mr. Maney, are compensated by PIMCO or its affiliates, as applicable.

The Trustees do not receive any pension or retirement benefits from the Fund or the Fund Complex (see below).

The following table provides information concerning the compensation paid to the Trustees by the Fund for the fiscal year ended July 31, 2017. For the calendar year ended December 31, 2017, the Trustees received the compensation set forth in the table below for serving as Trustees of the Fund and other funds in the same “Fund Complex” as the Fund. Each officer and each Trustee who is a director, officer, partner, member or employee of the Investment Manager, or of any entity controlling, controlled by or under common control with the Investment Manager, including any Interested Trustee, serves without any compensation from the Fund.

* In addition to the PIMCO-Managed Funds, which are advised by the Investment Manager, during the Fund’s most recently completed calendar year, all of the Trustees (other than Messrs. Dawson and Maney) served as trustees of the Allianz-Managed Funds, which are managed by Allianz Global Investors U.S. LLC. The Allianz-Managed Funds and the PIMCO-Managed Funds are considered to be in the same “Fund Complex.” Ms. DeCotis and Messrs. Kertess, Gallagher, Jacobson, Ogden and Rappaport currently serve as trustee or director of 93 funds in the Fund Complex. Mr. Maney and Mr. Dawson currently serve as trustee or director of 26 funds in the Fund Complex. For the calendar year ended December 31, 2017, amounts received by the Trustees from PIMCO-Managed Funds were: for Mr. Kertess, $300,000; for Mr. Jacobson, $275,000; for each of Messrs. Gallagher, Ogden, and Rappaport and Ms. DeCotis, $225,000. These amounts are included in the Fund Complex totals in the table above.

** Messrs. Dawson and Maney are interested Persons of the Fund and do not receive compensation from the Fund for their services as Trustees.

The Fund and PIMCO have each adopted a code of ethics under Rule 17j-1 of the 1940 Act. These codes permit personnel subject to the codes to invest in securities, including securities that may be purchased or held by the Fund. The codes of ethics can be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling the SEC at 1-202-551-8090. The codes are also available on the EDGAR Database on the SEC’s Internet site at http://www.sec.gov, and copies may be obtained, after paying a duplicating fee, by electronic request at the following email address: publicinfo@sec.gov, or by writing the SEC’s Public Reference Section, Washington, DC, 20549-0102.

PIMCO, a Delaware limited liability company, serves as investment manager to the Fund pursuant to an investment management agreement (the “Investment Management Agreement”) between PIMCO and the Fund. PIMCO is located at 650 Newport Center Drive, Newport Beach, California 92660. As of March 31, 2018, PIMCO had assets under management of approximately $1.77 trillion. As of March 31, 2018, PIMCO had third-party assets under management of approximately $1.35 trillion.

PIMCO is a majority owned subsidiary of Allianz Asset Management of America L.P. (“Allianz Asset Management”) with minority interests held by Allianz Asset Management of America LLC, and Allianz Asset Management U.S. Holding II LLC, each, a Delaware limited liability company and by certain current and former officers of PIMCO. Allianz Asset Management was organized as a limited partnership under Delaware law in 1987. Through various holding company structures, Allianz Asset Management is majority owned by Allianz SE. Allianz SE is a European based, multinational insurance and financial services holding company and a publicly traded German company.

The general partner of Allianz Asset Management has substantially delegated its management and control of Allianz Asset Management to a Management Board. The Management Board of Allianz Asset Management is comprised of John C. Maney.

As of the date of this Statement of Additional Information, there are no significant institutional shareholders of Allianz SE. Absent an SEC exemption or other regulatory relief, the Fund generally is precluded from effecting principal transactions with brokers that are deemed to be affiliated persons of the Fund or PIMCO, and the Fund’s ability to purchase securities being underwritten by an affiliated broker or a syndicate including an affiliated broker is subject to restrictions. Similarly, the Fund’s ability to utilize the affiliated brokers for agency transactions is subject to the restrictions of Rule 17e-1 under the 1940 Act. PIMCO does not believe that the restrictions on transactions with the affiliated brokers described above will materially adversely affect its ability to provide services to the Fund, the Fund’s ability to take advantage of market opportunities, or the Fund’s overall performance.

Pursuant to an investment management agreement between the Investment Manager and the Fund (the “Investment Management Agreement”), the Fund has agreed to pay the Investment Manager an annual fee, payable monthly, in an amount equal to 0.650% of the Fund’s average daily net assets, including daily net assets attributable to any preferred shares that may be outstanding. Average daily net assets means an average of all the determinations of the Fund’s net assets during a given month at the close of business on each business day during such month.

under the terms of the Investment Management Agreement, subject to the general supervision of the Board of Trustees, PIMCO shall provide or cause to be furnished all supervisory and administrative and other services reasonably necessary for the operation of the Fund under what is essentially an all-in fee structure, including but not limited to the supervision and coordination of matters relating to the operation of the Fund, including any necessary coordination among the custodian, transfer agent, dividend disbursing agent, and recordkeeping agent (including pricing and valuation of the Fund), accountants, attorneys, auction agents and other parties performing services or operational functions for the Fund; the provision of adequate personnel, office space, communications facilities, and other facilities necessary for the effective supervision and administration of the Fund, as well as the services of a sufficient number of persons competent to perform such supervisory and administrative and clerical functions as are necessary for compliance with federal securities laws and other applicable laws; the maintenance of the books and records of the Fund; the preparation of all federal, state, local and foreign tax returns and reports for the Fund; the provision of administrative services to shareholders for the Fund including the maintenance of a shareholder information telephone number, the provision of certain statistical information and performance of the Fund, an internet website (if requested), and maintenance of privacy protection systems and procedures; the preparation and filing of such registration statements and other documents with such authorities as may be required to register and maintain the listing of the shares of the Fund; the taking of other such actions as may be required by applicable law (including establishment and maintenance of a compliance program for the Fund); and the preparation, filing and distribution of proxy materials, periodic reports to shareholders and other regulatory filings.

In addition, under the Investment Management Agreement, PIMCO will procure, at its own expense, the following services, and will bear expenses associated with the following for the Fund: a custodian or custodians for the Fund to provide for the safekeeping of the Fund’s assets; a recordkeeping agent to maintain the portfolio accounting records for the Fund; a transfer agent for the Fund; a dividend disbursing agent and/or registrar for the Fund; all audits by the Fund’s independent public accountant (except fees to auditors associated with satisfying rating agency requirements for preferred shares or other securities issued by the Fund and other related requirements in the Fund’s organizational documents); valuation services; maintaining the Fund’s tax records; all costs and/or fees incident to meetings of the Fund’s shareholders, the preparation, printing and mailing of the Fund’s prospectuses (although the Fund will bear such expenses in connection with the offerings made pursuant to the Prospectus as noted below), notices and proxy statements, press releases and reports to its Shareholders, the filing of reports with regulatory bodies, the maintenance of the Fund’s existence and qualification to do business, the expense of issuing, redeeming, registering and qualifying for sale, common shares with the federal and state securities authorities, and the expense of qualifying and listing Shares with any securities exchange or other trading system; legal services (except for extraordinary legal expenses); costs of printing certificates representing Shares of the Fund; the Fund’s pro rata portion of its fidelity bond and other insurance premiums; and association membership dues.

portfolio transaction expenses incurred by or for the Fund (including, without limitation, fees and expenses of outside legal counsel or third-party consultants retained in connection with reviewing, negotiating and structuring specialized loan and other investments made by the Fund, subject to specific or general authorization by the Board); expenses of the Fund’s securities lending (if any), including any securities lending agent fees, as governed by a separate securities lending agreement; costs, including interest expenses, of borrowing money or engaging in other types of leverage financing, including, without limitation, through the use by the Fund of reverse repurchase agreements, tender option bonds, bank borrowings and credit facilities; costs, including dividend cost and/or interest expenses and other costs (including, without limitation, offering and related legal costs, fees to brokers, fees to auction agents, fees to transfer agents, fees to ratings agencies and fees to auditors associated with satisfying ratings agency requirements for preferred shares or other securities issued by the Fund and other related requirements in a Fund’s organizational documents) associated with the Fund’s issuance, offering, redemption and maintenance of preferred shares, commercial paper or other senior securities for the purpose of incurring leverage; fees and expenses of any underlying funds or other pooled vehicles in which the Fund invests; dividend and interest expenses on short positions taken by the Fund; organizational and offering expenses of the Fund, including with respect to share offerings following the Fund’s initial offering, such as rights and shelf offerings (including expenses associated with offerings made pursuant to the Prospectus), and expenses associated with tender offers and other share repurchases and redemptions; extraordinary expenses including extraordinary legal expenses as may arise, including expenses incurred in connection with litigation, proceedings, other claims, and the legal obligations of the Fund to indemnify its Trustees, officers, employees, shareholders, distributors, and agents with respect thereto; and expenses of the Fund which are capitalized in accordance with generally accepted accounting principles.

Because the fees received by the Investment Manager are based on the average daily net assets of the Fund (including any assets attributable to the ARPS and any other preferred shares that may be outstanding), the Investment Manager has a financial incentive for the Fund to maintain and utilize preferred shares, which may create a conflict of interest between the Investment Manager, on the one hand, and the holders of the Fund’s Common Shares, on the other hand. The fees received by the Investment Manager are not, however, charged on asset attributable to leverage obtained by the Fund other than through preferred shares.

Pursuant to the Investment Management Agreement, the Fund paid the Investment Manager a total of $8,119,800 for the fiscal year ended July 31, 2017, $7,572,794 for the fiscal year ended July 31, 2016, $5,606,911 for the fiscal period ended July 31, 2015¹ and $8,628,618 for the fiscal year ended November 30, 2014.

The Investment Management Agreement was approved by the Trustees of the Fund (including all of the Trustees who are not “interested persons” of the Investment Manager). By its terms the Investment Management Agreement continues in force with respect to the Fund for an initial one year period, and continues in force from year to year thereafter, but only so long as its continuance is approved at least annually by (i) vote, cast in person at a meeting called for that purpose, of a

¹ On December 16, 2014, the Board approved a change of the Fund’s fiscal year end from November 30 to July 31. Information is provided for the “stub” period from December 1, 2014 through the Fund’s new fiscal year end of July 31, 2015

majority of those Trustees who are not “interested persons” of the Investment Manager or the Fund, and (ii) by the full Board of Trustees or the vote of a majority of the outstanding shares of all classes of the Fund. The Investment Management Agreement automatically terminates on assignment. The Investment Management Agreement may be terminated on not less than 60 days’ notice by the Investment Manager to the Fund or by the Fund to the Investment Manager.

The Investment Management Agreement provides that the Investment Manager shall not be subject to any liability in connection with the performance of its services thereunder in the absence of willful misfeasance, bad faith, gross negligence or reckless disregard of its obligations and duties.

Other Accounts Managed. Alfred T. Murata and Mohit Mittal, the portfolio managers who are jointly and primarily responsible for the day-to-day management of the Fund, also manage other registered investment companies, other pooled investment vehicles and other accounts, as indicated in the table below. The following table identifies, as of July 31, 2017: (i) the number of other registered investment companies, pooled investment vehicles and other accounts managed by the portfolio manager (exclusive of the Fund); and (ii) the total assets of such other companies, vehicles and accounts, and the number and total assets of such other companies, vehicles and accounts with respect to which the advisory fee is based on performance. The information includes amounts managed by a team, committee or other group that includes the portfolio manager.

From time to time, potential and actual conflicts of interest may arise between a portfolio manager’s management of the investments of the Fund, on the one hand, and the management of other accounts, on the other. Potential and actual conflicts of interest may also arise as a result of

PIMCO’s other business activities and PIMCO’s possession of material non-public information about an issuer. Other accounts managed by a portfolio manager might have similar investment objectives or strategies as the Fund, track the same index as the Fund or otherwise hold, purchase, or sell securities that are eligible to be held, purchased or sold by the Fund. The other accounts might also have different investment objectives or strategies than the Fund. Potential and actual conflicts of interest may also arise as a result of PIMCO serving as investment adviser to accounts that invest in the Fund. In this case, such conflicts of interest could in theory give rise to incentives for PIMCO to, among other things, vote proxies of the Fund in a manner beneficial to the investing account but detrimental to the Fund. Conversely, PIMCO’s duties to the Fund, as well as regulatory or other limitations applicable to the Fund, may affect the courses of action available to PIMCO-advised accounts (including certain funds) that invest in the Fund in a manner that is detrimental to such investing accounts. In addition, regulatory restrictions, actual or potential conflicts of interest or other considerations may cause PIMCO to restrict or prohibit participation in certain investments.

Because PIMCO is affiliated with Allianz, a large multi-national financial institution, conflicts similar to those described below may occur between the Fund and other accounts managed by PIMCO and PIMCO’s affiliates or accounts managed by those affiliates. Those affiliates (or their clients), which generally operate autonomously from PIMCO, may take actions that are adverse to the Fund or other accounts managed by PIMCO. In many cases, PIMCO will not be in a position to mitigate those actions or address those conflicts, which could adversely affect the performance of the Fund or other accounts managed by PIMCO.

Knowledge and Timing of Fund Trades. A potential conflict of interest may arise as a result of the portfolio manager’s day-to-day management of the Fund. Because of their positions with the Fund, the portfolio managers know the size, timing and possible market impact of the Fund’s trades. It is theoretically possible that the portfolio managers could use this information to the advantage of other accounts they manage and to the possible detriment of the Fund.

Investment Opportunities. A potential conflict of interest may arise as a result of the portfolio manager’s management of a number of accounts with varying investment guidelines. Often, an investment opportunity may be suitable for both the Fund and other accounts managed by the portfolio manager, but may not be available in sufficient quantities for both the Fund and the other accounts to participate fully. In addition, regulatory issues applicable to PIMCO or the Fund or other accounts may result in the Fund not receiving securities that may otherwise be appropriate for it. Similarly, there may be limited opportunity to sell an investment held by the Fund and another account. PIMCO has adopted policies and procedures reasonably designed to allocate investment opportunities on a fair and equitable basis over time.

Under PIMCO’s allocation procedures, investment opportunities are allocated among various investment strategies based on individual account investment guidelines and PIMCO’s investment outlook. PIMCO has also adopted additional procedures to complement the general trade allocation policy that are designed to address potential conflicts of interest due to the side-by-side management of the Fund and certain pooled investment vehicles, including investment opportunity allocation issues.

Conflicts potentially limiting the Fund’s investment opportunities may also arise when the Fund and other PIMCO clients invest in different parts of an issuer’s capital structure, such as when the Fund owns senior debt obligations of an issuer and other clients own junior tranches of the same issuer.

In such circumstances, decisions over whether to trigger an event of default, over the terms of any workout, or how to exit an investment may result in conflicts of interest. In order to minimize such conflicts, a portfolio manager may avoid certain investment opportunities that would potentially give rise to conflicts with other PIMCO clients or PIMCO may enact internal procedures designed to minimize such conflicts, which could have the effect of limiting the Fund’s investment opportunities. Additionally, if PIMCO acquires material non-public confidential information in connection with its business activities for other clients, a portfolio manager may be restricted from purchasing securities or selling securities for the Fund. Moreover, the Fund or other accounts managed by PIMCO may invest in a transaction in which one or more other funds or accounts managed by PIMCO are expected to participate, or already have made or will seek to make, an investment. Such funds or accounts may have conflicting interests and objectives in connection with such investments, including, for example and without limitation, with respect to views on the operations or activities of the issuer involved, the targeted returns from the investment, and the timeframe for, and method of, exiting the investment. Additionally, a fund or other account managed by PIMCO may take an investment position or action that may be different from, or inconsistent with, an investment position or action taken by another fund or other account managed by PIMCO having similar or differing investment objectives. These positions and actions may adversely impact the Fund. For example, the Fund may buy a security and another fund or other account managed by PIMCO may establish a short position in that same security or in another security issued by the same issuer. The subsequent short sale may result in a decrease in the price of the security that the first fund holds. When making investment decisions where a conflict of interest may arise, PIMCO will endeavor to act in a fair and equitable manner as between the Fund and other clients; however, in certain instances the resolution of the conflict may result in PIMCO acting on behalf of another client in a manner that may not be in the best interest, or may be opposed to the best interest, of the Fund.

Performance Fees. A portfolio manager may advise certain accounts with respect to which the management fee is based entirely or partially on performance. Performance fee arrangements may create a conflict of interest for the portfolio manager in that the portfolio manager may have an incentive to allocate the investment opportunities that he or she believes might be the most profitable to such other accounts instead of allocating them to the Fund. PIMCO has adopted policies and procedures reasonably designed to allocate investment opportunities between the Fund and certain pooled investment vehicles on a fair and equitable basis over time.

PIMCO’s approach to compensation seeks to provide professionals with a Total Compensation Plan and process that is driven by PIMCO’s mission and values. Key Principles on Compensation Philosophy include:

The Total Compensation Plan consists of three components. The compensation program for portfolio managers is designed to align with clients’ interests, emphasizing each portfolio manager’s ability to generate long-term investment success for PIMCO’s clients. A portfolio manager’s compensation is not based solely on the performance of the Fund or any other account managed by that portfolio manager:

Base Salary – Base salary is determined based on core job responsibilities, positions/levels and market factors. Base salary levels are reviewed annually, when there is a significant change in job responsibilities or position, or a significant change in market levels.

Performance Bonus – Performance bonuses are designed to reward risk-adjusted performance and contributions to PIMCO’s broader investment process. The compensation process is not formulaic and the following non-exhaustive list of qualitative and quantitative criteria are considered when determining the total compensation for portfolio managers:

PIMCO’s partnership culture further rewards strong long term risk adjusted returns with promotion decisions almost entirely tied to long term contributions to the investment process. 10-year performance can also be considered, though not explicitly as part of the compensation process.

Deferred Compensation – Long Term Incentive Plan (“LTIP”) and/or M Options are awarded to key professionals. Employees who reach a total compensation threshold are delivered their annual compensation in a mix of cash and/or deferred compensation. PIMCO incorporates a progressive allocation of deferred compensation as a percentage of total compensation, which is in line with market practices.

Eligibility to participate in LTIP and the M Unit program is contingent upon continued employment at PIMCO and all other applicable eligibility requirements.

Profit Sharing Plan. Portfolio managers who are Managing Directors of PIMCO receive compensation from a non-qualified profit sharing plan consisting of a portion of PIMCO’s net profits. Portfolio managers who are Managing Directors receive an amount determined by the Compensation Committee, based upon an individual’s overall contribution to the firm.

The following table discloses the dollar range of equity securities beneficially owned by the portfolio managers of the Fund. The information is as of July 31, 2017.

PIMCO has adopted written proxy voting policies and procedures (“Proxy Policy”) as required by Rule 206(4)-6 under the Investment Advisers Act of 1940. The Fund has adopted the Proxy Policy of PIMCO when voting proxies on behalf of the Fund. In addition to covering the voting of equity securities, the Proxy Policy also applies generally to voting and/or consent rights of fixed income securities, including but not limited to, plans of reorganization, and waivers and consents under applicable indentures. The Proxy Policy does not apply, however, to consent rights that primarily entail decisions to buy or sell investments, such as tender or exchange offers, conversions, put options, redemption and Dutch auctions. The Proxy Policy is designed and implemented in a manner reasonably expected to ensure that voting and consent rights (collectively, “proxies”) are exercised in the best interests of accounts.

With respect to the voting of proxies relating to equity securities, PIMCO has selected an unaffiliated third party proxy research and voting service (“Proxy Voting Service”), to assist it in researching and voting proxies. With respect to each proxy received, the Proxy Voting Service researches the financial implications of the proposals and provides a recommendation to PIMCO as to how to vote on each proposal based on the Proxy Voting Service’s research of the individual facts and circumstances and the Proxy Voting Service’s application of its research findings to a set of guidelines that have been approved by PIMCO. Upon the recommendation of the applicable portfolio managers, PIMCO may determine to override any recommendation made by the Proxy Voting Service. In the event that the Proxy Voting Service does not provide a recommendation with respect to a proposal, PIMCO may determine to vote on the proposals directly.

With respect to the voting of proxies relating to fixed income securities, PIMCO’s fixed income credit research group (the “Credit Research Group”) is responsible for researching and issuing recommendations for voting proxies. With respect to each proxy received, the Credit Research Group researches the financial implications of the proxy proposal and makes voting recommendations specific for each account that holds the related fixed income security. PIMCO considers each proposal regarding a fixed income security on a case-by-case basis taking into consideration any relevant contractual obligations as well as other relevant facts and circumstances at the time of the vote. Upon the recommendation of the applicable portfolio managers, PIMCO may determine to override any recommendation made by the Credit Research Group. In the event that the Credit Research Group does not provide a recommendation with respect to a proposal, PIMCO may determine to vote the proposal directly.

PIMCO may determine not to vote a proxy for an equity or fixed income security if: (1) the effect on the applicable account’s economic interests or the value of the portfolio holding is insignificant in relation to the account’s portfolio; (2) the cost of voting the proxy outweighs the possible benefit to the applicable account, including, without limitation, situations where a jurisdiction imposes share blocking restrictions which may affect the ability of the portfolio managers to effect trades in the related security; or (3) PIMCO otherwise has determined that it is consistent with its fiduciary obligations not to vote the proxy.

In the event that the Proxy Voting Service or the Credit Research Group, as applicable, does not provide a recommendation or the portfolio managers of a client account propose to override a recommendation by the Proxy Voting Service, or the Credit Research Group, as applicable, PIMCO will review the proxy to determine whether there is a material conflict between PIMCO and the applicable account or among PIMCO-advised accounts. If no material conflict exists, the proxy will be voted according to the portfolio managers’ recommendation. If a material conflict does exist, PIMCO will seek to resolve the conflict in good faith and in the best interests of the applicable client account, as provided by the Proxy Policy. The Proxy Policy permits PIMCO to seek to resolve material conflicts of interest by pursuing any one of several courses of action. With respect to material conflicts of interest between PIMCO and a client account, the Proxy Policy permits PIMCO to either: (i) convene a committee to assess and resolve the conflict (the “Proxy Conflicts Committee”); or (ii) vote in accordance with protocols previously established by the Proxy Policy, the Proxy Conflicts Committee and/or other relevant procedures approved by PIMCO’s Legal and Compliance department with respect to specific types of conflicts. With respect to material conflicts of interest between one or more PIMCO-advised accounts, the Proxy Policy permits PIMCO to: (i) designate a PIMCO portfolio manager who is not subject to the conflict to determine how to vote the proxy if the conflict exists between two accounts with at least one portfolio manager in common; or (ii) permit the respective portfolio managers to vote the proxies in accordance with each client account’s best interests if the conflict exists between client accounts managed by different portfolio managers.

PIMCO will supervise and periodically review its proxy voting activities and the implementation of the Proxy Policy.

Information about how PIMCO voted the Fund’s proxies for the most recent twelve month period ended June 30th (Form N-PX) will be available no later than the following August 31^st, without charge, upon request, by calling the Fund at (844) 33-PIMCO (844-337-4626), on the Fund’s website at www.pimco.com and on the SEC’s website at http://www.sec.gov.

Investment decisions for the Fund and for the other investment advisory clients of PIMCO are made with a view to achieving their respective investment objectives. Investment decisions are the product of many factors in addition to basic suitability for the particular client involved (including the Fund). Some securities considered for investments by the Fund also may be appropriate for other clients served by PIMCO. Thus, a particular security may be bought or sold for certain clients even though it could have been bought or sold for other clients at the same time, including accounts in which PIMCO, its affiliates and its employees may have a financial interest. If a purchase or sale of securities consistent with the investment policies of the Fund and one or more of these clients served by PIMCO is considered at or about the same time, transactions in such securities will be allocated among the Fund and other clients pursuant to PIMCO’s trade allocation policy, as applicable, that is designed to ensure that all accounts, including the Fund, are treated fairly, equitably, and in a non-preferential manner, such that allocations are not based upon fee structure or portfolio manager preference. PIMCO may acquire on behalf of its clients (including the Fund) securities or other financial instruments providing exposure to different aspects of the capital and debt structure of an issuer, including without limitation those that relate to senior and junior/subordinate obligations of such issuer. In certain circumstances, the interests of those clients exposed to one portion of the issuer’s capital and debt structure may diverge from those clients exposed to a different portion of the issuer’s capital and debt structure. PIMCO may advise some clients or take actions for them in their best interests with respect to their exposures to an issuer’s capital and debt structure that may diverge from the interests of other clients with different exposures to the same issuer’s capital and debt structure.

PIMCO may aggregate orders for the Fund with simultaneous transactions entered into on behalf of its other clients when, in its reasonable judgment, aggregation may result in an overall economic benefit to the Fund and the other clients in terms of pricing, brokerage commissions or other expenses. When feasible, PIMCO allocates trades prior to execution. When pre-execution allocation is not feasible, PIMCO promptly allocates trades following established and objective procedures. Allocations generally are made at or about the time of execution and before the end of the trading day. As a result, one account may receive a price for a particular transaction that is different from the price received by another account for a similar transaction on the same day. In general, trades are allocated among portfolio managers on a pro rata basis (to the extent a portfolio manager decides to participate fully in the trade), for further allocation by each portfolio manager among that manager’s eligible accounts. In allocating trades among accounts, portfolio managers generally consider a number of factors, including, but not limited to, each account’s deviation (in

terms of risk exposure and/or performance characteristics) from a relevant model portfolio, each account’s investment objectives, restrictions and guidelines, its risk exposure, its available cash, and its existing holdings of similar securities. Once trades are allocated, they may be reallocated only in unusual circumstances due to recognition of specific account restrictions. In some cases, PIMCO may sell a security on behalf of a client, including the Fund, to a broker-dealer that thereafter may be purchased for the accounts of one or more other clients, including the Fund, from that or another broker-dealer. PIMCO have adopted procedures they believe are reasonably designed to obtain the best execution for the transactions by each account.

There is generally no stated commission in the case of fixed-income securities, which are often traded in the over-the-counter markets, but the price paid by the Fund usually includes an undisclosed dealer commission or mark-up. In underwritten offerings, the price paid by the Fund includes a disclosed, fixed commission or discount retained by the underwriter or dealer. Transactions on U.S. stock exchanges and other agency transactions involve the payment by the Fund of negotiated brokerage commissions. Such commissions vary among different brokers. Also, a particular broker may charge different commissions according to such factors as the difficulty and size of the transaction. Transactions in foreign securities generally involve the payment of fixed brokerage commissions, which are generally higher than those in the United States. Transactions in fixed income securities on certain foreign exchanges may involve commission payments.

PIMCO places all orders for the purchase and sale of portfolio securities, options, futures contracts, swap agreements and other instruments for the Fund and buys and sells such securities, options, futures, swap agreements and other instruments for the Fund through a substantial number of brokers and dealers. In so doing, PIMCO uses its best efforts to obtain for the Fund the best execution available, except to the extent it may be permitted to pay higher brokerage commissions as described below. In seeking best execution, PIMCO, having in mind the Fund’s best interests, considers all factors it deems relevant, including, by way of illustration, price, the size of the transaction, the nature of the market for the security, the amount of the commission, the timing of the transaction taking into account market prices and trends, the reputation, experience and financial stability of the broker-dealer involved and the quality of service rendered by the broker-dealer in other transactions. Changes in the aggregate amount of brokerage commissions paid by the Fund from year-to-year may be attributable to changes in the asset size of the Fund, the volume of the portfolio transactions effected by the Fund, the types of instruments in which the Fund invests, or the rates negotiated by PIMCO on behalf of the Fund.

The Fund paid $1,164 in brokerage commissions during the fiscal year ended July 31, 2017. The Fund did not pay any brokerage commissions during the fiscal year ended July 31, 2016, the fiscal period ended July 31, 2015² and for the fiscal year ended November 30, 2014.

PIMCO places orders for the purchase and sale of portfolio investments for the Fund’s account with brokers or dealers selected by it in its discretion. In effecting purchases and sales of portfolio securities for the account of the Fund, PIMCO will seek the best price and execution of the Fund’s orders. In doing so, the Fund may pay higher commission rates than the lowest available when PIMCO believes it is reasonable to do so in light of the value of the brokerage and research services provided by the broker effecting the transaction, as discussed below.

² On December 16, 2014, the Board approved a change of the Fund’s fiscal year end from November 30 to July 31. Information is provided for the “stub” period from December 1, 2014 through the Fund’s new fiscal year end of July 31, 2015

It has for many years been a common practice in the investment advisory business for advisers of investment companies and other institutional investors to receive research and brokerage products and services (together, “services”) from broker-dealers that execute portfolio transactions for the clients of such advisers. Consistent with this practice, PIMCO may receive research services from many broker-dealers with which PIMCO places the Fund’s portfolio transactions. PIMCO also may receive research or research related credits from brokers that are generated from underwriting commissions when purchasing new issues of fixed-income securities or other assets for the Fund. These services, which in some cases may also be purchased for cash, include such matters as general economic and security market reviews, industry and company reviews, evaluations of securities and recommendations as to the purchase and sale of securities and services related to the execution of securities transactions. Some of these services are of value to PIMCO in advising various of its clients (including the Fund), although not all of these services are necessarily useful and of value in managing the Fund. Conversely, research and brokerage services provided to the Fund by broker-dealers in connection with trades executed on behalf of other clients of PIMCO may be useful to PIMCO in managing the Fund, although not all of these services may be necessarily useful and of value to PIMCO in managing such other clients.

In reliance on the “safe harbor” provided by Section 28(e) of the Exchange Act, as amended, PIMCO may cause the Fund to pay broker-dealers which provide them with “brokerage and research services” (as defined in the Exchange Act) an amount of commission for effecting a securities transaction for the Fund in excess of the commission which another broker-dealer would have charged for effecting that transaction if PIMCO determines in good faith that the commission is reasonable in relation to the value of the brokerage and research services provided by the broker-dealer viewed in terms of either a particular transaction or PIMCO’s overall responsibilities to the advisory accounts for which PIMCO exercises investment discretion.

PIMCO may place orders for the purchase and sale of exchanged-listed portfolio securities with a broker-dealer that is an affiliate of PIMCO where, in the judgment of PIMCO, such firm will be able to obtain a price and execution at least as favorable as other qualified broker-dealers.

Pursuant to rules of the SEC, a broker-dealer that is an affiliate of PIMCO may receive and retain compensation for effecting portfolio transactions for the Fund on a national securities exchange of which the broker-dealer is a member if the transaction is “executed” on the floor of the exchange by another broker which is not an “associated person” of the affiliated broker-dealer, and if there is in effect a written contract between PIMCO and the Fund expressly permitting the affiliated broker-dealer to receive and retain such compensation.

SEC rules further require that commissions paid to such an affiliated broker dealer, or PIMCO by the Fund on exchange transactions not exceed “usual and customary brokerage commissions.” The rules define “usual and customary” commissions to include amounts which are “reasonable and fair compared to the commission, fee or other remuneration received or to be received by other brokers in connection with comparable transactions involving similar securities being purchased or sold on a securities exchange during a comparable period of time.”

The Fund did not pay any commissions to affiliated brokers during the fiscal years ended July 31, 2017, July 31, 2016, July 31, 2015³ and November 30, 2014.

The following table lists the regular brokers or dealers of the Fund whose securities the Fund acquired during the fiscal year ended July 31, 2017, as well as the Fund’s holdings in such brokers or dealers as of July 31, 2017.

See “Distributions” in the Prospectus for information relating to distributions to Fund shareholders.

For U.S. federal income tax purposes, the Fund is currently required to allocate each type of its income (such as ordinary income and net capital gain), if any, between and among Common Shares and each series of Preferred Shares in proportion to total distributions paid to each class for the tax year.

While any Preferred Shares are outstanding, the Fund may not declare any cash dividend or other distribution on its Common Shares unless: (i) immediately after such transaction, the Fund would satisfy Moody’s Ratings Agency Preferred Shares Asset Coverage and 1940 Act Preferred Shares Asset Coverage would be satisfied (each as defined and described under “Description of Capital Structure – Rating Agency Guidelines and Asset Coverage” in the Prospectus); (ii) full cumulative dividends on the Preferred Shares due on or prior to the date of the transaction have been declared and paid or shall have been declared and sufficient funds for the payment thereof deposited with the auction agent for the Preferred Shares; and (iii) the Fund has redeemed the full number of Preferred Shares required to be redeemed by any provision for mandatory redemption contained in the Bylaws. See “Preferred Shares Redemption.” This latter limitation on the Fund’s ability to make distributions on its Common Shares could cause the Fund to incur income and excise tax and, under certain circumstances, impair the ability of the Fund to maintain its qualification for taxation as a regulated investment company. See “Taxation.”

³ On December 16, 2014, the Board approved a change of the Fund’s fiscal year end from November 30 to July 31. Information is provided for the "stub" period from December 1, 2014 through the Fund’s new fiscal year end of July 31, 2015.

The Board of Trustees has declared a dividend of $0.13 per Common Share payable on September 1, 2017. The Board of Trustees has also declared a dividend of $0.13 per Common Share payable on October 2, 2017.

The Fund’s Declaration authorizes the issuance of an unlimited number of Common Shares. The Common Shares currently outstanding have been issued with a par value of $0.00001 per share. All Common Shares of the Fund have equal rights as to the payment of dividends and the distribution of assets upon liquidation of the Fund. The Common Shares currently outstanding have been fully paid and, subject to matters discussed in “Anti-Takeover and Other Provisions in the Declaration of Trust—Shareholder Liability” below, are non-assessable, and have no pre-emptive or conversion rights or rights to cumulative voting. At any time when the Fund’s ARPS are outstanding, Common Shareholders will not be entitled to receive any distributions from the Fund unless all accrued dividends on ARPS have been paid, and unless asset coverage (as defined in the 1940 Act) with respect to ARPS would be at least 200% after giving effect to such distributions. See “Description of Capital Structure” in the Prospectus.

The Common Shares are listed on the NYSE. The Fund intends to hold annual meetings of shareholders so long as the Common Shares are listed on a national securities exchange and such meetings are required as a condition to such listing.

Shares of closed-end investment companies may frequently trade at prices lower than net asset value. Shares of closed-end investment companies like the Fund that invest predominantly in corporate debt obligations have during some periods traded at prices higher than net asset value and during other periods traded at prices lower than net asset value. There can be no assurance that Common Shares or shares of other similar funds will trade at a price higher than net asset value in the future. Net asset value will be reduced immediately following any offering of ARPS by the costs of that offering paid by the Fund. Net asset value generally increases when interest rates decline, and decreases when interest rates rise, and these changes are likely to be greater in the case of a fund, such as the Fund, having a leveraged capital structure. Whether investors realize gains or losses upon the sale of Common Shares will not depend upon the Fund’s net asset value but will depend entirely upon whether the market price of the Common Shares at the time of sale is above or below the original purchase price for the shares. Since the market price of the Fund’s Common Shares will be determined by factors beyond the control of the Fund, the Fund cannot predict whether the Common Shares will trade at, below, or above net asset value or at, below or above the initial public offering price. Accordingly, the Common Shares are designed primarily for long-term investors, and investors in the Common Shares should not view the Fund as a vehicle for trading purposes. See “Repurchase of Common Shares; Conversion to Open-End Fund.”

See “Description of Capital Structure” in the Prospectus for information relating to the ARPS.

As used in this Statement of Additional Information and in the Prospectus, unless otherwise noted, the Fund’s “net assets” include assets of the Fund attributable to any outstanding ARPS, with no deduction for the liquidation preference of the ARPS. Solely for financial reporting purposes, however, the Fund is required to exclude the liquidation preference of ARPS from “net assets,” so long as the ARPS have redemption features that are not solely within the control of the Fund. For all regulatory and tax purposes, the Fund’s ARPS will be treated as stock (rather than indebtedness).

Under Massachusetts law, shareholders could, under certain circumstances, be held personally liable for the obligations of the Fund. However, the Declaration contains an express disclaimer of shareholder liability for acts or obligations of the Fund and requires that notice of such limited liability be given in each agreement, obligation or instrument entered into or executed by the Fund or the Trustees. The Declaration also provides for indemnification out of the Fund’s assets and property for all loss and expense of any shareholder held personally liable on account of being or having been a shareholder. Thus, the risk of a shareholder incurring financial loss on account of shareholder liability should be limited to circumstances in which such disclaimer is inoperative or the Fund is unable to meet its obligations, and thus should be considered remote.

As described below, the Declaration includes provisions that could limit the ability of other entities or persons to acquire control of the Fund, convert the Fund to open-end status or to change the composition of its Board of Trustees, and could have the effect of depriving shareholders of opportunities to sell their shares at a premium over prevailing market prices by discouraging a third party from seeking to obtain control of the Fund.

The Fund’s Trustees are divided into three classes (Class I, Class II and Class III), having initial terms of one, two and three years, respectively. At each annual meeting of shareholders, the term of one class will expire and each Trustee elected to that class will hold office until the third annual meeting thereafter. The classification of the Board of Trustees in this manner could delay for an additional year the replacement of a majority of the Board of Trustees. In addition, the Declaration provides that a Trustee may be removed only for cause and only (i) by action of at least seventy-five percent (75%) of the outstanding shares of the classes or series of shares entitled to vote for the election of such Trustee, or (ii) by written instrument, signed by at least seventy-five percent (75%) of the remaining Trustees, specifying the date when such removal shall become effective. Cause for these purposes shall require willful misconduct, dishonesty or fraud on the part of the Trustee in the conduct of his office or such Trustee being convicted of a felony. Except as provided in the next paragraph, the affirmative vote or consent of at least seventy-five percent (75%) of the Board of Trustees and at least seventy-five percent (75%) of the holders of shares of the Fund outstanding and entitled to vote thereon are required to authorize any of the following transactions (each a “Material Transaction”): (1) a merger, consolidation or share exchange of the Fund or any series or class of shares of the Fund with or into any other person or company, or of any such person or company with or into the Fund or any such series or class of shares; (2) the issuance or transfer by the Fund or any series or class of shares (in one or a series of transactions in any twelve-month period) of any securities of the Fund or such series or class to any other person or entity for cash, securities or other property (or combination thereof) having an aggregate fair market value of $1,000,000 or more, excluding sales of securities of the Fund or such series or class in connection with a public offering, issuances of securities of the Fund or such series or class pursuant to a dividend reinvestment plan adopted by the Fund and issuances of securities of the Fund or such series or class upon the exercise of any stock subscription rights distributed by the Fund; or (3) a

sale, lease, exchange, mortgage, pledge, transfer or other disposition by the Fund or any series or class of shares (in one or a series of transactions in any twelve-month period) to or with any person of any assets of the Fund or such series or class having an aggregate fair market value of $1,000,000 or more, except for transactions in securities effected by the Fund or such series or class in the ordinary course of its business. The same affirmative votes are required with respect to any shareholder proposal as to specific investment decisions made or to be made with respect to the Fund’s assets or the assets of any series or class of shares of the Fund. Notwithstanding the approval requirements specified in the preceding paragraph, the Declaration requires no vote or consent of the Fund’s shareholders to authorize a Material Transaction if the transaction is approved by a vote of both a majority of the Board of Trustees and seventy-five percent (75%) of the Continuing Trustees (as defined below), so long as all other conditions and requirements, if any, provided for in the Fund’s Bylaws and applicable law (including any shareholder voting rights under the 1940 Act) have been satisfied.

In addition, the Declaration provides that the Fund may be terminated at any time by vote or consent of at least seventy-five percent (75%) of the Fund’s shares entitled to vote or, alternatively, by vote or consent of both a majority of the Board of Trustees and seventy-five percent (75%) of the Continuing Trustees (as defined below) upon written notice to shareholders of the Fund.

In certain circumstances, the Declaration also imposes shareholder voting requirements that are more demanding than those required under the 1940 Act in order to authorize a conversion of the Fund from a closed-end to an open-end investment company. See “Repurchase of Common Shares; Conversion to Open-End Fund” below.

As noted, the voting provisions described above could have the effect of depriving Common Shareholders of an opportunity to sell their Common Shares at a premium over prevailing market prices by discouraging a third party from seeking to obtain control of the Fund in a tender offer or similar transaction. In the view of the Fund’s Board of Trustees, however, these provisions offer several possible advantages, including: (1) requiring persons seeking control of the Fund to negotiate with its management regarding the price to be paid for the amount of Common Shares required to obtain control; (2) promoting continuity and stability; and (3) enhancing the Fund’s ability to pursue long-term strategies that are consistent with its investment objectives and management policies. The Board of Trustees has determined that the voting requirements described above, which are generally greater than the minimum requirements under the 1940 Act, are in the best interests of the Fund’s Common Shareholders generally.

A “Continuing Trustee,” as used in the discussion above, is any member of the Fund’s Board of Trustees who either (i) has been a member of the Board for a period of at least thirty-six months (or since the commencement of the Fund’s operations, if less than thirty-six months) or (ii) was nominated to serve as a member of the Board of Trustees by a majority of the Continuing Trustees then members of the Board.

The foregoing is intended only as a summary and is qualified in its entirety by reference to the full text of the Declaration and the Fund’s Bylaws, both of which have been filed as exhibits to the Fund’s registration statement on file with the SEC.

The Declaration provides that the obligations of the Fund are not binding upon the Trustees of the Fund individually, but only upon the assets and property of the Fund, and that the Trustees shall not be liable for errors of judgment or mistakes of fact or law. Nothing in the Declaration, however, protects a Trustee against any liability to which he would otherwise be subject by reason of willful misfeasance, bad faith, gross negligence or reckless disregard of the duties involved in the conduct of his office.

The Fund is a closed-end investment company and as such its shareholders will not have the right to cause the Fund to redeem their shares. Instead, the Fund’s Common Shares will trade in the open market at a price that will be a function of several factors, including dividend levels and stability (which will in turn be affected by dividend and interest payments by the Fund’s portfolio holdings, regulations affecting the timing and character of Fund’s distributions, Fund expenses and other factors), portfolio credit quality, liquidity, call protection, market supply and demand, and similar factors relating to the Fund’s portfolio holdings. Shares of a closed-end investment company may frequently trade at prices lower than net asset value. The Fund’s Board will regularly monitor the relationship between the market price and net asset value of the Common Shares. If the Common Shares were to trade at a substantial discount to net asset value for an extended period of time, the Board may consider the repurchase of its Common Shares on the open market or in private transactions, the making of a tender offer for such shares or the conversion of the Fund to an open-end investment company. The Fund cannot assure you that the Board will decide to take or propose any of these actions, or that share repurchases or tender offers will actually reduce any market discount. The Fund has no present intention to repurchase its Common Shares and would do so only in the circumstances described in this section.

Notwithstanding the foregoing, at any time when the Fund’s ARPS are outstanding, the Fund may not purchase, redeem or otherwise acquire for consideration any of its Common Shares unless and only if: (i) immediately after such transaction, the Fund would satisfy Moody’s Ratings Agency Preferred Shares Asset Coverage and 1940 Act Preferred Shares Asset Coverage would be satisfied (each as defined and described under “Description of Capital Structure— Rating Agency Guidelines and Asset Coverage” in the Prospectus); (ii) full cumulative dividends on the Preferred Shares due on or prior to the date of the transaction have been declared and paid or shall have been declared and sufficient funds for the payment thereof deposited with the auction agent for the Preferred Shares; and (iii) the Fund has redeemed the full number of Preferred Shares required to be redeemed by any provision for mandatory redemption contained in the Bylaws.

Subject to its investment limitations, the Fund may borrow to finance the repurchase of shares or to make a tender offer. Interest on any borrowings to finance share repurchase transactions or the accumulation of cash by the Fund in anticipation of share repurchases or tenders will reduce the Fund’s net income. Any share repurchase, tender offer or borrowing that might be approved by the Board of Trustees would have to comply with the Securities Exchange Act of 1934, as amended, and the 1940 Act and the rules and regulations thereunder.

The Fund’s Board of Trustees may also from time to time consider submitting to the holders of the shares of beneficial interest of the Fund a proposal to convert the Fund to an open-end investment company. In determining whether to exercise its sole discretion to submit this issue to shareholders,

the Board of Trustees would consider all factors then relevant, including the relationship of the market price of the Common Shares to net asset value, the extent, if any, to which the Fund’s capital structure is leveraged and the possibility of re-leveraging, the spread, if any, between the yields on securities in the Fund’s portfolio and interest and dividend charges on ARPS issued by the Fund and general market and economic conditions.

The Declaration requires the affirmative vote or consent of holders of at least seventy-five percent (75%) of each class of the Fund’s shares entitled to vote on the matter to authorize a conversion of the Fund from a closed-end to an open-end investment company, unless the conversion is authorized by both a majority of the Board of Trustees and seventy-five percent (75%) of the Continuing Trustees (as defined above under “Anti-Takeover and Other Provisions in the Declaration of Trust—Anti-Takeover Provisions”). This seventy-five percent (75%) shareholder approval requirement is higher than is required under the 1940 Act. In the event that a conversion is approved by the Trustees and the Continuing Trustees as described above, the minimum shareholder vote required under the 1940 Act would be necessary to authorize the conversion. Currently, the 1940 Act would require approval of the holders of a “majority of the outstanding” Common Shares and ARPS voting together as a single class, and the holders of a “majority of the outstanding” ARPS voting as a separate class, in order to authorize a conversion.

If the Fund were to convert to an open-end company, it would be required to redeem all ARPS then outstanding (required in turn that it liquidate a portion of its investment portfolio) and the Fund’s Common Shares likely would no longer be listed on the NYSE. In contrast to a closed-end investment company, shareholders of an open-end investment company may require the company to redeem their shares at any time (except in certain circumstances as authorized by or under the 1940 Act) at their net asset value, less any redemption charge that is in effect at the time of redemption. In addition, if the Fund were to convert to an open-end company, it would likely have to significantly reduce any leverage it is then employing and would not be able to invest more than 15% of its net assets in illiquid securities, either or both of which may necessitate a substantial repositioning of the Fund’s investment portfolio, which may in turn generate substantial transaction costs, which would be borne by Common Shareholders, and may adversely affect Fund performance and Fund dividends. Shareholders of an open-end investment company may require the company to redeem their shares on any business day (except in certain circumstances as authorized by or under the 1940 Act) at their net asset value, less such redemption charge, if any, as might be in effect at the time of redemption. In order to avoid maintaining large cash positions or liquidating favorable investments to meet redemptions, open-end companies typically engage in a continuous offering of their shares. Open-end companies are thus subject to periodic asset in-flows and out-flows that can complicate portfolio management.

The repurchase by the Fund of its shares at prices below net asset value will result in an increase in the net asset value of those shares that remain outstanding. However, there can be no assurance that share repurchases or tenders at or below net asset value will result in the Fund’s shares trading at a price equal to their net asset value. Nevertheless, the fact that the Fund’s shares may be the subject of repurchase or tender offers at net asset value from time to time, or that the Fund may be converted to an open-end company, may reduce any spread between market price and net asset value that might otherwise exist.

In addition, a purchase by the Fund of its Common Shares will decrease the Fund’s total assets. This would likely have the effect of increasing the Fund’s expense ratio. Any purchase by the Fund of its Common Shares at a time when Preferred Shares, reverse repurchase agreements, credit default swaps or other forms of leverage are outstanding will increase the leverage applicable to the outstanding Common Shares then remaining. See the Prospectus under “Principal Risks of the Fund—Leverage Risk.”

Before deciding whether to take any action if the Fund’s Common Shares trade below net asset value, the Board of Trustees would consider all relevant factors, including the extent and duration of the discount, the liquidity of the Fund’s portfolio, the impact of any action that might be taken on the Fund or its shareholders and market considerations. Based on these considerations, even if the Fund’s shares should trade at a discount, the Board of Trustees may determine that, in the interest of the Fund and its shareholders, no action should be taken.

The following discussion of U.S. federal income tax consequences of investment in Common Shares of the Fund is based on the Code, U.S. Treasury regulations, and other applicable authority, as of the date of this Statement of Additional Information. These authorities are subject to change by legislative or administrative action, possibly with retroactive effect. The following discussion is only a summary of some of the important U.S. federal income tax considerations generally applicable to investments in Common Shares of the Fund. This summary does not purport to be a complete description of the U.S. federal income tax considerations applicable to an investment in Common Shares of the Fund. There may be other tax considerations applicable to particular shareholders. For example, except as otherwise specifically noted herein, we have not described certain tax considerations that may be relevant to certain types of holders subject to special treatment under the U.S. federal income tax laws, including shareholders subject to the U.S. federal alternative minimum tax, insurance companies, tax-exempt organizations, pension plans and trusts, regulated investment companies, dealers in securities, shareholders holding Common Shares through tax-advantaged accounts (such as 401(k) plans or individual retirement accounts), financial institutions, shareholders holding Common Shares as part of a hedge, straddle, or conversion transaction, entities that are not organized under the laws of the United States or a political subdivision thereof, and persons who are neither citizens nor residents of the United States. This summary assumes that investors hold Common Shares as capital assets (within the meaning of the Code). Shareholders should consult their own tax advisors regarding their particular situation and the possible application of U.S. federal, state, local, non-U.S. or other tax laws, and any proposed tax law changes.

The Fund has elected and intends each year to qualify and be eligible to be treated as a regulated investment company under Subchapter M of the Code. In order to qualify for the special tax treatment accorded regulated investment companies and their shareholders, the Fund must, among other things: (a) derive at least 90% of its gross income for each taxable year from (i) dividends, interest, payments with respect to certain securities loans, and gains from the sale or other disposition of stock, securities or foreign currencies, or other income (including but not limited to gains from options, futures, or forward contracts) derived with respect to its business of investing in such stock, securities, or currencies and (ii) net income derived from interests in “qualified publicly traded partnerships” (as defined below); (b) diversify its holdings so that, at the end of each quarter of the Fund’s taxable year, (i) at least 50% of the value of the Fund’s total assets consists of cash and cash items, U.S. government securities, securities of other regulated investment companies, and other securities limited in respect of any one issuer to a value not greater than 5% of the value of the

Fund’s total assets and not more than 10% of the outstanding voting securities of such issuer, and (ii) not more than 25% of the value of the Fund’s total assets is invested, including through corporations in which the Fund owns a 20% or more voting stock interest, (x) in the securities (other than those of the U.S. government or other regulated investment companies) of any one issuer or of two or more issuers that the Fund controls and that are engaged in the same, similar, or related trades or businesses, or (y) in the securities of one or more qualified publicly traded partnerships (as defined below); and (c) distribute with respect to each taxable year at least 90% of the sum of its investment company taxable income (as that term is defined in the Code without regard to the deduction for dividends paid—generally, taxable ordinary income and the excess, if any, of net short-term capital gains over net long-term capital losses) and any net tax-exempt interest income for such year.

In general, for purposes of the 90% gross income requirement described in paragraph (a) above, income derived from a partnership will be treated as qualifying income only to the extent such income is attributable to items of income of the partnership that would be qualifying income if realized directly by the regulated investment company. However, 100% of the net income derived from an interest in a “qualified publicly traded partnership” (a partnership (x) the interests in which are traded on an established securities market or are readily tradable on a secondary market or the substantial equivalent thereof and (y) that derives less than 90% of its income from the qualifying income described in paragraph (a)(i) above) will be treated as qualifying income. In general, such entities will be treated as partnerships for U.S. federal income tax purposes because they meet the passive income requirement under Code section 7704(c)(2). In addition, although in general the passive loss rules of the Code do not apply to regulated investment companies, such rules do apply to a regulated investment company with respect to items attributable to an interest in a qualified publicly traded partnership.

For purposes of the diversification test in (b) above, the term “outstanding voting securities of such issuer” will include the equity securities of a qualified publicly traded partnership. Also, for purposes of the diversification test in (b) above, the identification of the issuer (or, in some cases, issuers) of a particular Fund investment can depend on the terms and conditions of that investment. In some cases, identification of the issuer (or issuers) is uncertain under current law, and an adverse determination or future guidance by the IRS with respect to issuer identification for a particular type of investment may adversely affect the Fund’s ability to meet the diversification test in (b) above.

If the Fund qualifies as a regulated investment company that is accorded special tax treatment, the Fund will not be subject to U.S. federal income tax on income or gains distributed in a timely manner to Common Shareholders in the form of dividends (including Capital Gain Dividends, as defined below). If the Fund were to fail to meet the income, diversification, or distribution tests described above, the Fund could in some cases cure such failure, including by paying a Fund-level tax, paying interest, making additional distributions, or disposing of certain assets. If the Fund were ineligible to or otherwise did not cure such failure for any year, or were otherwise to fail to qualify as a regulated investment company accorded special tax treatment for such year, the Fund would be subject to tax on its taxable income at corporate rates, and all distributions from earnings and profits, including any distributions of net tax-exempt income and net long-term capital gains, would be taxable to Common Shareholders as ordinary income. Some portions of such distributions may be eligible for the dividends-received deduction in the case of corporate shareholders and may be eligible to be treated as “qualified dividend income” in the case of shareholders taxed as individuals, provided, in both cases, that the shareholder meets certain holding period and other requirements in respect of the Fund’s Common Shares (as described below). In addition, the Fund could be required to recognize unrealized gains, pay substantial taxes and interest and make substantial distributions before re-qualifying as a regulated investment company that is accorded special tax treatment.

The Fund intends to distribute to its shareholders, at least annually, all or substantially all of its investment company taxable income (computed without regard to the dividends-paid deduction), its net tax-exempt income (if any) and its net capital gain (that is, the excess of net long-term capital gain over net short-term capital loss, in each case determined with reference to any loss carryforwards). Any taxable income including any net capital gain retained by the Fund will be subject to tax at the Fund level at regular corporate rates. In the case of net capital gain, the Fund is permitted to designate the retained amount as undistributed capital gain in a timely notice to its shareholders who would then, in turn, (i) be required to include in income for U.S. federal income tax purposes, as long-term capital gain, their share of such undistributed amount, and (ii) be entitled to credit their proportionate shares of the tax paid by the Fund on such undistributed amount against their U.S. federal income tax liabilities, if any, and to claim refunds on a properly filed U.S. tax return to the extent the credit exceeds such liabilities. If the Fund makes this designation, for U.S. federal income tax purposes, the tax basis of Common Shares owned by a shareholder of the Fund will be increased by an amount equal to the difference between the amount of undistributed capital gains included in the shareholder’s gross income under clause (i) of the preceding sentence and the tax deemed paid by the shareholder under clause (ii) of the preceding sentence. The Fund is not required to, and there can be no assurance that the Fund will, make this designation if it retains all or a portion of its net capital gain in a taxable year.

As described under “Leverage” in the Prospectus, if at any time when Preferred Shares or other senior securities are outstanding the Fund does not meet applicable asset coverage requirements, it will be required to suspend distributions to Common Shareholders until the requisite asset coverage is restored. Any such suspension may cause the Fund to pay a U.S. federal income and excise tax on undistributed income or gains and may, in certain circumstances, prevent the Fund from being eligible for treatment as a regulated investment company. The Fund may repurchase, prepay or otherwise retire Preferred Shares or other senior securities, as applicable, in an effort to comply with the distribution requirement applicable to regulated investment companies.

Capital losses in excess of capital gains (“net capital losses”) are not permitted to be deducted against the Fund’s net investment income. Instead, potentially subject to certain limitations, the Fund may carry net capital losses from any taxable year forward to subsequent taxable years to offset capital gains, if any, realized during such subsequent taxable years. Capital loss carryforwards are reduced to the extent they offset current-year net realized capital gains, whether the Fund retains or distributes such gains. If the Fund incurs or has incurred net capital losses in taxable years beginning after December 22, 2010 (“post-2010 losses”), those losses will be carried forward to one or more subsequent taxable years without expiration. Any such carryforward losses will retain their character as short-term or long-term. If the Fund incurred net capital losses in a taxable year beginning on or before December 22, 2010 (“pre-2011 losses”), the Fund is permitted to carry such losses forward for eight taxable years; in the year to which they are carried forward, such losses are treated as short-term capital losses that first offset any short-term capital gains, and then offset any long-term capital gains. The Fund must use any post-2010 losses, which will not expire, before it uses any pre-2011 losses. This increases the likelihood that pre-2011 losses will expire unused at the conclusion of the eight-year carryforward period. The Fund’s available capital loss carryforwards, if any, will be set forth in its annual shareholder report for each fiscal year.

In determining its net capital gain, including in connection with determining the amount available to support a Capital Gain Dividend (as defined below), its taxable income and its earnings and profits, a regulated investment company generally may elect to treat part or all of any post-October capital loss (defined as any net capital loss attributable to the portion, if any, of the taxable year after October 31 or, if there is no such loss, the net long-term capital loss or net short-term capital loss attributable to such portion of the taxable year) or late-year ordinary loss (generally, the sum of its (i) net ordinary loss from the sale, exchange or other taxable disposition of property, attributable to the portion, if any, of the taxable year after October 31, and its (ii) other net ordinary loss attributable to the portion, if any, of the taxable year after December 31) as if incurred in the succeeding taxable year.

If the Fund were to fail to distribute in a calendar year at least an amount equal to the sum of 98% of its ordinary income for such year and 98.2% of its capital gain net income recognized for the one-year period ending on October 31 of such year (or November 30 or December 31 of that year if the Fund is permitted to elect and so elects), plus any such amounts retained from the prior year, the Fund would be subject to a nondeductible 4% excise tax on the undistributed amounts. For purposes of the required excise tax distribution, a regulated investment company’s ordinary gains and losses from the sale, exchange, or other taxable disposition of property that would otherwise be taken into account after October 31 (or November 30 of that year if the regulated investment company makes the election described above) generally are treated as arising on January 1 of the following calendar year; in the case of a regulated investment company with a December 31 year end that makes the election described above, no such gains or losses will be so treated. Also, for these purposes, the Fund will be treated as having distributed any amount on which it is subject to corporate income tax for the taxable year ending within the calendar year. The Fund intends generally to make distributions sufficient to avoid imposition of the 4% excise tax, although there can be no assurance that it will be able to or will do so.

The Fund intends to make monthly distributions. Unless a shareholder elects otherwise, all distributions will be automatically reinvested in additional Common Shares of the Fund pursuant to the Fund’s Dividend Reinvestment Plan (see “Dividend Reinvestment Plan” in the Prospectus). A shareholder whose distributions are reinvested in Common Shares under the Dividend Reinvestment Plan will be treated for U.S. federal income tax purposes as having received an amount in distribution equal to either (i) if newly issued Common Shares are issued under the Dividend Reinvestment Plan, generally the fair market value of the newly issued Common Shares issued to the shareholder or (ii) if reinvestment is made through open-market purchases under the Dividend Reinvestment Plan, the amount of cash allocated to the shareholder for the purchase of Common Shares on its behalf in the open market. For U.S. federal income tax purposes, all distributions are generally taxable in the manner described below, whether a shareholder takes them in cash or they are reinvested pursuant to the Dividend Reinvestment Plan in additional shares of the Fund.

Fund distributions generally will be taxable to shareholders in the calendar year in which the distributions are declared, rather than the calendar year in which the distributions are received. See the discussion below regarding distributions declared in October, November or December for further information. Distributions received by tax-exempt shareholders generally will not be subject to U.S. federal income tax to the extent permitted under applicable tax law.

For U.S. federal income tax purposes, distributions of investment income are generally taxable as ordinary income. Taxes on distributions of capital gains are determined by how long the Fund owned (or is deemed to have owned) the investments that generated the gains, rather than how long a shareholder has owned his or her Common Shares. In general, the Fund will recognize long-term capital gain or loss on investments it has owned (or is deemed to have owned) for more than one year, and short-term capital gain or loss on investments it has owned (or is deemed to have owned) for one year or less. Tax rules can alter the Fund’s holding period in investments and thereby affect the tax treatment of gain or loss in respect of such investments. Distributions of net capital gain that are properly reported by the Fund as capital gain dividends (“Capital Gain Dividends”) will be taxable to shareholders as long-term capital gains includible in net capital gain and taxed to individuals at reduced rates relative to ordinary income. Distributions of net short-term capital gain (as reduced by any net long-term capital loss for the taxable year) will be taxable to shareholders as ordinary income.

Distributions of investment income reported by the Fund as derived from “qualified dividend income” will be taxed in the hands of individuals at the rates applicable to net capital gain, provided holding period and other requirements are met at both the shareholder and Fund levels. The Fund does not expect a significant portion of distributions to be derived from qualified dividend income.

In general, dividends of net investment income received by corporate shareholders of the Fund will qualify for the dividends-received deduction generally available to corporations only to the extent of the amount of eligible dividends received by the Fund from domestic corporations for the taxable year if certain holding period and other requirements are met at both the shareholder and Fund levels. The Fund does not expect a significant portion of distributions to be eligible for the dividends-received deduction.

Any distribution of income that is attributable to (i) income received by the Fund in lieu of dividends with respect to securities on loan pursuant to a securities lending transaction or (ii) dividend income received by the Fund on securities it temporarily purchased from a counterparty pursuant to a repurchase agreement that is treated for U.S. federal income tax purposes as a loan by the Fund, will not constitute qualified dividend income to non-corporate shareholders and will not be eligible for the dividends-received deduction for corporate shareholders.

The IRS currently requires a regulated investment company that the IRS recognizes as having two or more “classes” of stock for U.S. federal income tax purposes to allocate to each such class proportionate amounts of each type of its income (such as ordinary income and capital gains) based upon the percentage of total dividends distributed to each class for the tax year. Accordingly, as applicable, the Fund intends each tax year to allocate Capital Gain Dividends for each tax year between and among its Common Shares and each series of its Preferred Shares in proportion to the total dividends paid to each class with respect to such tax year. Dividends qualifying for the dividends received deduction or as qualified dividend income will be allocated between and among Common Shares and each series of Preferred Shares separately from dividends that do not so qualify, in each case in proportion to the total dividends paid to each share class for the Fund’s tax year.

The Code generally imposes a 3.8% Medicare contribution tax on the net investment income of certain individuals, trusts and estates to the extent their income exceeds certain threshold amounts. For these purposes, “net investment income” generally includes, among other things, (i) distributions paid by the Fund of net investment income and capital gains as described above, and

(ii) any net gain from the sale, exchange or other taxable disposition of Fund shares. Common Shareholders are advised to consult their tax advisors regarding the possible implications of this additional tax on their investment in the Fund.

If, in and with respect to any taxable year, the Fund makes a distribution in excess of its current and accumulated “earnings and profits,” the excess distribution will be treated as a return of capital to the extent of a shareholder’s tax basis in his or her Common Shares, and thereafter as capital gain. A return of capital is not taxable, but it reduces a shareholder’s basis in his or her shares, thus reducing any loss or increasing any gain on a subsequent taxable disposition by the shareholder of such shares. Where one or more such distributions occur in and with respect to any taxable year of the Fund, the available earnings and profits will be allocated first to the distributions made to the holders of Preferred Shares, and only thereafter to distributions made to holders of Common Shares. As a result, the holders of Preferred Shares will receive a disproportionate share of the distributions, if any, treated as dividends, and the holders of the Common Shares will receive a disproportionate share of the distributions, if any, treated as a return of capital.

A distribution by the Fund will be treated as paid on December 31 of any calendar year if it is declared by the Fund in October, November or December with a record date in such a month and paid by the Fund during January of the following calendar year. Such distributions will be taxable to shareholders in the calendar year in which the distributions are declared, rather than the calendar year in which the distributions are received.

As required by federal law, detailed federal tax information with respect to each calendar year will be furnished to shareholders early in the succeeding year.

Dividends and distributions on Common Shares are generally subject to U.S. federal income tax as described herein to the extent they do not exceed the Fund’s realized income and gains, even though such dividends and distributions may economically represent a return of a particular shareholder’s investment. Such distributions are likely to occur in respect of Common Shares purchased at a time when the Fund’s net asset value reflects unrealized gains or income or gains that are realized but not yet distributed. Such realized income and gains may be required to be distributed even when the Fund’s net asset value also reflects unrealized losses.

If the Fund holds, directly or indirectly, one or more Build America Bonds issued before January 1, 2011, or other tax credit bonds issued on or before December 31, 2017, on one or more applicable dates during a taxable year, it is possible that the Fund will elect to permit its shareholders to claim a tax credit on their income tax returns equal to each shareholder’s proportionate share of tax credits from the applicable bonds that otherwise would be allowed to the Fund. In such a case, a shareholder will be deemed to receive a distribution of money with respect to its Fund shares equal to the shareholder’s proportionate share of the amount of such credits and be allowed a credit against the shareholder’s U.S. federal income tax liability equal to the amount of such deemed distribution, subject to certain limitations imposed by the Code on the credits involved. Even if the Fund is eligible to pass through tax credits to shareholders, the Fund may choose not to do so.

The sale, exchange or repurchase of Fund shares may give rise to a gain or loss. In general, any gain or loss realized upon a taxable disposition of Fund shares treated as a sale or exchange for U.S. federal income tax purposes will be treated as long-term capital gain or loss if the shares have been

held for more than 12 months. Otherwise, such gain or loss on the taxable disposition of Fund shares will be treated as short-term capital gain or loss. However, any loss realized upon a taxable disposition of Fund shares held for six months or less (i) will be treated as long-term, rather than short-term, to the extent of any long-term capital gain distributions received (or deemed received) by the shareholder with respect to the shares and (ii) generally will be disallowed to the extent of any exempt-interest dividends received by the shareholder with respect to the shares.

All or a portion of any loss realized upon a taxable disposition of Fund shares will be disallowed under the Code’s “wash sale” rule if other substantially identical shares of the Fund are purchased within 30 days before or after the disposition. In such a case, the basis of the newly purchased shares will be adjusted to reflect the disallowed loss.

In the event that the Fund repurchases a shareholder’s Common Shares (as described in the Prospectus), such repurchase generally will be treated as a sale or exchange of the shares by a shareholder provided that either (i) the shareholder tenders, and the Fund repurchases, all of such shareholder’s shares (and such shareholder does not hold and is not deemed to hold any Preferred Shares), thereby reducing the shareholder’s percentage ownership of the Fund, whether directly or by attribution under Section 318 of the Code, to 0%, (ii) the shareholder meets numerical safe harbors under the Code with respect to percentage voting interest and reduction in ownership of the Fund following completion of the tender offer, or (iii) the tender offer otherwise results in a “meaningful reduction” of the shareholder’s ownership percentage interest in the Fund, which determination depends on a particular shareholder’s facts and circumstances.

If a tendering shareholder’s proportionate ownership of the Fund (determined after applying the ownership attribution rules under Section 318 of the Code) is not reduced to the extent required under the tests described above, such shareholder will be deemed to receive a distribution from the Fund under Section 301 of the Code with respect to the shares held (or deemed held under Section 318 of the Code) by the shareholder after the tender offer (a “Section 301 distribution”). The amount of this distribution will equal the price paid by the Fund to such shareholder for the shares sold, and will be taxable as a dividend, i.e., as ordinary income, to the extent of the Fund’s current or accumulated earnings and profits allocable to such distribution, with the excess treated as a return of capital reducing the shareholder’s tax basis in the shares held after the tender offer, and thereafter as capital gain. In the event a repurchase is treated as a Section 301 distribution, any Fund shares held by a shareholder thereafter will be subject to basis adjustments in accordance with the provisions of the Code.

Provided that no tendering shareholder is treated as receiving a Section 301 distribution as a result of selling Common Shares pursuant to a particular tender offer, shareholders who do not sell shares pursuant to that tender offer will not realize constructive distributions on their shares as a result of other shareholders selling shares in the tender offer. In the event that any tendering shareholder is deemed to receive a Section 301 distribution, it is possible that shareholders whose proportionate ownership of the Fund increases as a result of that tender offer, including shareholders who do not tender any shares, will be deemed to receive a constructive distribution under Section 305(c) of the Code in an amount equal to the increase in their percentage ownership of the Fund as a result of the tender offer. Such constructive distribution will be treated as a dividend to the extent of current or accumulated earnings and profits allocable to it.

Use of the Fund’s cash to repurchase shares may adversely affect the Fund’s ability to satisfy the distribution requirements for treatment as a regulated investment company described above. The Fund may also recognize income in connection with the sale of portfolio securities to fund share purchases, in which case the Fund would take any such income into account in determining whether such distribution requirements have been satisfied.

If the Fund were to repurchase Common Shares on the open market, such repurchase would similarly result in a percentage increase in the interests of remaining shareholders. In such a case, a selling shareholder would likely have no specific knowledge that he or she is selling his or her shares to the Fund. It is therefore less likely that shareholders whose percentage share interests in the Fund increase as a result of any such open-market sale will be treated as having received a taxable distribution from the Fund.

The foregoing discussion does not address the tax treatment of tendering shareholders who do not hold their shares as a capital asset. Such shareholders should consult their own tax advisors on the specific tax consequences to them of participating or not participating in the tender offer.

A portion of the interest paid or accrued on certain high yield discount obligations owned by the Fund may not, and interest paid on debt obligations, if any, that are considered for tax purposes to be payable in the equity of the issuer or a related party will not be deductible to the issuer. This may affect the cash flow of the issuer. If a portion of the interest paid or accrued on certain high yield discount obligations is not deductible, that portion will be treated as a dividend paid by the issuer for purposes of the corporate dividends received deduction. In such cases, if the issuer of the high yield discount obligations is a domestic corporation, dividend payments by the Fund may be eligible for the dividends-received deduction to the extent attributable to the deemed dividend portion of such accrued interest.

Original Issue Discount, Payment-in-Kind Securities, Market Discount, Preferred Securities, and Commodity-Linked Notes

Some debt obligations with a fixed maturity date of more than one year from the date of issuance (and zero-coupon debt obligations with a fixed maturity date of more than one year from the date of issuance) will be treated as debt obligations that are issued originally at a discount. Generally, the amount of the original issue discount (“OID”) is treated as interest income and is included in the Fund’s income and required to be distributed over the term of the debt obligation, even though payment of that amount is not received until a later time, upon partial or full repayment or disposition of the debt obligation. Increases in the principal amount of an inflation-indexed bond will generally be treated as OID.

Some debt obligations with a fixed maturity date of more than one year from the date of issuance that are acquired by the Fund in the secondary market may be treated as having “market discount.” Very generally, market discount is the excess of the stated redemption price of a debt obligation (or in the case of an obligation issued with OID, its “revised issue price”) over the purchase price of such obligation. Subject to the discussion below regarding Section 451 of the Code, (i) generally, any gain recognized on the disposition of, and any partial payment of principal on, a debt obligation having market discount is treated as ordinary income to the extent the gain, or principal payment, does not exceed the “accrued market discount” on such debt obligation, (ii) alternatively, the Fund may elect to accrue market discount currently, in which case the Fund will be required to include the accrued market discount on such debt obligations in the Fund’s income (as ordinary income)

and thus distribute it over the term of the debt obligations, even though payment of that amount is not received until a later time, upon partial or full repayment or disposition of the debt obligations, and (iii) the rate at which the market discount accrues, and thus is included in the Fund’s income, will depend upon which of the permitted accrual methods the Fund elects. The Fund reserves the right to revoke such an election at any time pursuant to applicable IRS procedures. Notwithstanding the foregoing, effective for taxable years beginning after 2017, Section 451 of the Code generally requires any accrual method taxpayer to take into account items of gross income no later than the time at which such items are taken into account as revenue in the taxpayer’s financial statements. The application of Section 451 to the accrual of market discount is currently unclear. If Section 451 applies to the accrual of market discount, the Fund must include in income any market discount as it takes the same into account on its financial statements. In the case of higher-risk securities, the amount of market discount may be unclear. See “Higher-Risk Securities.”

From time to time, a substantial portion of the Fund’s investments in loans and other debt obligations could be treated as having OID and/or market discount, which, in some cases could be significant. To generate sufficient cash to make the requisite distributions, the Fund may be required to sell securities in its portfolio (including when it is not advantageous to do so) that it otherwise would have continued to hold.

A portion of the OID accrued on certain high yield discount obligations may not be deductible to the issuer and will instead be treated as a dividend paid by the issuer for purposes of the dividends-received deduction. In such cases, if the issuer of the high yield discount obligations is a domestic corporation, dividend payments by the Fund may be eligible for the dividends-received deduction to the extent attributable to the deemed dividend portion of such OID.

Some debt obligations with a fixed maturity date of one year or less from the date of issuance may be treated as having OID or, in certain cases, “acquisition discount” (very generally, the excess of the stated redemption price over the purchase price). The Fund will be required to include the OID or acquisition discount in income (as ordinary income) and thus distribute it over the term of the debt obligation, even though payment of that amount is not received until a later time, upon partial or full repayment or disposition of the debt obligation. The rate at which OID or acquisition discount accrues, and thus is included in the Fund’s income, will depend upon which of the permitted accrual methods the Fund elects.

Some preferred securities may include provisions that permit the issuer, at its discretion, to defer the payment of distributions for a stated period without any adverse consequences to the issuer.

If the Fund owns a preferred security that is deferring the payment of its distributions, the Fund may be required to report income for U.S. federal income tax purposes to the extent of any such deferred distributions even though the Fund has not yet actually received the cash distribution.

In addition, pay-in-kind obligations will, and commodity-linked notes may, give rise to income which is required to be distributed and is taxable even though the Fund receives no interest payment in cash on the security during the year.

If the Fund holds the foregoing kinds of obligations, or other obligations subject to special rules under the Code, the Fund may be required to pay out as an income distribution each year an amount which is greater than the total amount of cash interest the Fund actually received. Such distributions may be made from the cash assets of the Fund or by liquidation of portfolio securities, if necessary

(including when it is not advantageous to do so). The Fund may realize gains or losses from such liquidations, including short-term capital gains taxable as ordinary income. In the event the Fund realizes net capital gains from such transactions, its shareholders may receive a larger capital gain distribution than they might otherwise receive in the absence of such transactions.

The Fund may invest in debt obligations that are in the lowest rating categories or are unrated, including debt obligations of issuers not currently paying interest or who are in default. Investments in debt obligations that are at risk of or in default present special tax issues for the Fund. Tax rules are not entirely clear about issues such as whether or to what extent the Fund should recognize market discount on a debt obligation, when the Fund may cease to accrue interest, OID or market discount, when and to what extent the Fund may take deductions for bad debts or worthless securities and how the Fund should allocate payments received on obligations in default between principal and income. These and other related issues will be addressed by the Fund when, as and if it invests in such securities, in order to seek to ensure that it distributes sufficient income to preserve its status as a regulated investment company and does not become subject to federal income or excise tax.

Very generally, where the Fund purchases a bond at a price that exceeds the redemption price at maturity—i.e., at a premium—the premium is amortizable over the remaining term of the bond. In the case of a taxable bond, if the Fund makes an election applicable to all such bonds it purchases, which election is irrevocable without consent of the IRS, the Fund reduces the current taxable income from the bond by the amortized premium and reduces its tax basis in the bond by the amount of such offset; upon the disposition or maturity of such bonds acquired on or after January 4, 2013, the Fund is permitted to deduct any remaining premium allocable to a prior period. In the case of a tax-exempt bond, tax rules require the Fund to reduce its tax basis by the amount of amortized premium.

The proper tax treatment of income or loss realized by the retirement or sale of certain catastrophe bonds is unclear. The Fund will report such income or loss as capital or ordinary income or loss in a manner consistent with any IRS position on the subject following the publication of such a position.

Equity investments by the Fund in certain “passive foreign investment companies” (“PFICs”) could subject the Fund to a U.S. federal income tax (including interest charges) on distributions received from the PFIC or on proceeds received from the disposition of shares in the PFIC. This tax cannot be eliminated by making distributions to Fund shareholders. However, the Fund may elect to treat a PFIC as a “qualified electing fund” (i.e., make a “QEF election”), in which case the Fund will be required to include its share of the company’s income and net capital gains annually, regardless of whether it receives any distribution from the company. Under proposed Treasury regulations, any such income or net capital gain of the PFIC that is required to be included in the Fund’s gross income would be qualifying income to the extent that the PFIC timely distributes to the Fund an amount at least equal to such inclusion. If the PFIC were to fail to make such a distribution or

distributions, the failure could adversely affect the Fund’s ability to qualify as a regulated investment company. The Fund also may make an election to mark the gains (and to a limited extent losses) in such holdings “to the market” as though it had sold and repurchased its holdings in those PFICs on the last day of the Fund’s taxable year. Such gains and losses are treated as ordinary income and loss. The QEF and mark-to-market elections may accelerate the recognition of income (without the receipt of cash) and increase the amount required to be distributed by the Fund to avoid taxation. Making either of these elections therefore may require the Fund to sell other investments (including when it is not advantageous to do so) to meet its distribution requirement, which also may accelerate the recognition of gain and affect the Fund’s total return. Because it is not always possible to identify a foreign corporation as a PFIC, the Fund may incur the tax and interest charges described above in some instances. Dividends paid by PFICs will not be eligible to be treated as “qualified dividend income.”

The interest on municipal bonds is generally exempt from U.S. federal income tax. The Fund does not expect to invest 50% or more of its assets in municipal bonds on which the interest is exempt from U.S. federal income tax, or in interests in other regulated investment companies. As a result, it does not expect to be eligible to pay “exempt-interest dividends” to its shareholders under the applicable tax rules. As a result, interest on municipal bonds is taxable to shareholders of the Fund when received as a distribution from the Fund. In addition, gains realized by the Fund on the sale or exchange of municipal bonds are taxable to shareholders of the Fund when distributed to shareholders.

Any investment by the Fund in equity securities of REITs may result in the Fund’s receipt of cash in excess of the REIT’s earnings; if the Fund distributes these amounts, these distributions could constitute a return of capital to Fund shareholders for U.S. federal income tax purposes. Investments in REIT equity securities also may require the Fund to accrue and to distribute income not yet received. To generate sufficient cash to make the requisite distributions, the Fund may be required to sell securities in its portfolio (including when it is not advantageous to do so) that it otherwise would have continued to hold. Dividends received by the Fund from a REIT generally will not constitute qualified dividend income.

The Fund’s transactions in foreign currencies, foreign currency-denominated debt obligations and certain foreign currency options, futures contracts and forward contracts (and similar instruments) may give rise to ordinary income or loss to the extent such income or loss results from fluctuations in the value of the foreign currency concerned. Any such net gains could require a larger dividend toward the end of the calendar year. Any such net losses will generally reduce and potentially require the recharacterization of prior ordinary income distributions and may accelerate Fund distributions to shareholders and increase the distributions taxed to shareholders as ordinary income. Any net ordinary losses so created cannot be carried forward by the Fund to offset income or gains earned in subsequent taxable years.

Options, Futures, and Forward Contracts, Swap Agreements, and other Derivatives

In general, option premiums received by the Fund are not immediately included in the income of the Fund. Instead, the premiums are recognized when the option contract expires, the option is exercised by the holder, or the Fund transfers or otherwise terminates the option (e.g. through a closing transaction). If a call option written by the Fund is exercised and the Fund sells or delivers the underlying stock, the Fund generally will recognize capital gain or loss equal to (a) the sum of the strike price and the option premium received by the Fund minus (b) the Fund’s basis in the stock. Such gain or loss generally will be short-term or long-term depending upon the holding period of the underlying stock. If securities are purchased by the Fund pursuant to the exercise of a put option written by it, the Fund will generally subtract the premium received for purposes of computing its cost basis in the stock purchased. Gain or loss arising in respect of a termination of the Fund’s obligation under an option other than through the exercise of the option will be short-term capital gain or loss depending on whether the premium income received by the Fund is greater or less than the amount paid by the Fund (if any) in terminating the transaction. Thus, for example, if an option written by the Fund expires unexercised, the Fund generally will recognize short-term capital gain equal to the premium received.

The Fund’s options activities may include transactions constituting straddles for U.S. federal income tax purposes, that is, that trigger the U.S. federal income tax straddle rules contained primarily in Section 1092 of the Code. Such straddles include, for example, positions in a particular security, or an index of securities, and one or more options that offset the former position, including options that are “covered” by the Fund’s long position in the subject security. Very generally, where applicable, Section 1092 requires (i) that losses be deferred on positions deemed to be offsetting positions with respect to “substantially similar or related property” to the extent of unrealized gain in the latter, and (ii) that the holding period of such a straddle position that has not already been held for the long-term holding period be terminated and begin anew once the position is no longer part of a straddle. Options on single stocks that are not “deep in the money” may constitute qualified covered calls, which generally are not subject to the straddle rules; the holding period on stock underlying qualified covered calls that are “in the money” although not “deep in the money” will be suspended during the period that such calls are outstanding. Thus, the straddle rules and the rules governing qualified covered calls could cause gains that would otherwise constitute long-term capital gains to be treated as short-term capital gains, and distributions that would otherwise constitute “qualified dividend income” or qualify for the dividends-received deduction to fail to satisfy the holding period requirements and therefore to be taxed as ordinary income or to fail to qualify for the dividends received deduction, as the case may be.

The tax treatment of certain positions entered into by the Fund, including regulated futures contracts, certain foreign currency positions and certain listed non-equity options, will be governed by section 1256 of the Code (“section 1256 contracts”). Gains or losses on section

1256 contracts generally are considered 60% long-term and 40% short-term capital gains or losses (“60/40”), although certain foreign currency gains and losses from such contracts may be treated as ordinary in character. Also, section 1256 contracts held by the Fund at the end of each taxable year (and, for purposes of the 4% excise tax, on certain other dates as prescribed under the Code) are “marked to market” with the result that unrealized gains or losses are treated as though they were realized and the resulting gain or loss is treated as ordinary or 60/40 gain or loss, as applicable.

In addition to the special rules described above in respect of futures and options transactions, the Fund’s transactions in other derivatives instruments (e.g., forward contracts and swap agreements), as well as any of its hedging, short sale, securities loan or similar transactions may be subject to one or more special tax rules (e.g., notional principal contract, straddle, constructive sale, straddle, wash sale and short sale rules). These rules may affect whether gains and losses recognized by the Fund are treated as ordinary or capital, accelerate the recognition of income or gains to the Fund, defer losses to the Fund, and cause adjustments in the holding periods of the Fund’s securities, thereby affecting, among other things, whether capital gains and losses are treated as short-term or long-term. These rules could, therefore, affect the amount, timing and/or character of distributions to shareholders.

Because these and other tax rules applicable to these types of transactions are in some cases uncertain under current law, an adverse determination or future guidance by the IRS with respect to these rules (which determination or guidance could be retroactive) may affect whether the Fund has made sufficient distributions, and otherwise satisfied the relevant requirements, to maintain its qualification as a regulated investment company and avoid a Fund-level tax.

The Fund’s investments in commodities and commodity-linked instruments, if any, will potentially be limited by the Fund’s intention to qualify as a regulated investment company, and will potentially limit the Fund’s ability to so qualify. Income and gains from commodities and certain commodity-linked instruments do not constitute qualifying income to a regulated investment company for purposes of the 90% gross income test described above. In addition, the tax treatment of some other commodity-linked instruments in which the Fund might invest is not certain, in particular with respect to whether income or gains from such instruments constitute qualifying income to a regulated investment company. If the Fund were to treat income or gain from a particular instrument as qualifying income and the income or gain were later determined not to constitute qualifying income, and, together with any other nonqualifying income, caused the Fund’s nonqualifying income to exceed 10% of its gross income in any taxable year, the Fund would fail to qualify as a regulated investment company unless it is eligible to and does pay a tax at the Fund level.

Certain of the Fund’s investments in derivative instruments and foreign currency-denominated instruments, and any of the Fund’s transactions in foreign currencies and hedging activities, are likely to produce a difference between its book income and the sum of its taxable income and net tax-exempt income (if any). If such a difference arises, and the Fund’s book income is less than the sum of its taxable income and net tax-exempt income (if any), the Fund could be required to make distributions exceeding book income to qualify as a regulated investment company that is accorded special tax treatment and to avoid an entity-level tax. In the alternative, if the Fund’s book income exceeds the sum of its taxable income (including realized capital gains) and net tax-exempt income (if any), the distribution (if any) of such excess generally will be treated as (i) a dividend to the extent of the Fund’s remaining earnings and profits, (ii) thereafter, as a return of capital to the extent of the recipient’s basis in its shares and (iii) thereafter, as gain from the sale or exchange of a capital asset.

If the Fund participates in a short sale and, on the date of such short sale, the Fund either (i) does not hold securities substantially identical to those sold short or (ii) has held such substantially identical securities for one year or less, the character of gain or loss realized on such a short sale generally will be short-term. If the Fund participates in a short sale and, on the date of such short sale, the Fund has held substantially identical securities for more than one year, the character of gain realized on such short sale will be determined by reference to the Fund’s holding period in the property actually used to close the short sale; the character of loss realized on such short sale generally will be long term, regardless of the holding period of the securities actually used to close such short sale. Because net short-term capital gain (after reduction by any long-term capital loss) is generally taxed at ordinary income rates, the Fund’s short sale transactions can increase the percentage of the Fund’s gains that are taxable to shareholders as ordinary income.

The Fund may invest directly or indirectly in real estate mortgage investment conduits (“REMICs”) (including by investing in residual interests in CMOs with respect to which an election to be treated as a REMIC is in effect) or equity interests in taxable mortgage pools (“TMPs”). Under a notice issued by the IRS in October 2006 and Treasury regulations that have yet to be issued but may apply retroactively, a portion of the Fund’s income (including income allocated to the Fund from a REIT or other pass-through entity) that is attributable to a residual interest in a REMIC or an equity interest in a TMP — referred to in the Code as an “excess inclusion”— will be subject to U.S. federal income tax in all events. This notice also provides, and the regulations are expected to provide, that “excess inclusion income” of a regulated investment company, such as the Fund, will be allocated to shareholders of the regulated investment company in proportion to the dividends received by such shareholders, with the same consequences as if the shareholders held the related interest directly. As a result, the Fund may not be a suitable investment for charitable remainder trusts, as noted below.

In general, excess inclusion income allocated to shareholders (i) cannot be offset by net operating losses (subject to a limited exception for certain thrift institutions), (ii) will constitute unrelated business taxable income (“UBTI”) to entities (including a qualified pension plan, an individual retirement account, a 401(k) plan, a Keogh plan or other tax-exempt entity) subject to tax on UBTI, thereby potentially requiring such an entity that is allocated excess inclusion income, and otherwise might not be required to file a U.S. federal income tax return, to file such a tax return and pay tax on such income and (iii) in the case of a non-U.S. shareholder, will not qualify for any reduction in U.S. federal withholding tax. A shareholder will be subject to U.S. federal income tax on such inclusions notwithstanding any exemption from such income tax otherwise available under the Code.

Income, proceeds and gains received by the Fund from sources within foreign countries may be subject to withholding and other taxes imposed by such countries, which will reduce the return on those investments. Tax treaties between certain countries and the United States may reduce or eliminate such taxes.

If, at the close of its taxable year, more than 50% of the value of the Fund’s total assets consists of securities of foreign corporations, including for this purpose foreign governments, the Fund will be permitted to make an election under the Code that will allow shareholders a deduction or credit for

foreign taxes paid by the Fund. In such a case, shareholders will include in gross income from foreign sources their pro rata shares of such taxes. A shareholder’s ability to claim an offsetting foreign tax credit or deduction in respect of such foreign taxes is subject to certain limitations imposed by the Code, which may result in the shareholder’s not receiving a full credit or deduction (if any) for the amount of such taxes. Shareholders who do not itemize on their U.S. federal income tax returns may claim a credit (but not a deduction) for such foreign taxes. If the Fund does not qualify for or chooses not to make such an election, shareholders will not be entitled separately to claim a credit or deduction for U.S. federal income tax purposes with respect to foreign taxes paid by the Fund; in that case the foreign tax will nonetheless reduce the Fund’s taxable income. Even if the Fund elects to pass through to its shareholders foreign tax credits or deductions, tax-exempt shareholders and those who invest in the Fund through tax-advantaged accounts such as IRAs will not benefit from any such tax credit or deduction.

Income of a regulated investment company that would be UBTI if earned directly by a tax-exempt entity will not generally be attributed as UBTI to a tax-exempt shareholder of the regulated investment company. Notwithstanding this “blocking” effect, a tax-exempt shareholder could realize UBTI by virtue of its investment in the Fund if shares in the Fund constitute debt-financed property in the hands of the tax-exempt shareholder within the meaning of Code Section 514(b). A tax-exempt shareholder may also recognize UBTI if the Fund recognizes “excess inclusion income” derived from direct or indirect investments in residual interests in REMICs or equity interests in TMPs as described above, if the amount of such income recognized by the Fund exceeds the Fund’s investment company taxable income (after taking into account deductions for dividends paid by the Fund).

In addition, special tax consequences apply to charitable remainder trusts (“CRTs”) that invest in regulated investment companies that invest directly or indirectly in residual interests in REMICs or equity interests in TMPs. Under legislation enacted in December 2006, if a charitable remainder trust (“CRT”), as defined in Section 664 of the Code, realizes any UBTI for a taxable year, a 100% excise tax is imposed on such UBTI. Under IRS guidance issued in October 2006, a CRT will not recognize UBTI solely as a result of investing in a regulated investment company that recognizes “excess inclusion income.” Rather, if at any time during any taxable year a CRT (or one of certain other tax-exempt shareholders, such as the United States, a state or political subdivision, or an agency or instrumentality thereof, and certain energy cooperatives) is a record holder of a share in a regulated investment company that recognizes “excess inclusion income,” then the regulated investment company will be subject to a tax on that portion of its “excess inclusion income” for the taxable year that is allocable to such shareholders at the highest federal corporate income tax rate. The extent to which this IRS guidance remains applicable in light of the December 2006 legislation is unclear. To the extent permitted under the 1940 Act, the Fund may elect to specially allocate any such tax to the applicable CRT, or other shareholder, and thus reduce such shareholder’s distributions for the year by the amount of the tax that relates to such shareholder’s interest in the Fund. CRTs and other tax-exempt shareholders are urged to consult their tax advisors concerning the consequences of investing in the Fund.

Distributions by the Fund to shareholders that are not “United States persons” within the meaning of the Code (“foreign shareholders”) properly reported by the Fund as (1) Capital Gain Dividends, (2) short-term capital gain dividends, or (3) interest-related dividends, each as defined and subject to certain conditions described below generally are not subject to withholding of U.S. federal income tax.

In general, the Code defines (1) “short-term capital gain dividends” as distributions of net short-term capital gains in excess of net long-term capital losses and (2) “interest-related dividends” as distributions from U.S. source interest income of types similar to those not subject to U.S. federal income tax if earned directly by an individual foreign shareholder, in each case to the extent such distributions are properly reported as such by the Fund in a written notice to shareholders. The exceptions to withholding for Capital Gain Dividends and short-term capital gain dividends do not apply to (A) distributions to an individual foreign shareholder who is present in the United States for a period or periods aggregating 183 days or more during the year of the distribution and (B) distributions attributable to gain that is effectively connected with the conduct by the foreign shareholder of a trade or business within the United States under special rules regarding the disposition of U.S. real property interests as described below. If the Fund invests in a regulated investment company that pays such distributions to the Fund, such distributions retain their character as not subject to withholding if properly reported when paid by the Fund to foreign shareholders. The exception to withholding for interest-related dividends does not apply to distributions to a foreign shareholder (A) that has not provided a satisfactory statement that the beneficial owner is not a United States person, (B) to the extent that the dividend is attributable to certain interest on an obligation if the foreign shareholder is the issuer or is a 10% shareholder of the issuer, (C) that is within certain foreign countries that have inadequate information exchange with the United States, or (D) to the extent the dividend is attributable to interest paid by a person that is a related person of the foreign shareholder and the foreign shareholder is a controlled foreign corporation.

The Fund is permitted to report such part of its dividends as interest-related or short-term capital gain dividends as are eligible, but is not required to do so. In the case of shares held through an intermediary, the intermediary may withhold even if the Fund reports all or a portion of a payment as an interest-related or short-term capital gain dividend to shareholders. Foreign shareholders should contact their intermediaries regarding the application of withholding rules to their accounts.

Distributions by the Fund to foreign shareholders other than Capital Gain Dividends, short-term capital gain dividends, and interest-related dividends (e.g., dividends attributable to dividend and foreign-source interest income or to short-term capital gains or U.S. source interest income to which the exception from withholding described above does not apply) are generally subject to withholding of U.S. federal income tax at a rate of 30% (or lower applicable treaty rate).

A foreign shareholder is not, in general, subject to U.S. federal income tax on gains (and is not allowed a deduction for losses) realized on the sale of shares of the Fund unless (i) such gain is effectively connected with the conduct by the foreign shareholder of a trade or business within the United States, (ii) in the case of a foreign shareholder that is an individual, the shareholder is present in the United States for a period or periods aggregating 183 days or more during the year of the sale and certain other conditions are met, or (iii) the special rules relating to gain attributable to the sale or exchange of “U.S. real property interests” (“USRPIs”) apply to the foreign shareholder’s sale of shares of the Fund (as described below).

Foreign shareholders with respect to whom income from the Fund is effectively connected with a trade or business conducted by the foreign shareholder within the United States will in general be subject to U.S. federal income tax on the income derived from the Fund at the graduated rates applicable to U.S. citizens, residents or domestic corporations, whether such income is received in cash or reinvested in shares of the Fund and, in the case of a foreign corporation, may also be subject to a branch profits tax. If a foreign shareholder is eligible for the benefits of a tax treaty, any effectively connected income or gain will generally be subject to U.S. federal income tax on a net basis only if it is also attributable to a permanent establishment maintained by the shareholder in the United States. More generally, foreign shareholders who are residents in a country with an income tax treaty with the United States may obtain different tax results than those described herein, and are urged to consult their tax advisors.

Special rules would apply if the Fund were a qualified investment entity (“QIE”) because it is either a “U.S. real property holding corporation” (“USRPHC”) or would be a USRPHC but for the operation of certain exceptions to the definition thereof. Very generally, a USRPHC is a domestic corporation that holds USRPIs the fair market value of which equals or exceeds 50% of the sum of the fair market values of the corporation’s USRPIs, interests in real property located outside the United States, and other trade or business assets. USRPIs are generally defined as any interest in U.S. real property and any interest (other than solely as a creditor) in a USRPHC or, very generally, an entity that has been a USRPHC in the last five years. A regulated investment company that holds, directly or indirectly, significant interests in REITs may be a USRPHC. Interests in domestically controlled QIEs, including REITs and regulated investment companies that are QIEs, not-greater-than-10% interests in publicly traded classes of stock in REITs and not-greater-than-5% interests in publicly traded classes of stock in regulated investment companies generally are not USRPIs, but these exceptions do not apply for purposes of determining whether the Fund is a QIE.

If an interest in the Fund were a USRPI, the Fund would be required to withhold U.S. tax on the proceeds of a share redemption by a greater-than-5% foreign shareholder or any foreign shareholder if shares of the Fund are not considered regularly traded on an established securities market, in which case such foreign shareholder generally would also be required to file a U.S. tax return and pay any additional taxes due in connection with the redemption.

If the Fund were a QIE, under a special “look-through” rule, any distributions by the Fund to a foreign shareholder (including, in certain cases, distributions made by the Fund in redemption of its shares) attributable directly or indirectly to (i) distributions received by the Fund from a lower-tier regulated investment company or REIT that the Fund is required to treat as USRPI gain in its hands, or (ii) gains realized by the Fund on the disposition of USRPIs would retain their character as gains realized from USRPIs in the hands of the Fund’s foreign shareholders, and would be subject to U.S. withholding tax. In addition, such distributions could result in the foreign shareholder being required to file a U.S. tax return and pay tax on the distributions at regular U.S. federal income tax rates. The consequences to a foreign shareholder, including the rate of such withholding and character of such distributions (e.g., as ordinary income or USRPI gain), would vary depending upon the extent of the foreign shareholder’s current and past ownership of the Fund.

The Fund generally does not expect that it will be a QIE. Foreign shareholders should consult their tax advisers and, if holding shares through intermediaries, their intermediaries, concerning the application of these rules to their investment in the Fund. Foreign shareholders also may be subject to “wash sale” rules to prevent the avoidance of the tax-filing and -payment obligations discussed above through the sale and repurchase of Fund shares.

In order for a foreign shareholder to qualify for any exemptions from withholding described above or for lower withholding tax rates under income tax treaties, or to establish an exemption from backup withholding, a foreign shareholder must comply with special certification and filing requirements relating to its non-U.S. status (including, in general, furnishing an IRS Form W-8BEN, W-8BEN-E or substitute form). Foreign shareholders should consult their tax advisors in this regard.

Special rules (including withholding and reporting requirements) apply to foreign partnerships and those holding Fund shares through foreign partnerships. Additional considerations may apply to foreign trusts and estates. Investors holding Fund shares through foreign entities should consult their tax advisers about their particular situation.

A foreign shareholder may be subject to state and local tax and to the U.S. federal estate tax in addition to the U.S. federal income tax referred to above. A beneficial holder of shares who is a non-U.S. person may be subject to state and local tax and to the U.S. federal estate tax in addition to the U.S. federal tax on income referred to above.

The Fund is generally required to withhold and remit to the U.S. Treasury a percentage of taxable distributions and redemption proceeds, if any, paid to any individual shareholder who fails to properly furnish the Fund with a correct taxpayer identification number, who has under-reported dividend or interest income, or who fails to certify to the Fund that he or she is not subject to such withholding. Backup withholding is not an additional tax. Any amounts withheld may be credited against the shareholder’s U.S. federal income tax liability, provided the appropriate information is furnished to the IRS.

Under U.S. Treasury regulations, if a shareholder recognizes a loss of $2 million or more for an individual shareholder or $10 million or more for a corporate shareholder, the shareholder must file with the IRS a disclosure statement on IRS Form 8886. Direct shareholders of portfolio securities are in many cases excepted from this reporting requirement, but under current guidance, shareholders of a regulated investment company are not excepted. Future guidance may extend the current exception from this reporting requirement to shareholders of most or all regulated investment companies. The fact that a loss is reportable under these regulations does not affect the legal determination of whether the taxpayer’s treatment of the loss is proper. Shareholders should consult their tax advisors to determine the applicability of these regulations in light of their individual circumstances.

Sections 1471-1474 of the Code and the U.S. Treasury and IRS guidance issued thereunder (collectively, “FATCA”) generally require the Fund to obtain information sufficient to identify the status of each of its shareholders under FATCA or under an applicable intergovernmental agreement (an “IGA”) between the United States and a foreign government. If a shareholder fails to provide the requested information or otherwise fails to comply with FATCA or an IGA, the Fund may be required to withhold under FATCA at a rate of 30% with respect to that shareholder on ordinary dividends, and, on or after January 1, 2019, 30% of the gross proceeds of sales or

exchanges and certain Capital Gain Dividends it pays. If a payment by the Fund is subject to FATCA withholding, the Fund is required to withhold even if such payment would otherwise be exempt from withholding under the rules applicable to foreign shareholders described above (e.g., Capital Gain Dividends, short-term capital gain dividends and interest-related dividends).

Shareholders that are U.S. persons and own, directly or indirectly, more than 50% of the Fund could be required to report annually their “financial interest” in the Fund’s foreign financial accounts,” if any, on FinCEN Form 114, Report of Foreign Bank and Financial Accounts (FBAR). Shareholders should consult a tax advisor, and persons investing in the Fund through an intermediary should contact their intermediary, regarding the applicability to them of this reporting requirement.

Each prospective investor is urged to consult its tax adviser regarding the applicability of FATCA and any other reporting requirements with respect to the prospective investor’s own situation, including investments through an intermediary.

Special tax rules apply to investments through defined contribution plans and other tax-qualified plans. Shareholders should consult their tax advisers to determine the suitability of shares of the Fund as an investment through such plans and the precise effect of an investment on their particular tax situation.

The Fund may quote certain performance-related information and may compare certain aspects of its portfolio and structure to other substantially similar closed-end funds as categorized by Broadridge Financial Solutions, Inc. (“Broadridge”), Morningstar Inc. or other independent services. Comparison of the Fund to an alternative investment should be made with consideration of differences in features and expected performance. The Fund may obtain data from sources or reporting services, such as Bloomberg Financial and Broadridge, that the Fund believes to be generally accurate.

The Fund, in its advertisements, may refer to pending legislation from time to time and the possible effect of such legislation on investors, investment strategy and related matters. At any time in the future, yields and total return may be higher or lower than past yields and there can be no assurance that any historical results will continue.

Past performance is not indicative of future results. At the time Common Shareholders sell their shares, they may be worth more or less than their original investment.

CUSTODIAN, TRANSFER AGENT, SHAREHOLDER SERVICING AGENT, AUCTION AGENT AND DIVIDEND DISBURSEMENT AGENT

State Street Bank and Trust Company, 801 Pennsylvania Avenue Kansas City, MO 64105, serves as custodian for assets of the Fund. The custodian performs custodial and fund accounting services.

American Stock Transfer & Trust Company, LLC, 6201 15th Avenue, Brooklyn, New York 11219 serves as the transfer agent, registrar and dividend disbursement agent for the Common Shares, as well as agent for the Dividend Reinvestment Plan relating to the Common Shares.

PricewaterhouseCoopers LLP, 1100 Walnut Street, Suite 1300, Kansas City, MO 64106 serves as the independent registered public accounting firm for the Fund. PricewaterhouseCoopers LLP provides audit services, tax assistance and consultation in connection with the review of SEC and IRS filings.

Ropes & Gray LLP, Prudential Tower, 800 Boylston Street, Boston, Massachusetts 02199, passes upon certain legal matters in connection with shares offered by the Fund, and also acts as counsel to the Fund.

A Registration Statement on Form N-2, including any amendments thereto (the “Registration Statement”), relating to the Common Shares of the Fund offered hereby, has been filed by the Fund with the SEC, Washington, D.C. The Prospectus and this Statement of Additional Information are parts of, but do not contain all of the information set forth in, the Registration Statement, including any exhibits and schedules thereto. For further information with respect to the Fund and the Common Shares offered or to be offered hereby, reference is made to the Fund’s Registration Statement. Statements contained in the Prospectus and this Statement of Additional Information as to the contents of any contract or other document referred to are not necessarily complete and in each instance reference is made to the copy of such contract or other document filed as an exhibit to the Registration Statement, each such statement being qualified in all respects by such reference. Copies of the Registration Statement may be inspected without charge at the SEC’s principal office in Washington, D.C., and copies of all or any part thereof may be obtained from the SEC upon the payment of certain fees prescribed by the SEC.

The Fund’s financial statements appearing in the Fund’s annual shareholder report for the year ended July 31, 2017 are incorporated by reference in this Statement of Additional Information and have been so incorporated in reliance upon the reports of PwC, independent registered public accounting firm for the Fund, which report is included in such annual shareholder report. The Fund’s unaudited financial statements appearing in the Fund’s semiannual shareholder report for the fiscal period ended January 31, 2018, are incorporated by reference in this Statement Additional Information. The annual shareholder reports are available upon request and without charge by writing to the Fund at c/o Pacific Investment Management Company LLC, 1633 Broadway, New York, New York 10019.

Procedures for Shareholders to Submit Nominee Candidates for the PIMCO Sponsored Closed-End Funds

A Fund shareholder must follow the following procedures in order to properly submit a nominee recommendation for the Committee’s consideration.

1. The shareholder/stockholder must submit any such recommendation (a “Shareholder Recommendation”) in writing to a Fund, to the attention of the Secretary, at the address of the principal executive offices of the Fund.

2. The Shareholder Recommendation must be delivered to or mailed and received at the principal executive offices of a Fund not less than forty-five (45) calendar days nor more than seventy-five (75) calendar days prior to the date of the Board or shareholder meeting at which the nominee would be elected.

3. The Shareholder Recommendation must include: (i) a statement in writing setting forth (A) the name, age, date of birth, business address, residence address and nationality of the person recommended by the shareholder (the “candidate”); (B) the class and number of all shares of the Fund owned of record or beneficially by the candidate, as reported to such shareholder by the candidate; (C) any other information regarding the candidate called for with respect to director nominees by paragraphs (a), (d), (e) and (f) of Item 401 of Regulation S-K or paragraph (b) of Item 22 of Rule 14a-101 (Schedule 14A) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), adopted by the Securities and Exchange Commission (or the corresponding provisions of any regulation or rule subsequently adopted by the Securities and Exchange Commission or any successor agency applicable to the Fund); (D) any other information regarding the candidate that would be required to be disclosed if the candidate were a nominee in a proxy statement or other filing required to be made in connection with solicitation of proxies for election of Directors/Trustees or directors pursuant to Section 14 of the Exchange Act and the rules and regulations promulgated thereunder; and (E) whether the recommending shareholder believes that the candidate is or will be an “interested person” of the Fund (as defined in the Investment Company Act of 1940, as amended) and, if not an “interested person,” information regarding the candidate that will be sufficient for the Fund to make such determination; (ii) the written and signed consent of the candidate to be named as a nominee and to serve as a Director/Trustee if elected; (iii) the recommending shareholder’s name as it appears on the Fund’s books; (iv) the class and number of all shares of the Fund owned beneficially and of record by the recommending shareholder; and (v) a description of all arrangements or understandings between the recommending shareholder and the candidate and any other person or persons (including their names) pursuant to which the recommendation is being made by the recommending shareholder. In addition, the Committee may require the candidate to furnish such other information as it may reasonably require or deem necessary to determine the eligibility of such candidate to serve on the Board.

Financial highlights for the fiscal period ended January 31, 2018; fiscal years ended July 31, 2017 and 2016; fiscal period ended July 31, 2015; and fiscal years ended November 30, 2014, 2013, 2012, 2011, 2010, 2009 and 2008.

Incorporated into Part B by reference to Registrant’s most recent Certified Shareholder Report on Form N-CSR, filed October 2, 2017 (File No. 811-21238):

Report of Independent Registered Public Accounting Firm dated September 27, 2017

Incorporated into Part B by reference to Registrant’s most recent Certified Shareholder Report on Form N-CSRS, filed April 2, 2018 (File No. 811-21238):

Statement of Changes in Net Assets for the year ended July 31, 2017; the fiscal period from July 31, 2017 to January 31, 2018.

Reference is made to the sales agreement for the Registrant’s common shares filed as exhibit h to the registration statement previously filed on Form N-2 (No. 333-215581) and the section entitled “Plan of Distribution” contained in Registrant’s Prospectus, filed as Part A of Registrant’s Registration Statement incorporated herein by reference.

Reference is made to Article VIII, Sections 1 through 4, of the Registrant’s Amended and Restated Agreement and Declaration of Trust, which is incorporated by reference herein.

Insofar as indemnification for liabilities arising under the Securities Act of 1933, as amended (the “Securities Act”), may be permitted to trustees, officers and controlling persons of the Registrant by the Registrant pursuant to the Trust’s Amended and Restated Agreement and Declaration of Trust, its Amended and Restated Bylaws or otherwise, the Registrant is aware that in the opinion of the Securities and Exchange Commission, such indemnification is against public policy as expressed in the Securities Act and, therefore, is unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by trustees, officers or controlling persons of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such trustees, officers or controlling persons in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

Pacific Investment Management Company LLC (“PIMCO”) is an investment adviser registered under the Advisers Act. The list required by this Item 31 of officers and directors of PIMCO, together with any information as to any business, profession, vocation, or employment of a substantial nature engaged in by such officers and directors during the past two years, is incorporated herein by reference from Form ADV filed by PIMCO pursuant to the Advisers Act (SEC File No. 801-48187).

The account books and other documents required to be maintained by the Registrant pursuant to Section 31(a) of the Investment Company Act of 1940 and the rules thereunder will be maintained at the offices of Pacific Investment Management Company LLC, 1633 Broadway, New York, NY 10019 or the Registrant’s custodian, State Street Bank and Trust Company, 801 Pennsylvania Avenue, Kansas City, Missouri 64105.

The undersigned Registrant undertakes that in a primary offering of securities of the undersigned Registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned Registrant will be a seller to the purchaser and will be considered to offer or sell such securities to the purchaser:

A copy of the Amended and Restated Agreement and Declaration of Trust of PIMCO Corporate & Income Opportunity Fund (the “Fund”), together with all amendments thereto, is on file with the Secretary of State of The Commonwealth of Massachusetts, and notice is hereby given that this instrument is executed on behalf of the Fund by any officer of the Fund as an officer and not individually and that the obligations of or arising out of this instrument are not binding upon any of the Trustees of the Fund or shareholders of the Fund individually, but are binding only upon the assets and property of the Fund.

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant has duly caused this Post-Effective Amendment No. 4 to its Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of New York, and the State of New York on the 8th day of June, 2018.

Pursuant to the requirements of the Securities Act of 1933, this Post-Effective Amendment No. 4 to its Registration Statement has been signed below by the following persons in the capacities and on the date indicated.

		Page
	Prospectus Summary	4
	Summary of Fund Expenses	27
	Financial Highlights	28
	Use of Proceeds	31
	The Fund	31
	Investment Objective and Policies	31
	Portfolio Contents	32
	Use of Leverage	52
	Principal Risks of the Fund	54
	How the Fund Manages Risk	70
	Management of the Fund	73
	Net Asset Value	75
	Distributions	77
	Dividend Reinvestment Plan	78
	Description of Capital Structure	79
	Plan of Distribution	82
	Market and Net Asset Value Information	83
	Anti-Takeover Provisions in the Declaration of Trust	83
	Repurchase of Common Shares; Conversion to Open-End Fund	84
	Tax Matters	85
	Shareholder Servicing Agent, Custodian and Transfer Agent	87
	Independent Registered Public Accounting Firm	87
	Legal Matters	87
	Table of Contents for Statement of Additional Information	88
	Appendix A - Description of Securities Ratings	89

Sales load (as a percentage of offering price)⁽¹⁾	[ - ]%
Offering Expenses Borne by Common Shareholders (as a percentage of offering price)⁽²⁾	[ - ]%
Dividend Reinvestment Plan Fees⁽³⁾	None

	Percentage of Net Assets Attributable to Common Shares (reflecting leverage attributable to ARPS and reverse repurchase agreements)
Management Fees⁽¹⁾	0.78%
Dividend Cost on Preferred Shares⁽²⁾	0.51%
Interest Payments on Borrowed Funds⁽³⁾	0.35%
Other Expenses⁽⁴⁾	0.02%
Total Annual Expenses	1.66%

	1 Year	3 Years	5 Years	10 Years
Total Expenses Incurred	$17	$52	$90	$197

			Investment Operations					Less Distributions to Preferred Shareholders‌^(b)									Less Distributions to Common Shareholders‌^(b)																		Common Share							Ratios/Supplemental Data
																																												Ratios to Average Net Assets
Selected Per Share Data for the Year or Period Ended^:	Net Asset Value Beginning of Year or Period		Net Investment Income‌^(a)		Net Realized/Unrealized Gain (Loss)			From Net Investment Income			From Net Realized Capital Gains			Net Increase (Decrease) in Net Assets Applicable to Common Shareholders Resulting from Operations			From Net Investment Income			From Net Realized Capital Gains			Tax Basis Return of Capital			Total			Increase Resulting from at-the-market offering		Offering Cost Charged to Paid in Capital		Increase Resulting from Tender and Repurchase of Auction-Rate Preferred Shares‌^(c)		Net Asset Value End of Year or Period		Market Price End of Year or Period		Total Investment Return‌^(d)			Net Assets Applicable to Common Shareholders (000s)		Expenses‌^(e)(f)			Expenses Excluding Waivers‌^(e)(f)			Expenses Excluding Interest Expense‌^(e)			Expenses Excluding Interest Expense and Waivers‌^(e)			Net Investment Income (Loss)			Preferred Shares Asset Coverage Per Share		Portfolio Turnover Rate
PIMCO Corporate & Income Opportunity Fund
08/01/2017 - 01/31/2018+	$	14.87	$	0.64	$	0.26		$	(0.04	)	$	0.00		$	0.86		$	(0.78	)	$	0.00		$	0.00		$	(0.78	)	$	0.08	$	0.00	$	0.00	$	15.03	$	16.43		2.00	%	$	1,217,574		1.16	%*		1.16	%*		0.81	%*		0.81	%*		8.45	%*	$	152,884		9	%
7/31/2017		13.27		1.21		2.06			(0.04	)		0.00			3.23			(1.59	)		0.00			(0.14	)		(1.73	)		0.10		0.00		0.00		14.87		16.92		29.18			1,140,768		1.08			1.08			0.83			0.83			8.68			144,819		39
7/31/2016		14.23		1.30		(0.65	)		(0.02	)		0.00			0.63			(1.59	)		0.00			0.00			(1.59	)		N/A		N/A		0.00		13.27		14.75		16.09			946,843		0.89			0.89			0.85			0.85			9.93			124,468		45
12/01/2014 - 07/31/2015^(g)		15.41		0.68		(0.33	)		(0.00	)		0.00			0.35			(1.69	)		0.00			0.00			1.69	‌^(h)		N/A		N/A		0.16		14.23		14.31		(13.61	)		1,006,484		0.91	*		0.91	*		0.90	*		0.90	*		7.01	*		130,743		34
11/30/2014		16.62		1.14		1.06			(0.00	)		(0.01	)		2.19			(1.56	)		(1.84	)		0.00			(3.40	)		N/A		N/A		0.00		15.41		18.50		26.04			1,082,000		0.91			0.91			0.91			0.91			7.36			108,229		44
11/30/2013		17.58		1.43		0.19			(0.00	)		(0.00	)		1.62			(1.82	)		(0.76	)		0.00			(2.58	)		N/A		N/A		0.00		16.62		17.75		(0.15	)		1,149,779		0.91			0.91			0.91			0.91			8.49			113,443		118
11/30/2012		14.22		1.68		3.87			(0.01	)		0.00			5.54			(2.18	)		0.00			0.00			(2.18	)		N/A		N/A		0.00		17.58		20.37		36.86			1,205,090		1.05			1.05			0.93			0.93			10.63			117,697		29
11/30/2011		16.29		1.88		(1.87	)		(0.01	)		0.00			0.00			(2.07	)		0.00			0.00			(2.07	)		N/A		N/A		0.00		14.22		16.78		9.24			967,195		1.09			1.09			0.94			0.94			11.76			99,399		53
11/30/2010		13.63		1.80		2.83			(0.01	)		0.00			4.62			(1.96	)		0.00			0.00			(1.96	)		N/A		N/A		0.00		16.29		17.30		40.36			1,098,920		1.02			1.02			0.93			0.93			11.98			109,530		70
11/30/2009		8.54		1.64		4.85			(0.02	)		0.00			6.47			(1.38	)		0.00			0.00			(1.38	)		N/A		N/A		0.00		13.63		14.00		111.56			911,702		1.32			1.32			1.23			1.23			16.16			95,129		80
11/30/2008		14.34		1.40		(5.52	)		(0.30	)		0.00			(4.42	)		(1.38	)		0.00			0.00			(1.38	)		N/A		N/A		0.00		8.54		7.55		(39.06	)		566,927		1.39	‌⁽ⁱ⁾		1.39	‌⁽ⁱ⁾		1.30	‌⁽ⁱ⁾		1.30	‌⁽ⁱ⁾		11.08			50,082		130

*	Annualized
^	Reflects an amount rounding to less than one cent.
+	Unaudited
(a)	Per share amounts based on average number of common shares outstanding during the year or period.
(b)	The tax characterization of distributions is determined in accordance with federal income tax regulations. See Note 2, Distributions—Common Shares, in the Notes to Financial Statements for more information.
(c)	See Note 14, Auction-Rate Preferred Shares, in the Notes to Financial Statements.
(d)	Total investment return is calculated assuming a purchase of a common share at the market price on the first day and a sale of a common share at the market price on the last day of each year or period reported. Dividends and distributions, if any, are assumed, for purposes of this calculation, to be reinvested at prices obtained under the Funds' dividend reinvestment plan. Total investment return does not reflect brokerage commissions in connection with the purchase or sale of Fund shares.
(e)	Calculated on the basis of income and expenses applicable to both common and preferred shares relative to the average net assets of common shareholders. The expense ratio and net investment income do not reflect the effects of dividend payments to preferred shareholders.
(f)	Interest expense primarily relates to participation in borrowing and financing transactions. See Note 5, Borrowings and Other Financing Transactions, in the Notes to Financial Statements for more information.
(g)	Fiscal year end changed from November 30‌^th to July 31^st.
(h)	Total distributions for the period ended July 31, 2015 may be lower than prior fiscal years due to fiscal year end changes resulting in a reduction of the amount of days in the period ended July 31, 2015.
(i)	Inclusive of expenses offset by custody credits earned on cash balances at the custodian bank

Fiscal Year Ended	Total Amount Outstanding	Asset Coverage per Preferred Share⁽¹⁾	Involuntary Liquidating Preference per ARPS⁽²⁾	Average Market Value per Preferred Share⁽³⁾
July 31, 2017	$237,950,000	$144,819	$25,000	N/A
July 31, 2016	$237,950,000	$124,468	$25,000	N/A
July 31, 2015⁽⁴⁾	$237,950,000	$130,743	$25,000	N/A
November 30, 2014	$325,000,000	$108,229	$25,000	N/A
November 30, 2013	$325,000,000	$113,443	$25,000	N/A
November 30, 2012	$325,000,000	$117,697	$25,000	N/A
November 30, 2011	$325,000,000	$99,399	$25,000	N/A
November 30, 2010	$325,000,000	$109,530	$25,000	N/A
November 30, 2009	$325,000,000	$95,129	$25,000	N/A
November 30, 2008	$565,000,000	$50,082	$25,000	N/A
November 30, 2007	$565,000,000	$66,880	$25,000	N/A

Assumed Return on Portfolio (Net of Expenses)	(10.00)%	(5.00)%	0.00%	5.00%	10.00%
Corresponding Return to Common Shareholders	(15.16)%	(8.06)%	(0.97)%	6.13%	13.22%

Portfolio Manager	Since	Title	Recent Professional Experience
Alfred T. Murata	2014	Portfolio Manager and Managing Director	Mr. Murata is a managing director and portfolio manager in the Newport Beach office, managing income-oriented, multisector credit, opportunistic and securitized strategies. Morningstar named him Fixed- Income Fund Manager of the Year (U.S.) for 2013. Prior to joining PIMCO in 2001, he researched and implemented exotic equity and interest rate derivatives at Nikko Financial Technologies. He has 17 years of investment experience and holds a Ph.D. in engineering-economic systems and operations research from Stanford University. He also earned a J.D. from Stanford Law School and is a member of the State Bar of California.
Mohit Mittal	2014	Portfolio Manager and Managing Director	Mr. Mittal is a managing director and portfolio manager in the Newport Beach office, and a senior member of the liability driven investment and credit portfolio management teams. He manages multi-sector portfolios with added specialization in long credit, investment grade credit, and unconstrained bond portfolios. In addition, he is the head of U.S. investment grade trading desk. Previously, he was a specialist on PIMCO's interest rates and derivatives desk. Mr. Mittal joined the firm in 2007 and holds an MBA in finance from the Wharton School of the University of Pennsylvania and an undergraduate degree in computer science from Indian Institute of Technology (IIT) in Delhi, India.

Title of Class	Amount Authorized	Amount Outstanding
Common Shares	Unlimited	81,003,790
Preferred Shares—ARPS
Class M	4,520	1,884
Class T	4,520	1,770
Class W	4,520	1,847
Class TH	4,520	2,033
Class F	4,520	1,984

Moody's Credit Rating	Applicable Percentage
Aa3 or above	150%
A3 to A1	200%
Baa3 to Baa1	225%
Below Baa3	275%

	Common share market price⁽¹⁾		Common share net asset value		Premium (discount) as a % of net asset value
Quarter	High	Low	High	Low	High	Low
Quarter ended April 30, 2018	$17.51	$15.96	$15.04	$14.67	18.79%	8.14%
Quarter ended January 31, 2018	$17.00	$16.27	$15.11	$14.87	12.74%	9.04%
Quarter ended October 31, 2017	$17.18	$16.23	$15.09	$14.77	15.22%	9.51%
Quarter ended July 31, 2017	$16.92	$15.97	$14.87	$14.40	13.79%	10.44%
Quarter ended April 30, 2017	$16.05	$15.10	$14.45	$13.79	12.64%	8.17%
Quarter ended January 31, 2017	$15.45	$13.39	$13.81	$13.50	11.88%	(0.81)%
Quarter ended October 31, 2016	$15.20	$14.07	$13.71	$13.29	12.51%	4.09%
Quarter ended July 31, 2016	$14.75	$13.70	$13.27	$12.80	11.95%	6.95%
Quarter ended April 30, 2016	$13.91	$12.03	$12.92	$12.30	8.84%	(2.51)%

The Fund	3
Investment Objective and Policies	3
Investment Restrictions	82
Management of the Fund	85
Investment Manager	101
Portfolio Transactions	110
Distributions	113
Description of Shares	114
Anti-Takeover and Other Provisions in the Declaration of Trust	115
Repurchase of Common Shares; Conversion to Open-End Fund	117
Taxation	119
Performance Related and Comparative Information	137
Custodian, Transfer Agent, Shareholder Servicing Agent, Auction Agent and Dividend Disbursement Agent	137
Independent Registered Public Accounting Firm	138
Counsel	138
Registration Statement	138
Financial Statements	138
Appendix A — Procedures for Shareholders to Submit Nominee Candidates	A-1


About this Prospectus Supplement		S-4
Prospectus Supplement Summary		S-5
Use of Proceeds		S-7
Summary of Fund Expenses		S-7
Capitalization		S-7
Market and Net Asset Value Information		S-8
Plan of Distribution		S-9
Legal Matters		S-9
Additional Information		S-9


Prospectus Summary		1
Summary of Fund Expenses		27
Financial Highlights		28
Use of Proceeds		31
The Fund		31
Investment Objective and Policies		31
Portfolio Contents		32
Use of Leverage		52
Principal Risks of the Fund		54
How the Fund Manages Risk		70
Management of the Fund		73
Net Asset Value		75
Distributions		77
Dividend Reinvestment Plan		78
Description of Capital Structure		79
Plan of Distribution		82
Market and Net Asset Value Information		83
Anti-Takeover Provisions in the Declaration of Trust		83
Repurchase of Common Shares; Conversion to Open-End Fund		84
Tax Matters		85
Shareholder Servicing Agent, Custodian and Transfer Agent		87
Independent Registered Public Accounting Firm		87
Legal Matters		87
Table of Contents for Statement of Additional Information		88
Appendix A–Description of Securities Ratings		89


Shareholder Transaction Expenses
Sales load (as a percentage of offering price)			[ ]%
Offering Expenses Borne by Common Shareholders (as a percentage of offering price)			[ ]%
Dividend Reinvestment Plan Fees ⁽¹⁾			None


Annual Expenses
Management Fees⁽²⁾			[ ]%
Dividend Cost on Preferred Shares ⁽³⁾			[ ]%
Interest Payments on Borrowed Funds⁽⁴⁾			[ ]%
Other Expenses⁽⁵⁾			[ ]%
Total Annual Expenses			[ ]%


Name, Address and Year of Birth**	Position(s) Held with the Fund	Term of Office and Length of Time Served	Principal Occupation(s) During the Past 5 Years	Number of Portfolios in Fund Complex Overseen by Trustee***	Other Directorships Held by Trustee During the Past 5 Years

Hans W. Kertess 1939 Class III	Trustee & Chairman of the Board	Since 2003	President, H. Kertess & Co., a financial advisory company; and Senior Adviser (formerly Managing Director), Royal Bank of Canada Capital Markets (since 2004).	93	None


Name, Address and Year of Birth**	Position(s) Held with the Fund	Term of Office and Length of Time Served	Principal Occupation(s) During the Past 5 Years	Number of Portfolios in Fund Complex Overseen by Trustee***	Other Directorships Held by Trustee During the Past 5 Years

Deborah A. DeCotis 1952 Class III	Trustee	Since 2011	Advisory Director, Morgan Stanley & Co., Inc. (since 1996); Member, Circle Financial Group (since 2009); and Member, Council on Foreign Relations (since 2013); Trustee, Smith College (since 2017); and Director, Watford Re (since 2017). Formerly, Co-Chair Special Projects Committee, Memorial Sloan Kettering (2005-2015); Trustee, Stanford University (2010-2015); Principal, LaLoop LLC, a retail accessories company (1999-2014); Director, Helena Rubenstein Foundation (1997-2010); and Director, Armor Holdings (2002-2010).	93	None.
Bradford K. Gallagher 1944 Class II	Trustee	Since 2010	Retired. Founder, Spyglass Investments LLC, a private investment vehicle (since 2001). Formerly, Chairman and Trustee, The Common Fund (2005-2014); Partner, New Technology Ventures Capital Management LLC, a venture capital fund (2011-2013); Chairman and Trustee, Atlantic Maritime Heritage Foundation (2007-2012); and Founder, President and CEO, Cypress Holding Company and Cypress Tree Investment Management Company (1995-2001).	93	Formerly, Chairman and Trustee, Grail Advisors ETF Trust (2009-2010); and Trustee, Nicholas-Applegate Institutional Funds (2007-2010).
James A. Jacobson 1945 Class II	Trustee	Since 2009	Retired. Trustee (since 2002) and Chairman of Investment Committee (since 2007), Ronald McDonald House of New York; and Trustee, New Jersey City University (since 2014). Formerly, Vice Chairman and Managing Director, Spear, Leeds & Kellogg Specialists, LLC, a specialist firm on the New York Stock Exchange (2003-2008).	93	Formerly, Trustee, Alpine Mutual Funds Complex consisting of 18 funds.
William B. Ogden, IV 1945 Class I	Trustee	Since 2006	Retired. Formerly, Asset Management Industry Consultant; and Managing Director, Investment Banking Division of Citigroup Global Markets Inc.	93	None


Name, Address and Year of Birth**	Position(s) Held with the Fund	Term of Office and Length of Time Served	Principal Occupation(s) During the Past 5 Years	Number of Portfolios in Fund Complex Overseen by Trustee***	Other Directorships Held by Trustee During the Past 5 Years

Alan Rappaport 1953 Class I	Trustee	Since 2010	Advisory Director (formerly Vice Chairman), Roundtable Investment Partners (since 2009); Adjunct Professor, New York University Stern School of Business (since 2011); Lecturer, Stanford University Graduate School of Business (since 2013); and Director, Victory Capital Holdings, Inc., an asset management firm (since 2013). Formerly, Member of Board of Overseers, NYU Langone Medical Center (2015-2016); Trustee, American Museum of Natural History (2005-2015); Trustee, NYU Langone Medical Center (2007-2015); Vice Chairman (formerly Chairman and President), U.S. Trust (formerly Private Bank of Bank of America, the predecessor entity of U.S. Trust) (2001-2008).	93	None.
Interested Trustees
Name, Address and Year of Birth**	Position(s) Held with the Fund	Term of Office and Length of Time Served	Principal Occupation(s) During the Past 5 Years	Number of Portfolios in Fund Complex Overseen by Trustee***	Other Directorships Held by Trustee

Craig A. Dawson**** 1968 650 Newport Center Drive, Newport Beach, CA 92660 Class III	Trustee	Since 2014	Managing Director and Head of PIMCO Europe, Middle East and Africa (since 2016). Director of a number of PIMCO’s European investment vehicles and affiliates (since 2008). Formerly, Head of Strategic Business Management, PIMCO (2014-2016), head of PIMCO’s Munich office and head of European product management for PIMCO.	26	None


Name, Address and Year of Birth	Position(s) Held with Fund	Term of Office and Length of Time Served	Principal Occupation(s) During the Past 5 Years
Peter G. Strelow^** 1970	President	Since 2014	Managing Director and Co-Chief Operating Officer, PIMCO. President, PIMCO-Managed Funds, PIMCO Funds, PIMCO Variable Insurance Trust, PIMCO ETF Trust, PIMCO Equity Series and PIMCO Equity Series VIT. Formerly, Chief Administrative Officer, PIMCO.
Keisha Audain-Pressley^** 1975	Chief Compliance Officer	Since January2018	Senior Vice President and Deputy Chief Compliance Officer, PIMCO. Chief Compliance Officer, PIMCO-Managed Funds.

Joshua D. Ratner^*** 1976	Vice President, Secretary and Chief Legal Officer	Since 2014	Executive Vice President and Deputy General Counsel, PIMCO. Chief Legal Officer, PIMCO Investments LLC. Vice President, Secretary and Chief Legal Officer, PIMCO-Managed Funds. Vice President—Senior Counsel, Secretary, PIMCO Funds, PIMCO Variable Insurance Trust, PIMCO ETF Trust, PIMCO Equity Series and PIMCO Equity Series VIT.

Trent W. Walker^** 1974	Treasurer	Since 2017	Executive Vice President, PIMCO. Assistant Treasurer, PIMCO-Managed Funds. Treasurer, PIMCO Funds, PIMCO Variable Insurance Trust, PIMCO ETF Trust, PIMCO Equity Series and PIMCO Equity Series VIT.
Ryan Leshaw^** 1980	Assistant Secretary	Since 2014	Senior Vice President and Senior Counsel, PIMCO. Assistant Secretary, PIMCO-Managed Funds, PIMCO Funds, PIMCO Variable Insurance Trust, PIMCO ETF Trust, PIMCO Equity Series and PIMCO Equity Series VIT. Formerly, Associate, Willkie Farr & Gallagher LLP.

Wu-Kwan Kit^** 1981	Assistant Secretary	Since 2017	Vice President and Counsel, PIMCO. Assistant Secretary, PIMCO-Managed Funds, PIMCO Funds, PIMCO Variable Insurance Trust, PIMCO ETF Trust, PIMCO Equity Series and PIMCO Equity Series VIT. Formerly, Assistant General Counsel, VanEck Associates Corp.
Stacie D. Anctil^** 1969	Vice President	Since 2015	Senior Vice President, PIMCO. Vice President, PIMCO-Managed Funds, PIMCO Funds, PIMCO Variable Insurance Trust, PIMCO ETF Trust, PIMCO Equity Series and PIMCO Equity Series VIT.


Name of Trustee	Dollar Range of Equity Securities in the Fund	Aggregate Dollar Range of Equity Securities in All Registered Investment Companies Overseen by Trustee in Family of Investment Companies*
Independent Trustees
Bradford K. Gallagher	None	Over $100,000

James A. Jacobson	None	Over $100,000

Hans W. Kertess	None	Over $100,000

William B. Ogden, IV	None	Over $100,000

Alan Rappaport Over	None	Over $100,000

Deborah A. DeCotis	None	Over $100,000
Interested Trustees
John C. Maney	$1-10,000	Over $100,000

Craig A. Dawson	None	Over $100,000


Name of Trustee	Name of Owners and Relations to Trustee	Company	Title of Class	Value of Securities	Percent of Class

Deborah A. DeCotis	None	N/A	N/A	N/A	N/A

Bradford K. Gallagher	None	N/A	N/A	N/A	N/A

James A. Jacobson	None	N/A	N/A	N/A	N/A



Hans W. Kertess	None	N/A	N/A	N/A	N/A

William B. Ogden, IV*	None	N/A	N/A	N/A	N/A

Alan Rappaport	None	N/A	N/A	N/A	N/A


Beneficial Owner	Class	Percentage of Class
Bank of New York Mellon One Wall Street New York, New York 10286	Preferred Shares	53.26%

UBS AG Bahnhofstrasse 45, PO Box CH-8021 Zurich, Switzerland	Preferred Shares	34.06%


Record Owner	Class	Percentage of Class

American Enterprise Investment Services Inc. 2723 Ameriprise Financial Center Minneapolis, MN 55474	Common Shares	5.13%

Charles Schwab & Co Inc. 101 Montgomery St San Francisco, CA 94104-4151	Common Shares	17.77%

Merrill Lynch Professional Clearing Corp. 222 Broadway New York, NY 10038	Common Shares	6.78%

Morgan Stanley Smith Barney Harborside Financial Center, Plaza 2 Jersey City, NJ 07311	Common Shares	5.53%



National Financial Services LLC 200 Liberty St., One World Financial Center New York, NY 10281-1003	Common Shares	19.29%

Pershing LLC 1 Pershing Plz Jersey City, NJ 07399-000	Common Shares	6.84%

TD Ameritrade Inc. PO Box 2226 Omaha, NE 68103-2226	Common Shares	10.12%


Name of Trustee	Aggregate compensation from the Fund for the Fiscal Year Ended July 31, 2017**	Pension or Retirement Benefits Accrued as Part of Fund Expenses	Estimated Annual Benefits Upon Retirement	Total Compensation from the Fund Complex Paid to the Trustees for the Calendar Year Ending December 31, 2017*
Deborah A. DeCotis	$19,515	N/A	N/A	$470,000
Bradford K. Gallagher	$19,515	N/A	N/A	$460,000
James A. Jacobson	$23,853	N/A	N/A	$535,000
Hans W. Kertess	$26,021	N/A	N/A	$535,000
William B. Ogden, IV	$19,515	N/A	N/A	$465,000
Alan Rappaport	$19,515	N/A	N/A	$470,000


Portfolio Manager	Total Number of Accounts	Total Assets of All Accounts (in $ Millions)	Number of Accounts Paying a Performance Fee	Total Assets of Accounts Paying a Performance Fee (in $ Millions)
*Alfred T. Murata*
Registered Investment Companies	18	$108,704.29	0	$0.00
Other Pooled Investment Vehicles	8	$16,904.35	0	$0.00
Other Accounts	11	$1,566.61	0	$0.00
*Mohit Mittal*
Registered Investment Companies	11	$21,608.97	0	$0.00
Other Pooled Investment Vehicles	13	$7,621.73	2	$1,717.95
Other Accounts	135	$56,337.97	3	$682.95


Name of Portfolio Manager		Dollar Range of Equity Securities in the Fund
Alfred T. Murata		None
Mohit Mittal		None


Broker or Dealer		Value of Securities Held by the Fund as of July 31, 2017
CITIGROUP, INC.		$51,657,000
J.P. MORGAN SECURITIES		$20,375,000
BNP PARIBAS		$6,441,000
CREDIT SUISSE		$5,678,000
MERRILL LYNCH & CO., INC.		$5,482,000
DEUTSCHE BANK		$3,795,000


Title of Class				Number of Record Holders
Common Shares, par value $0.00001				109
Preferred Shares				57


PIMCO CORPORATE & INCOME OPPORTUNITY FUND

By:		Peter G. Strelow*
Name:		Peter G. Strelow
Title:		President


Name	Capacity	Date

Peter G. Strelow*	President (Principal Executive Officer)	June 8, 2018
Peter G. Strelow	President (Principal Executive Officer)

Trent W. Walker*	Treasurer (Principal Financial & Accounting Officer)	June 8, 2018
Trent W. Walker

Craig A. Dawson*	Trustee	June 8, 2018
Craig A. Dawson	Trustee

Deborah A. DeCotis*	Trustee	June 8, 2018
Deborah A. DeCotis	Trustee

Bradford K. Gallagher*	Trustee	June 8, 2018
Bradford K. Gallagher	Trustee

James A. Jacobson*	Trustee	June 8, 2018
James A. Jacobson	Trustee

Hans W. Kertess*	Trustee	June 8, 2018
Hans W. Kertess	Trustee

John C. Maney*	Trustee	June 8, 2018
John C. Maney	Trustee


Exhibit		Exhibit Name

n.		Consent of PricewaterhouseCoopers LLP, the Registrant’s independent registered public accounting firm