Table of Contents

As filed with the Securities and Exchange Commission on March 17, 2023

Securities Act File No. 333-[          ]

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-14

REGISTRATION STATEMENT

UNDER

WESTERN ASSET MANAGED MUNICIPALS FUND INC.

(Exact Name of Registrant as Specified in Charter)

620 Eighth Avenue, 47th Floor

New York, New York 10018

(Address of Principal Executive Offices: Number, Street, City, State, Zip Code)

1-888-777-0102

(Area Code and Telephone Number)

Jane Trust

Franklin Templeton

620 Eighth Avenue, 47th Floor

New York, New York 10018

(Name and Address of Agent for Services)

with copies to:

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 which specifically states that this registration statement shall thereafter become effective in accordance with section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the Commission acting pursuant to said section 8(a), may determine.

Table of Contents

WESTERN ASSET MANAGED MUNICIPALS FUND INC.

WESTERN ASSET MUNICIPAL PARTNERS FUND INC.

WESTERN ASSET INTERMEDIATE MUNI FUND INC.

620 Eighth Avenue, 47th Floor

New York, New York 10018

, 2023

Dear Stockholder:

A Joint Special Meeting of Stockholders (the “Meeting”) of Western Asset Managed Municipals Fund Inc. (“MMU”), Western Asset Municipal Partners Fund Inc. (“MNP”) and Western Asset Intermediate Muni Fund Inc. (“SBI” and together with MMU and MNP, the “Funds”) will be held at 280 Park Avenue, New York, New York 10017, on [ ], 2023 at [10:00 a.m.], Eastern Time, for the purposes of considering and voting on the proposals (each a “Proposal” and collectively, the “Proposals”) to approve the mergers of each of MNP and SBI (each a “Target Fund” and collectively, the “Target Funds”) with and into MMU in accordance with the Maryland General Corporation Law (each a “Merger” and collectively, the “Mergers”).

The attached Proxy Statement/Prospectus asks for your approval of the Proposals applicable to your Fund. After careful consideration, the Board of each Fund recommends that you vote “FOR” each Proposal.

As a result of each Merger, each share of common stock of each Target Fund would convert into an equivalent dollar amount (to the nearest $0.001) of full shares of common stock of MMU, based on the net asset value of the Target Fund’s shares of common stock outstanding as of the close of trading on the New York Stock Exchange (“NYSE”) on the business day immediately prior to the closing time of each respective Merger. MMU will not issue fractional shares to Target Fund stockholders. In lieu of issuing fractional shares, MMU will pay cash to each former holder of Target Fund common stock in an amount equal to the value of the fractional shares of MMU common stock that the investor would otherwise have received in the applicable Merger. The currently issued and outstanding common stock of MMU will remain issued and outstanding.

In addition, each of the Target Funds have a series of preferred stock outstanding: Variable Rate Demand Preferred Stock (“VRDPS”). MNP and MMU also each have Auction Rate Cumulative Preferred Stock (“ARPS”) outstanding.

Subject to approval of the respective Proposal by the stockholders of MNP, MNP’s ARPS will be redeemed in connection with—and prior to the closing of—its Merger, pursuant to the redemption terms outlined in the Articles Supplementary for the ARPS. Subject to the approval of either Proposal, MMU’s ARPS will be redeemed in connection with—and prior to the closing of—a Merger, pursuant to the redemption terms outlined in the Articles Supplementary for the ARPS. MNP and MMU each would provide notice of such a redemption to its ARPS holders following the approval of the respective Proposal at the Meeting and on a timeline consistent with the notice requirements in the Articles Supplementary for each series of ARPS and the Investment Company Act of 1940, as amended.

With respect to the VRDPS, MMU will issue and deliver to each Target Fund newly issued shares of MMU’s VRDPS with the same aggregate liquidation preference and terms as SBI’s Series 1 VRDPS and MNP’s Series 1 VRDPS, respectively, issued and outstanding immediately before the date of the Merger. As the liquidation preference for the newly issued shares of MMU’s VRDPS that will replace the MNP’s Series 1 VRDPS will be equal to the liquidation preference of the existing MMU’s Series 1 VRDPS, MMU will issue a corresponding number of newly issued shares of MMU’s VRDPS so that the aggregate liquidation preference for the replaced MNP’s Series 1 VRDPS remains the same. In addition, MMU will also issue and deliver to each Target Fund newly issued shares of MMU’s VRDPS with the same aggregate liquidation preference as SBI’s ARPS and MNP’s ARPS, respectively, issued and outstanding as of December 31, 2022. Finally, MMU will issue additional VRDPS to replace its ARPS that are issued and outstanding as of December 31, 2022. The newly issued shares of

Table of Contents

MMU’s VRDPS would have equal liquidation preference per share as any other outstanding MMU’s VRDPS and equal priority with any other outstanding MMU’s VRDPS as to the payment of dividends and as to the distribution of assets upon dissolution, liquidation or winding up of the affairs of MMU. The accrual for SBI’s Series 1 VRDPS and MNP’s Series 1 VRDPS with respect to any accrued and unpaid dividends as of date of the Mergers would be assumed by MMU and would apply and be payable on an equivalent share-for-share basis and on the same dividend payment schedule to avoid any disruption to VRDPS holders. In connection with the Mergers but separate from the issuance of new shares of MMU’s VRDPS to each Target Fund’s current VRDPS holders and as a replacement for each Target Fund’s redeemed ARPS, MMU will issue additional shares of VRDPS to enable MMU to seek to approximately maintain its current level of leverage.

Both Target Funds are closed-end, diversified management investment companies listed on the NYSE.

The Board of each Fund believes that the Mergers are in the best interests of the stockholders of each Fund. The Funds have substantially similar investment objectives, policies and strategies. The Mergers will result in more streamlined product offerings, allowing for more focused marketing and stockholder servicing efforts. Moreover, the combined Fund will likely benefit from economies of scale, as one set of fixed expenses would be spread over a larger asset base, as well as from enhanced market liquidity and may experience improved market price trading relative to net asset value (“NAV”).

Your vote is very important to us regardless of the number of shares you own. Whether or not you plan to attend the Meeting in person, please read the Proxy Statement/Prospectus and cast your vote promptly. To vote, simply date, sign and return the proxy card in the enclosed postage-paid envelope or follow the instructions on the proxy card for voting by touch-tone telephone or on the Internet.

If you have any questions about the Proposals to be voted on, please call Georgeson LLC, the proxy solicitor, at (888) 867-6963

It is important that your vote be received no later than the time of the Meeting.

Sincerely,

Jane Trust

President and Chief Executive Officer

Western Asset Managed Municipals Fund Inc.

Western Asset Municipal Partners Fund Inc.

Western Asset Intermediate Muni Fund Inc.

2

Table of Contents

WESTERN ASSET MANAGED MUNICIPALS FUND INC.

WESTERN ASSET MUNICIPAL PARTNERS FUND INC.

WESTERN ASSET INTERMEDIATE MUNI FUND INC.

IMPORTANT NEWS FOR STOCKHOLDERS

The enclosed combined Proxy Statement/Prospectus describes separate proposals (each a “Proposal” and together, the “Proposals”) to merge each of Western Asset Municipal Partners Fund Inc. (“MNP”) and Western Asset Intermediate Muni Fund Inc. (“SBI”) with and into Western Asset Managed Municipals Fund Inc. (“MMU” and together with MNP and SBI, the “Funds”) in accordance with the Maryland General Corporation Law (each a “Merger” and collectively, the “Mergers”).

While we encourage you to read the full text of the enclosed combined Proxy Statement/Prospectus, below is a brief overview of the Proposals. Please refer to the more complete information contained elsewhere in the combined Proxy Statement/Prospectus about the Proposals.

COMMON QUESTIONS ABOUT THE PROPOSED MERGER

Q. Why am I receiving the Proxy Statement/Prospectus?

A. As a stockholder of either MNP or SBI (each a “Target Fund” and collectively, the “Target Funds”), you are being asked to vote in favor of a proposal to merge your Target Fund with and into MMU in accordance with the Maryland General Corporation Law.

As a stockholder of MMU, you are being asked to vote in favor of both proposed Mergers of the Target Funds with and into MMU in accordance with the Maryland General Corporation Law.

Q. How will the Mergers affect me?

A. If each Merger is approved, the applicable Target Fund will be merged with and into MMU in accordance with the Maryland General Corporation Law. Each Target Fund’s assets and liabilities will be combined with the assets and liabilities of MMU, and stockholders of the Target Funds will become stockholders of MMU.

Q. What will happen to the common stock of MNP, SBI and/or MMU that I currently own as a result of the Merger?

A. As a result of each Merger, each share of common stock of the applicable Target Fund would convert into an equivalent dollar amount (to the nearest $0.001) of full shares of common stock of MMU, based on the net asset value of each Fund’s shares of common stock outstanding as of the close of trading on the New York Stock Exchange (“NYSE”) on the business day immediately prior to the closing time of each respective Merger. MMU will not issue fractional shares to each holder of Target Fund common shares. In lieu of issuing fractional shares, MMU will pay cash to each former Target Fund stockholder in an amount equal to the value of the fractional shares of MMU common stock that the investor would otherwise have received in the applicable Merger. The currently issued and outstanding shares of MMU common stock will remain issued and outstanding. Stockholders of MMU will be stockholders in a larger fund.

Table of Contents

Upon the consummation of each Merger, all shares of a Target Fund’s common stock shall cease to be outstanding, shall automatically be cancelled and shall cease to exist and the holders of certificates or book entry shares which, immediately prior to the effective date of the applicable Merger, represented such shares of the Target Fund common stock shall cease to have any rights with respect thereto, except the right to receive the consideration described above. Neither Merger is contingent upon the approval of the other Merger.

Q. What will happen to the preferred stock of MNP, SBI and/or MMU that I currently own as a result of the Merger?

A. For holders of Variable Rate Demand Preferred Stock (“VRDPS”):

As a result of each Merger, MMU will issue and deliver to each Target Fund newly issued shares of MMU’s VRDPS with the same aggregate liquidation preference and terms as SBI’s Series 1 VRDPS and MNP’s Series 1 VRDPS, respectively, issued and outstanding immediately before the date of the Merger. As the liquidation preference for the newly issued shares of MMU’s VRDPS that will replace the MNP’s Series 1 VRDPS will be equal to the liquidation preference of the existing MMU’s Series 1 VRDPS, MMU will issue a corresponding number of newly issued shares of MMU’s VRDPS so that the aggregate liquidation preference for the replaced MNP’s Series 1 VRDPS remains the same. In addition, MMU will also issue and deliver to each Target Fund newly issued shares of MMU’s VRDPS with the same aggregate liquidation preference as SBI’s ARPS and MNP’s ARPS, respectively, issued and outstanding as of December 31, 2022. Finally, MMU will issue additional VRDPS to replace its ARPS that are issued and outstanding as of December 31, 2022. The newly issued shares of MMU’s VRDPS would have equal liquidation preference per share as any other outstanding MMU’s VRDPS and equal priority with any other outstanding MMU’s VRDPS as to the payment of dividends and as to the distribution of assets upon dissolution, liquidation or winding up of the affairs of MMU. The accrual for SBI’s Series 1 VRDPS and MNP’s Series 1 VRDPS with respect to any accrued and unpaid dividends as of date of the Mergers would be assumed by MMU and would apply and be payable on an equivalent share-for-share basis and on the same dividend payment schedule to avoid any disruption to VRDPS holders. In connection with the Mergers but separate from the issuance of new shares of MMU’s VRDPS to each Target Fund’s current VRDPS holders and as a replacement for each Target Fund’s redeemed ARPS, MMU will issue additional shares of VRDPS to enable MMU to seek to approximately maintain its current level of leverage.

Upon the consummation of each Merger, all of a Target Fund’s VRDPS shall cease to be outstanding, shall automatically be cancelled and shall cease to exist and the holders of certificates or book entry shares which, immediately prior to the effective date of the applicable Merger, represented such VRDPS of the Target Fund shall cease to have any rights with respect thereto, except the right to receive the consideration described above. Neither Merger is contingent upon the approval of the other Merger.

A. For holders of Auction Rate Cumulative Preferred Stock (“ARPS”):

Subject to approval of the respective Proposal by the stockholders of MNP, MNP’s ARPS will be redeemed in connection with—and prior to the closing of—its Merger, pursuant to the redemption terms outlined in the Articles Supplementary for the ARPS. Subject to the approval of either Proposal, MMU’s ARPS will be redeemed in connection with—and prior to the closing of—a Merger, pursuant to the redemption terms outlined in the Articles Supplementary for the ARPS. MNP and MMU each would provide notice of such a redemption to its ARPS holders following the approval of the Proposal at the Meeting and on a timeline consistent with the notice requirements in the Articles Supplementary for each series of ARPS and the Investment Company Act of 1940, as amended (the “1940 Act”).

Q. What will the combined Fund be known as?

A. If both Mergers are effected, MMU, the surviving fund, will retain the name “Western Asset Managed Municipals Fund Inc.” and will keep its NYSE ticker symbol “MMU”.

2

Table of Contents

Q. What are the benefits of the Mergers?

A. The Board of Directors of each Fund believes that the Mergers are in the best interests of the stockholders of each Fund. The Funds have similar investment objectives, policies and strategies. In addition, after careful consideration, the Board of Directors of each Target Fund believes that the Mergers will benefit the stockholders of each Target Fund for the following reasons:

It is anticipated that the combined Fund will likely benefit from economies of scale, as one set of fixed expenses would be spread over a larger asset base, as well as from enhanced market liquidity and may experience improved market price trading relative to net asset value (“NAV”).

It is anticipated that the combined Fund would have a lower expense level with estimated aggregate cost savings of approximately $768,666 annually, with $521,815 expected to be attributed to reduced operating costs and $246,851 expected from reduced interest expenses.

The total expense ratio experienced by MNP and MMU stockholders is expected to decrease as a result of the Mergers. The total expense ratio experienced by SBI stockholders is expected to increase as a result of its Merger, but the increase would be as a result of the greater leverage usage of MMU, which is expected to result in higher distributions to SBI stockholders but also increases the cost of leverage borne by the Fund and results in higher management fees (which are charged on gross assets).

MNP currently pays an investment management fee to LMPFA, calculated daily and paid monthly, at an annual rate of 0.55% of its average weekly net assets. Both SBI and MMU currently pay an investment management fee to LMPFA, calculated daily and paid monthly, at an annual rate of 0.55% of its average daily net assets.

The following table shows the estimated expenses of each Fund and on a pro forma basis as of December 31, 2022. The net management fees in the below table differ due to differences in the percentage of leverage outstanding for each Fund.

The larger asset base of the combined Fund relative to each Fund may provide greater financial flexibility. In particular, as the merged larger entity, MMU stockholders may benefit from access to more attractive leverage terms (i.e. lower borrowing costs on debt and preferred stock) and a wider range of alternatives for raising capital to growing capital.

A larger fund size and additional trading has the potential to make the merged fund more attractive to traditional and institutional investors. There is also the potential for tighter bid/ask spreads in the secondary market and guiding the combined Fund’s market price to trade closer to its NAV.

In addition to diversification from a larger pool of assets, a more streamlined product will allow for more focused marketing and stockholder servicing efforts.

3

Table of Contents

At a meeting held on February 8 and 9, 2023, the Board of Directors of each Fund, including all of the Directors who are not “interested persons” of the Funds under the 1940 Act (the “Independent Directors”), unanimously approved an Agreement and Plan of Merger with respect to each Fund.

Q. Who do we expect to vote on the Mergers?

A: Each Fund’s common and preferred stockholders are being asked to vote, together as a class, on the Merger.

Q. Are MMU’s investment objectives and policies similar to those of the Target Funds?

A. MMU’s investment objectives, policies and strategies are substantially similar to those of the Target Funds.

Comparison of MNP and MMU Investment Objectives and Strategies

4

Table of Contents

Comparison of SBI and MMU Investment Objectives and Strategies

5

Table of Contents

6

Table of Contents

Please see “Comparison of Investment Objectives, Principal Investment Strategies, and Principal Risks” in the Proxy Statement/Prospectus for a more complete comparison of the Funds’ investment objectives, policies and a summary of the principal risks of investing in the Funds.

Q. How does each Target Fund’s performance compare to MMU’s?

A. For each Target Fund and MMU, set forth below are the average annual total returns for the Fund’s common stock, on the basis of NAV price, for various periods ended December 31, 2022, as well as comparative performance information for each Fund’s performance benchmark, Lipper peer group category average and ranking.

Q. How will the Mergers affect fees and expenses?

A. For MNP, assuming the Merger had occurred on December 31, 2022, the combined Fund would have (i) a total annual fund operating expense ratio for its shares of common stock that is lower than that of the corresponding shares of common stock of the MNP prior to the Merger, and (ii) a net annual fund operating expense ratio (i.e., the annual fund operating expense ratio after waivers and reimbursements under a contractual expense limitation agreement) for its shares of common stock that is lower than that of the corresponding shares of common stock of MNP prior to the Merger.

7

Table of Contents

For SBI, assuming the Merger had occurred on December 31, 2022, the combined Fund would have (i) a total annual fund operating expense ratio for its shares of common stock that is higher than that of the corresponding shares of common stock of the SBI prior to the Merger, and (ii) a net annual fund operating expense ratio (i.e., the annual fund operating expense ratio after waivers and reimbursements under a contractual expense limitation agreement) for its shares of common stock that is higher than that of the corresponding shares of common stock of SBI prior to the Merger.

For MMU, assuming the Mergers have occurred on December 31, 2022, the combined Fund would have (i) a total annual fund operating expense ratio for its shares of common stock that is lower than that of the corresponding shares of common stock of the MMU prior to the Merger, and (ii) a net annual fund operating expense ratio (i.e., the annual fund operating expense ratio after waivers and reimbursements under a contractual expense limitation agreement) for its shares of common stock that is lower than that of the corresponding shares of common stock of MMU prior to the Mergers.

MNP currently pays an investment management fee to LMPFA, calculated daily and paid monthly, at an annual rate of 0.55% of its average weekly net assets. Both SBI and MMU currently pay an investment management fee to LMPFA, calculated daily and paid monthly, at an annual rate of 0.55% of its average daily net assets.

Q: Will management institute a fee waiver if a Merger is approved?

If either Merger is approved, MMU will institute a five basis point (0.05%) fee waiver of the investment management fee for a one-year period following the Mergers, or for as long as necessary to ensure the Funds only bear half of the Merger-related expenses.

Q. What impact will the Mergers have on leverage levels?

A. As of December 31, 2022, the leverage ratio of MMU is 32.7% while the leverage ratios of MNP and SBI are 36.5% and 27.2%, respectively. The leverage ratio of the combined Fund is expected to be that of MMU’s, with possible incremental increases. The cost of leverage of the combined Fund will result in a reduced expense ratio for MNP and MMU. The cost of leverage for SBI will increase its gross expense ratio, but the increase in leverage is expected to result in higher distributions for SBI stockholders.

The table below illustrates the leverage of each Fund on a standalone basis.

Following the Mergers, the combined Fund may determine to increase leverage by issuing additional VRDPS, subject to market conditions.

8

Table of Contents

Q. How will the Mergers impact distributions?

A. If the Mergers are approved, it is anticipated that stockholders of each Target Fund will see higher distributions primarily due to an increased use of leverage. Distributions are expected to be in line with historic distributions received by MMU stockholders.

Q. What are the Funds’ capital loss carryovers?

A. As of December 31, 2022, the Funds are entitled to capital loss carryovers for federal income tax purposes in the amounts set forth below: Capital loss carryovers are favorable tax assets that can be used by a fund to offset income and gains in future taxable periods.

Q. Will I have to pay any taxes as a result of the Mergers?

A. Each Merger is intended to qualify as a tax-free reorganization within the meaning of Section 368(a) of the Internal Revenue Code of 1986, as amended (the “Code”). Assuming that each Merger qualifies for such treatment, you generally will not recognize a gain or loss for federal income tax purposes as a result of the Merger. Target Fund stockholders may, however, recognize gain or loss with respect to any cash those stockholders receive pursuant to a Merger in lieu of fractional shares. As a condition to the closing of the Mergers, each Fund will receive an opinion of counsel to the effect that each Merger will qualify for such treatment. Opinions of counsel are not binding on the Internal Revenue Service or the courts. You should talk to your tax advisor about any state, local and other tax consequences of the Mergers. See “Proposals 1.A and 1.B—Information About the Proposed Mergers—Federal Income Tax Consequences.”

Q. Who will pay for the Mergers?

A. The costs of the Mergers, including the costs of preparing, printing, assembling and mailing material in connection with this solicitation of proxies are estimated to be approximately $322,189 for MNP, $329,541 for SBI and $446,297 for MMU. The Funds will bear the costs of each Merger. However, if either Merger is approved, LMPFA will institute a five basis point (0.05%) fee waiver of the combined Fund’s management fee for one-year post merger, or as long as necessary to ensure that the combined Fund only bears half of the Merger-related expenses. The Merger-related expenses should also be offset by the per year operating cost savings. In the event that either SBI or MNP does not merge with and into MMU, or the Mergers are not consummated at all, each of MNP, SBI and MMU would bear its related expenses of the Mergers.

Q. How does the Board of Directors of each Fund recommend that I vote on the Mergers?

A. After careful consideration, MNP’s Board of Directors, including all of its Independent Directors, unanimously recommend that you vote FOR its Merger.

After careful consideration, SBI’s Board of Directors, including all of its Independent Directors, unanimously recommend that you vote FOR its Merger.

After careful consideration, MMU’s Board of Directors, including all of the Independent Directors, unanimously recommend that you vote FOR the Mergers.

9

Table of Contents

Q. What will happen if a Merger is not approved?

A. Neither Merger is contingent upon the approval of the other Merger. If only one Merger is approved, that Merger will be consummated. If one or both Mergers is not approved, MNP, SBI and MMU (as applicable) will continue as separate investment companies, and each Board will consider such alternatives as it determines to be in the best interests of Fund stockholders, including re-proposing one or both Mergers, as applicable.

Q. When are the Mergers expected to happen?

A. If each Fund’s stockholders approve the Mergers at the Meeting on [●], 2023 (without the need to adjourn to solicit additional votes) and all other conditions to closing are satisfied (or waived), the Mergers are expected to take effect on or about [●], 2023, or such other date as the parties may agree.

Q. Will my vote make a difference?

A. Your vote is very important and makes a difference in the governance of each Fund, no matter how many shares you own. Your vote can help ensure that the Proposals recommended by the Board of Directors of each Fund can be implemented. We encourage all stockholders to participate in the governance of the Funds.

Q. Whom do I call if I have questions?

A. If you need more information, or have any questions about voting, please call Georgeson LLC, the proxy solicitor, at (888) 867-6963.

Q. How do I vote my shares?

A. You can provide voting instructions by telephone by calling the toll-free number on the enclosed proxy card or electronically by going to the Internet address provided on the proxy card and following the instructions, using your proxy card as a guide. Alternatively, you can vote your shares by signing and dating the enclosed proxy card and mailing it in the enclosed postage-paid envelope.

A stockholder may revoke a proxy at any time on or before the Meeting by (1) submitting to the applicable Fund a subsequently dated proxy, (2) delivering to the applicable Fund a written notice of revocation (addressed to the Secretary at the principal executive office of the Funds at the address shown at the beginning of this Proxy Statement/Prospectus) or (3) otherwise giving notice of revocation at the Meeting, at all times prior to the exercise of the authority granted in the proxy card. Merely attending the Meeting, however, will not revoke any previously executed proxy. Unless revoked, all valid and executed proxies will be voted in accordance with the specifications thereon or, in the absence of such specifications, for approval of the Proposals.

You may also attend the Meeting and vote in person. However, even if you intend to attend the Meeting, we encourage you to provide voting instructions by one of the methods described above.

It is important that you vote promptly.

10

Table of Contents

WESTERN ASSET MANAGED MUNICIPALS FUND INC.

WESTERN ASSET MUNICIPAL PARTNERS FUND INC.

WESTERN ASSET INTERMEDIATE MUNI FUND INC.

620 Eighth Avenue, 47th Floor

New York, New York 10018

NOTICE OF A JOINT SPECIAL MEETING OF STOCKHOLDERS

To the Stockholders:

A Joint Special Meeting of Stockholders (the “Meeting”) of Western Asset Managed Municipals Fund Inc. (“MMU”), Western Asset Municipal Partners Fund Inc. (“MNP”) and Western Asset Intermediate Muni Fund Inc. (“SBI” and together with MMU and MNP, the “Funds”) will be held at 280 Park Avenue, New York, New York, on Friday, [●], 2023 at [10:00 a.m.], Eastern Time, for the purposes of considering and voting on the following proposals (each a “Proposal,” and collectively, the “Proposals”):

The Board of each Fund recommends that you vote “FOR” the Proposals upon which you are being asked to vote.

Stockholders of record at the close of business on [    ], 2023 are entitled to vote at the Meeting and at any adjournments or postponements thereof.

By order of the Board of Directors,

George P. Hoyt

Secretary

Western Asset Managed Municipals Fund Inc.

Western Asset Municipal Partners Fund Inc.

Western Asset Intermediate Muni Fund Inc.

[    ], 2023

Table of Contents

INSTRUCTIONS FOR SIGNING PROXY CARDS

The following general rules for signing proxy cards may be of assistance to you and avoid the time and expense to the Funds involved in validating your vote if you fail to sign your proxy card properly.

1. Individual Accounts: Sign your name exactly as it appears in the registration on the proxy card.

2. Joint Accounts: Either party may sign, but the name of the party signing should conform exactly to a name shown in the registration.

3. All Other Accounts: The capacity of the individual signing the proxy card should be indicated unless it is reflected in the form of registration. For example:

Table of Contents

The information contained in this Proxy Statement/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 Proxy Statement/Prospectus is not an offer to sell these securities, and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED MARCH 17, 2023

PROXY STATEMENT/PROSPECTUS

            , 2023

PROXY STATEMENT FOR:

WESTERN ASSET MANAGED MUNICIPALS FUND INC.

WESTERN ASSET MUNICIPAL PARTNERS FUND INC.

WESTERN ASSET INTERMEDIATE MUNI FUND INC.

620 Eighth Avenue, 47th Floor

New York, New York 10018

888-777-0102

PROSPECTUS FOR:

WESTERN ASSET MANAGED MUNICIPALS FUND INC.

620 Eighth Avenue, 47th Floor

New York, New York 10018

888-777-0102

This combined Proxy Statement and Prospectus (the “Proxy Statement/Prospectus”) is being furnished in connection with the solicitation of proxies by the Board of Directors (the “Board”) of Western Asset Managed Municipals Fund Inc. (“MMU”), Western Asset Municipal Partners Fund Inc. (“MNP”) and Western Asset Intermediate Muni Fund Inc. (“SBI” and together with MMU and MNP, the “Funds”) for a Joint Special Meeting of Stockholders (the “Meeting”) for each Fund. The Meeting will be held Friday, [●], 2023 at [10:00 a.m.], Eastern Time. At the Meeting, stockholders of the Funds will be asked to consider and act upon separate proposals (“Proposals 1.A and 1.B”) to approve the mergers of each of MNP and SBI (each a “Target Fund” and collectively, the “Target Funds”) with and into MMU in accordance with the Maryland General Corporation Law (each a “Merger” and collectively, the “Mergers”), as described below:

If each Merger is approved, each share of common stock, par value $0.001 per share, of each Target Fund (respectively, the “MNP Common Shares,” the “SBI Common Shares” and collectively, the “Target Fund Common Shares”) would convert into an equivalent dollar amount (to the nearest $0.001) of full shares of common stock, par value $0.001 per share, of MMU (the “MMU Common Shares”), based on the net asset value of each Fund’s shares of common stock outstanding as of the close of trading on the NYSE on the business day immediately prior to the closing time of each respective Merger. MMU will not issue fractional MMU Common Shares to holders of Target Fund Common Shares. In lieu of issuing fractional shares, MMU will pay cash to each former holder of Target Fund Common Shares in an amount equal to the value of the fractional MMU Common Shares that the investor would otherwise have received in the applicable Merger. Although the MMU Common Shares received in each Merger will have the same total net asset value as the Target Fund Common Shares held immediately before the Mergers (disregarding fractional shares), their stock price on the New York Stock Exchange (“NYSE”) may be greater or less than that of the Target Fund Common Shares, based on current market prices existing at the time of the Merger. All MMU Common Shares currently issued and outstanding will remain issued and outstanding following the Merger.

Table of Contents

In addition, each of the Target Funds has a series of preferred stock outstanding: Variable Rate Demand Preferred Stock (“VRDPS”). MNP and MMU also each have Auction Rate Cumulative Preferred Stock (“ARPS”) outstanding.

Subject to approval of the respective Proposal by the stockholders of MNP, MNP’s ARPS will be redeemed in connection with—and prior to the closing of—its Merger, pursuant to the redemption terms outlined in the Articles Supplementary for the ARPS. Subject to the approval of either Proposal, MMU’s ARPS will be redeemed in connection with—and prior to the closing of—a Merger, pursuant to the redemption terms outlined in the Articles Supplementary for the ARPS. MNP and MMU each would provide notice of such a redemption to its ARPS holders following the approval of the Proposal at the Meeting and on a timeline consistent with the notice requirements in the Articles Supplementary for each series of ARPS and the Investment Company Act of 1940, as amended (the “1940 Act”).

With respect to the VRDPS, MMU will issue and deliver to each Target Fund newly issued shares of MMU’s VRDPS with the same aggregate liquidation preference and terms as SBI’s Series 1 VRDPS and MNP’s Series 1 VRDPS, respectively, issued and outstanding immediately before the date of the Merger. As the liquidation preference for the newly issued shares of MMU’s VRDPS that will replace the MNP’s Series 1 VRDPS will be equal to the liquidation preference of the existing MMU’s Series 1 VRDPS, MMU will issue a corresponding number of newly issued shares of MMU’s VRDPS so that the aggregate liquidation preference for the replaced MNP’s Series 1 VRDPS remains the same. In addition, MMU will also issue and deliver to each Target Fund newly issued shares of MMU’s VRDPS with the same aggregate liquidation preference as SBI’s ARPS and MNP’s ARPS, respectively, issued and outstanding as of December 31, 2022. Finally, MMU will issue additional VRDPS to replace its ARPS that are issued and outstanding as of December 31, 2022. The newly issued shares of MMU’s VRDPS would have equal liquidation preference per share as any other outstanding MMU’s VRDPS and equal priority with any other outstanding MMU’s VRDPS as to the payment of dividends and as to the distribution of assets upon dissolution, liquidation or winding up of the affairs of MMU. The accrual for SBI’s Series 1 VRDPS and MNP’s Series 1 VRDPS with respect to any accrued and unpaid dividends as of date of the Mergers would be assumed by MMU and would apply and be payable on an equivalent share-for-share basis and on the same dividend payment schedule to avoid any disruption to VRDPS holders. In connection with the Mergers but separate from the issuance of new shares of MMU’s VRDPS to each Target Fund’s current VRDPS holders and as a replacement for each Target Fund’s redeemed ARPS, MMU will issue additional shares of VRDPS to enable MMU to seek to approximately maintain its current level of leverage.

The Board of each Fund believes that the Mergers are in the best interests of stockholders and of each Fund. The Funds have substantially similar investment objectives, policies and strategies. The Mergers will result in more streamlined product offerings, allowing for more focused marketing and stockholder servicing efforts. Moreover, the combined Fund will likely benefit from economies of scale, as one set of fixed expenses would be spread over a larger asset base, as well as from enhanced market liquidity and may experience improved market price trading relative to net asset value (“NAV”).

At a meeting held on February 8 and 9, 2023, the Board of Directors of each Fund, including all of the Directors who are not “interested persons” of the Funds under the 1940 Act (the “Independent Directors”), unanimously approved an Agreement and Plan of Merger with respect to each Fund.

MNP was incorporated in Maryland on November 24, 1992; SBI was incorporated in Maryland on December 19, 1991; MMU was incorporated in Maryland on April 9, 1992. Each Target Fund is a closed-end, diversified management investment company and MMU is a closed-end, non-diversified management investment company. Each Fund is listed on the NYSE.

ii

Table of Contents

Comparison of Investment Objectives

Please see “Comparison of Investment Objectives, Principal Investment Strategies, and Principal Risks” in the Proxy Statement/Prospectus for a more complete comparison of the Funds’ investment objectives and policies.

Each Merger will be effected pursuant to an Agreement and Plan of Merger, a form of which is attached to this Proxy Statement/Prospectus as Appendix A. The material terms and conditions of each Agreement and Plan of Merger are summarized in this Proxy Statement/Prospectus. See “Proposals 1.A and 1.B—Information About the Proposed Mergers—Each Agreement and Plan of Merger.”

This Proxy Statement/Prospectus serves as a prospectus for MMU Common Shares under the Securities Act of 1933, as amended (the “Securities Act”), in connection with the issuance of MMU Common Shares in the Merger.

Assuming the holders of Target Fund Common Shares approve each Merger and all other conditions to the consummation of the Mergers are satisfied or waived, the Funds will jointly file articles of merger (the “Articles of Merger”) with the State Department of Assessments and Taxation of Maryland (the “SDAT”) with respect to each Merger. Each Merger will become effective when the SDAT accepts for record the Articles of Merger or at such later time, which may not exceed 30 days after the Articles of Merger are accepted for record, as specified in the Articles of Merger. The date when the Articles of Merger are accepted for record, or the later date, is referred to in this Proxy Statement/Prospectus as the “Closing Date.” Each Target Fund, as soon as practicable after the Closing Date, will withdraw its registration under the 1940 Act.

Each Merger is being structured as a tax-free reorganization for federal income tax purposes. See “Proposals 1.A and 1.B— Information About the Proposed Mergers—Federal Income Tax Consequences.” Stockholders should consult their tax advisors to determine the actual impact of the applicable Merger on them in light of their individual tax circumstances.

You should retain this Proxy Statement/Prospectus for future reference as it sets forth concisely information about MNP, SBI and MMU that you should know before voting on the Proposals described below.

A Statement of Additional Information (“SAI”) dated [ ], 2023, which contains additional information about the Mergers and the Funds, has been filed with the Securities and Exchange Commission (“SEC”). The SAI, as

iii

Table of Contents

well as MNP’s Annual Report to Stockholders for the Fiscal Year Ended November 30, 2022, filed on January 26, 2023 (accession no. 0001193125-23-015796), SBI’s Annual Report to Stockholders for the Fiscal Year Ended November 30, 2022, filed on January 30, 2023 (accession no. 0001193125-23-018467) and MMU’s Semi-Annual Report to Stockholders for the Six-Month Period Ended November 30, 2022, filed on January 27, 2023 (accession no. 0001193125-23-017174) and Annual Report to Stockholders for the Fiscal Year Ended May 31, 2022, filed on August 1, 2022 (accession no. 0001193125-22-208348), which highlight certain important information such as investment performance and expense and financial information, are incorporated by reference into this Proxy Statement/Prospectus. In addition, stockholder reports, proxy materials and other information concerning MNP (File No. 811-07362), SBI (File No. 811-6506) and MMU (File No. 811-06629) can be inspected at the NYSE. You may receive free of charge a copy of the SAI, or the annual report and semi-annual report for a Fund, by contacting MNP, SBI or MMU at 888-777-0102, by writing either Fund at the address listed above or by visiting our website at www.franklintempleton.com.

In addition, you can copy and review this Proxy Statement/Prospectus and the complete filing on Form N-14 containing the Proxy Statement/Prospectus (File No. 333-[    ]) and any of the above-referenced documents at the SEC’s Public Reference Room in Washington, DC. You may obtain information about the operation of the Public Reference Room by calling the SEC at 202-551-8090. Reports and other information about each Fund are available on the EDGAR Database on the SEC’s Internet site at www.sec.gov. You may also obtain copies of this information, after paying a duplicating fee, by electronic request at the following e-mail address: publicinfo@sec.gov, or by writing the SEC’s Public Reference Room, 100 F Street, N.E., Washington, DC 20549.

MNP’s Common Shares are listed on the NYSE under the symbol “MNP,” SBI’s Common Shares are listed on the NYSE under the symbol “SBI” and the MMU Common Shares are listed on the NYSE under the symbol “MMU.” If the Merger between either Target Fund and MMU is effected, or if both Mergers are effected, MMU will retain its ticker symbol “MMU.”

The information contained herein concerning each Fund has been provided by, and is included herein in reliance upon, the Fund.

The Securities and Exchange Commission has not approved or disapproved these securities nor passed upon the accuracy or adequacy of this Proxy Statement/Prospectus. Any representation to the contrary is a criminal offense.

iv

Table of Contents

TABLE OF CONTENTS

v

Table of Contents

PROPOSALS 1.A AND 1.B— TO APPROVE EACH OF THE MERGERS OF MNP AND SBI WITH AND INTO MMU IN ACCORDANCE WITH THE MARYLAND GENERAL CORPORATION LAW

Summary

This summary is qualified in its entirety by reference to the additional information contained elsewhere in this Proxy Statement/Prospectus and each Agreement and Plan of Merger, a form of which is attached to this Proxy Statement/Prospectus as Appendix A.

Proposed Mergers

The Board of each Fund believes that each Merger is in the best interests of stockholders of each Fund. The Target Funds and MMU have substantially similar primary investment objectives and substantially similar policies and strategies, which will allow Target Fund stockholders to continue to have exposure to municipal securities. Moreover, the combined Fund will likely benefit from economies of scale, as one set of fixed expenses would be spread over a larger asset base, as well as from enhanced market liquidity and additional opportunities for diversification. Furthermore, each Merger will result in more streamlined product offerings, allowing for more focused marketing and stockholder servicing efforts.

At a meeting held on February 8 and 9, 2023, the Boards of MNP, SBI and MMU, including all of the Independent Directors, unanimously approved the Agreement and Plan of Merger with respect to each Merger. As a result of the Mergers:

1

Table of Contents

Subject to approval of the respective Proposal by the stockholders of MNP, MNP’s ARPS will be redeemed in connection with—and prior to the closing of—its Merger, pursuant to the redemption terms outlined in the Articles Supplementary for the ARPS. Subject to the approval of either Proposal, MMU’s ARPS will be redeemed in connection with—and prior to the closing of—a Merger, pursuant to the redemption terms outlined in the Articles Supplementary for the ARPS. MNP and MMU each would provide notice of such a redemption to its ARPS holders following the approval of the Proposal at the Meeting and on a timeline consistent with the notice requirements in the Articles Supplementary for each series of ARPS and the 1940 Act.

Additionally, if either Merger is approved, MMU will institute a five basis point (0.05%) fee waiver of the investment management fee for a one-year period following the Mergers, or for as long as necessary to ensure such Funds only bear half of the Merger-related expenses.

Neither Merger is contingent upon the approval of the other Merger. If only one Merger is approved, that Merger will be consummated. If one or both Mergers is not approved, the applicable Fund or Funds will continue as separate investment companies, and each Board will consider such alternatives as it determines to be in the best interests of Fund stockholders, including re-proposing one or both Mergers, as applicable.

For the reasons set forth below in “Information About the Proposed Mergers-Reasons for the Mergers and Board Considerations,” the Boards of MNP, SBI and MMU, including all of the Independent Directors, have concluded that each Merger would be in the best interests of the applicable Funds, and that the interests of the holders of Target Fund Common Shares and MMU Common Shares would not be diluted as a result of the Merger. The Board of each Fund, therefore, is hereby submitting Proposals 1.A and 1.B to the holders of the respective Target Fund’s Common Shares and MMU Common Shares and recommends that stockholders of MNP, SBI and MMU vote “FOR” the applicable Merger(s).

Each Merger was approved by the Board of each Fund. Because the Merger of MNP into MMU has been approved by at least 75% of MNP’s “Continuing Directors,” as that term is defined in MNP’s charter, approval of the Merger requires the affirmative vote of a majority of votes entitled to be cast by holders of MNP Common Shares and holders of preferred stock of MNP (“MNP Preferred Shares”) (voting as a class). Additionally, because the Merger of SBI into MMU has been approved by at least 70% of SBI’s Board, approval of the Merger requires the affirmative vote of a majority of votes entitled to be cast by holders of SBI Common Shares and holders of preferred stock of SBI (“SBI Preferred Shares” and together with the MNP Preferred Shares, the “Target Fund Preferred Shares”) (voting as a class). Similarly, because the Merger has been approved by at least 75% of MMU’s “Continuing Directors” (as that term is defined in MMU’s charter) approval of each Merger requires the affirmative vote of a majority of votes entitled to be cast by holders of MMU Common Shares and holders of MMU preferred stock (“MMU Preferred Shares”) (voting as a class). See “Voting Information” below. If each Fund’s stockholders approve the Mergers at the Meeting on [●], 2023 (without the need to adjourn to solicit additional votes) and all other conditions to closing are satisfied (or waived), the Mergers are expected to take effect on or about [●], 2023, or such other date as the parties may agree.

Prior to completion of the Mergers, each Fund will receive an opinion of Simpson Thacher & Bartlett LLP to the effect that the applicable Merger will qualify as a tax-free reorganization for federal income tax purposes. Accordingly, for federal income tax purposes, (i) no gain or loss will generally be recognized by each Target Fund (except for consequences regularly attributable to a termination of its taxable year) or (subject to the following sentence) the holders of Target Fund Common Shares, MNP Series 1 VRDPS or SBI Series 1 VRDPS as a result of the Mergers, (ii) the aggregate tax basis of the MMU Common Shares (including fractional MMU Common Shares purchased by MMU) received by the holders of Target Fund Common Shares will be the same as the aggregate tax basis of the holders’ Target Fund Common Shares immediately prior to the completion of the applicable Merger, (iii) the aggregate tax basis of the MMU Series 1 VRDPS received by the holders of MNP

2

Table of Contents

Series 1 VRDPS or SBI Series 1 VRDPS will be the same as the aggregate tax basis of the holders’ MNP Series 1 VRDPS or SBI Series 1 VRDPS, as the case may be, immediately prior to the completion of the applicable Merger, (iv) a holder’s holding period for MMU Common Shares received pursuant to a Merger (including that of fractional MMU Common Shares purchased by MMU) will be determined by including the period for which such stockholder held Target Fund Common Shares converted pursuant to the Merger, provided that such shares were held by such stockholder as capital assets and (v) a holder’s holding period for MMU Series 1 VRDPS received pursuant to a Merger will be determined by including the period for which such stockholder held MNP Series 1 VRDPS or SBI Series 1 VRDPS, as the case may be, converted pursuant to the Merger, provided that such VRDPS were held by such stockholder as capital assets. Holders of Target Fund Common Shares may, however, recognize gain or loss with respect to cash such holders receive pursuant to a Merger in lieu of fractional shares. For more information about the federal income tax consequences of the Mergers, see “Information about the Proposed Mergers—Federal Income Tax Consequences” below.

Comparison of Investment Objectives, Principal Investment Strategies and Principal Risks

MNP’s primary investment objective is to provide a high level of current income which is exempt from regular federal income taxes, consistent with the preservation of capital. As a secondary investment objective, MNP intends to enhance portfolio value by purchasing tax-exempt securities that may appreciate in value relative to other similar obligations in the marketplace. SBI’s investment objective is to provide common stockholders a high level of current income exempt from regular federal income taxes, consistent with prudent investing. MMU’s investment objective is to seek as high a level of current income exempt from federal income tax as is consistent with the preservation of capital.

Under normal market conditions, at least 80% of MNP’s net assets will be invested in tax-exempt securities. Under normal market conditions, MNP invests substantially all of its assets in a diversified portfolio of tax-exempt securities that are rated investment grade at the time of purchase by at least one rating agency or, if unrated, determined to be of comparable credit quality by the subadviser, and that the subadviser believes do not involve undue risk to income or principal. MNP may invest up to 20% of its net assets in securities rated below investment grade at the time of purchase.

Under normal market conditions, SBI will invest at least 80% of its total assets in municipal obligations. In addition, under normal market conditions, SBI will invest at least 80% of its total assets in debt securities that are, at the time of investment, rated investment grade by a nationally recognized statistical rating organization or, if unrated, of equivalent quality as determined by the investment manager. 20% of SBI’s total assets may be invested in debt securities that are, at the time of investment, rated below investment grade by an NRSRO or, if unrated, of equivalent quality as determined by the investment manager.

Under normal market conditions, MMU will invest at least 80% of its total assets in municipal obligations rated investment grade at the time of investment. MMU may invest up to 20% of its total assets in municipal bonds rated below investment grade by a nationally recognized statistical rating organization or, if unrated, determined to be of equivalent quality by the investment manager.

While SBI maintains a dollar-weighted average effective maturity of between three and ten years, SBI’s sub-adviser may adjust the average maturity of SBI’s portfolio from time to time, depending on its assessment of the relative yields available on securities of different maturities and its expectations of future changes in interest rates. SBI’s sub-adviser may adjust the average maturity of SBI’s portfolio from time to time, depending on its assessment of the relative yields available on securities of different maturities and its expectations of future changes in interest rates. MNP’s sub-adviser is free to take full advantage of the entire range of maturities offered by tax-exempt securities and may adjust the average maturity of MNP’s portfolio from time to time, depending on its assessment of the relative yields available on securities of different maturities and its expectations of future changes in interest rates. MMU may invest in municipal obligations that have all types of interest rate payment and reset terms, including fixed rate, floating and variable rate, zero coupon, payment in kind and auction rate features.

3

Table of Contents

Each Fund is not intended to be a complete investment program, and there is no assurance that a Fund will achieve its objectives.

The preceding summary of the Funds’ investment objectives and certain policies should be considered in conjunction with the discussion below under “Comparison of Investment Objectives, Strategies and Principal Risks of Investing in the Funds—Investment Objectives,” “—Principal Investment Strategies,” “—Fundamental Investment Restrictions” and “—Risk Factors.”

Effect on Expenses

MNP currently pays an investment management fee to LMPFA, calculated daily and paid monthly, at an annual rate of 0.55% of its average weekly net assets. Both SBI and MMU currently pay LMPFA an investment management fee, calculated daily and paid monthly, at an annual rate of 0.55% of its average daily net assets.

If either Merger is approved, MMU will institute a five basis point (0.05%) fee waiver of the investment management fee for a one-year period following a Merger, or for as long as necessary to ensure such Funds only bear half of the merger-related expenses.

As of December 31, 2022, MNP had a total expense ratio of 3.10% of net assets, and SBI had a total expense ratio of 2.19% of net assets, whereas MMU had a total expense ratio of 2.60% of net assets. It is anticipated that MNP’s stockholders’ total expense ratio will decline by 0.65%, SBI’s stockholders’ total expense ratio will increase by 0.26% and MMU’s stockholders’ total expense ratio will decline by 0.15% if both Mergers are approved.

Fee Table and Expense Example

The table below (1) compares the estimated fees and expenses of each Fund, as of December 31, 2022, and (2) shows the estimated fees and expenses of the combined Fund, on a pro forma basis, as if both Mergers occurred on December 31, 2022.

The estimates are based on the contracts and agreements in effect as of December 31, 2022 and reflect the operating expense accrual rates on that date, which are based on each Fund’s net assets as of December 31, 2022. Accordingly, the actual fees and expenses of each Fund and the combined Fund as of the Closing Date of the Mergers may differ from those reflected in the tables below due to changes in net assets from those at such dates. No amount of any prior fee waiver or expense reimbursement to MNP, SBI or MMU may be recovered by any person.

Changes in net assets may result from market appreciation or depreciation and other factors occurring between December 31, 2022 and the Closing Date of the Merger. As a general matter, changes (positive or negative) in a Fund’s expense ratio resulting from fluctuations in the Fund’s net assets will be borne by the stockholders of that Fund and the combined Fund. For information concerning the net assets of each Fund as of December 31, 2022, please see “Capitalization.”

The estimated expenses of MNP, SBI and MMU as of December 31, 2022 and pro forma expenses following the proposed Mergers are set forth below. The percentages in the table below are percentages of the Funds’ net assets attributable to their Common Shares.

4

Table of Contents

Fee Table (MNP and MMU Merger)

Fee Table (SBI and MMU Merger)

5

Table of Contents

Fee Table (both Mergers)

Example (MNP and MMU Merger)

The following example helps you compare the costs of investing in the Funds’ Common Shares with the costs of investing in other funds. The example assumes that you invest $1,000 in each Fund’s Common Shares for the periods shown, that your investment has a 5% return each year, that you reinvest all distributions and dividends and that the Funds’ operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Example (SBI and MMU Merger)

The following example helps you compare the costs of investing in the Funds’ Common Shares with the costs of investing in other funds. The example assumes that you invest $1,000 in each Fund’s Common Shares for the periods shown, that your investment has a 5% return each year, that you reinvest all distributions and dividends and that the Funds’ operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Example (both Mergers)

The following example helps you compare the costs of investing in the Funds’ Common Shares with the costs of investing in other funds. The example assumes that you invest $1,000 in each Fund’s Common Shares

6

Table of Contents

for the periods shown, that your investment has a 5% return each year, that you reinvest all distributions and dividends and that the Funds’ operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

7

Table of Contents

COMPARISON OF INVESTMENT OBJECTIVES, STRATEGIES AND PRINCIPAL RISKS OF INVESTING IN THE FUNDS

The following charts list the investment objectives, principal investment policies and fundamental investment restrictions of MNP and SBI, respectively, compares them to MMU and describes the principal differences between the Target Funds’ respective policies and MMU’s policies. The charts provide MNP, SBI and MMU stockholders with a means of comparing the investment objectives, policies and strategies of the Funds.

Comparison of MNP and MMU Investment Objectives and Strategies

8

Table of Contents

9

Table of Contents

10

Table of Contents

11

Table of Contents

12

Table of Contents

Comparison of SBI and MMU Investment Objectives and Strategies

13

Table of Contents

14

Table of Contents

15

Table of Contents

16

Table of Contents

17

Table of Contents

18

Table of Contents

Comparison of MNP and MMU Fundamental Investment Restrictions

19

Table of Contents

20

Table of Contents

21

Table of Contents

Comparison of SBI and MMU Fundamental Investment Restrictions

22

Table of Contents

23

Table of Contents

Risk Factors

There is no assurance that MNP, SBI or MMU will meet their investment objectives. You may lose money on your investment in any of the Funds. The value of each Fund’s shares may go up or down, sometimes rapidly

24

Table of Contents

and unpredictably. Market conditions, financial conditions of issuers represented in each Fund’s portfolio, investment strategies, portfolio management and other factors affect the volatility of each Fund’s shares. An investment in a Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency.

The following section includes a summary of the principal risks of investing in MMU. Except as described below, your investment in MNP or SBI is subject to the same risks.

Investment and Market Risk

An investment in MMU is subject to investment risk, including the possible loss of the entire amount that you invest. Your investment in MMU Common Shares represents an indirect investment in the fixed income securities and other investments owned by MMU, most of which could be purchased directly. The value of the MMU’s portfolio securities may move up or down, sometimes rapidly and unpredictably. At any point in time, your MMU Common Shares may be worth less than your original investment, even after taking into account the reinvestment of MMU dividends and distributions.

Interest Rate Risk

MMU expects that under normal market circumstances at least 80% of its assets will consist of investment grade tax-exempt securities, the market value of which generally varies inversely with changes in prevailing interest rates. The market value of MMU’s investments will change in response to changes in interest rates and other factors. During periods of declining interest rates, the values of fixed-income securities generally rise. Conversely, during periods of rising interest rates, the values of such securities generally decline. The magnitude of these fluctuations is generally greater for securities with longer maturities. The subadviser’s judgment about interest rate trends may prove to be incorrect.

Tax-Exempt Securities Risk

In general, the secondary market for tax-exempt securities is less liquid than that for taxable fixed-income securities. Consequently, the ability of MMU to buy and sell tax-exempt securities may, at any particular time and with respect to any particular securities, be limited. The amount of information about the financial condition of an issuer of tax-exempt securities may not be as extensive as information about corporations whose securities are publicly traded. Obligations of issuers of tax-exempt securities may be subject to the provisions of bankruptcy, insolvency and the United States Bankruptcy Code and applicable state laws, which could limit the ability of MMU to recover payments of principal or interest on such securities.

Certain tax-exempt securities which may be held by MMU may permit the issuer at its option to “call,” or redeem, its securities. If an issuer were to redeem tax-exempt securities held by MMU during a time of declining interest rates, MMU may realize a capital loss on its investment if the security was purchased at a premium and may not be able to reinvest the proceeds in tax-exempt securities providing as high a level of investment return as the securities redeemed.

Municipal Securities Risk

Liquidity in the municipal securities market may vary from time to time. At times of decreased liquidity, the ability of MMU to buy and sell municipal securities may, with respect to any particular securities, be limited. The amount of information about the financial condition of an issuer of municipal securities may not be as extensive as information about corporations whose securities are publicly traded, and MMU’s performance may therefore be more dependent on the sub-adviser’s analytical abilities than if MMU were to invest in stocks or taxable bonds. The secondary market for municipal securities, particularly the below investment grade municipal securities in which MMU may invest, also tends to be less developed or liquid than many other securities markets, which may adversely affect MMU’s ability to sell its municipal securities at attractive prices.

25

Table of Contents

Obligations of issuers of municipal securities may be subject to the provisions of bankruptcy, insolvency and the United States Bankruptcy Code and applicable state laws, which could limit the ability of MMU to recover payments of principal or interest on such securities.

Certain municipal securities which may be held by MMU may permit the issuer at its option to “call,” or redeem, its securities. If an issuer were to redeem municipal securities held by MMU during a time of declining interest rates, MMU may realize a capital loss on its investment if the security was purchased at a premium and may not be able to reinvest the proceeds in municipal securities providing as high a level of investment return as the securities redeemed.

Inverse Floating Rate Securities and TOBs Risk

Subject to certain limitations, MMU may invest in inverse floating rate securities. Typically, inverse floating rate securities represent beneficial interests in a special purpose trust (sometimes called a “tender option bond trust”) formed by a third party sponsor for the purpose of holding municipal bonds purchased from MMU or from another third party. An investment in an inverse floating rate security may involve greater risk than an investment in a fixed-rate bond. Because changes in the interest rate on the underlying security or index inversely affect the residual interest paid on the inverse floating rate security, the value of an inverse floating rate security is generally more volatile than that of a fixed-rate bond.

Inverse floating rate securities have interest rate adjustment formulas which generally reduce or, in the extreme, eliminate the interest paid to MMU when short-term interest rates rise, and increase the interest paid to MMU when short-term interest rates fall. Inverse floating rate securities have varying degrees of liquidity, and the market for these securities is relatively volatile. These securities tend to underperform the market for fixed-rate bonds in a rising interest rate environment, but tend to outperform the market for fixed-rate bonds when interest rates decline. Shifts in long-term interest rates may, however, alter this tendency.

During times of reduced market liquidity, such as at the present, MMU may not be able to sell municipal securities readily at prices reflecting the values at which the securities are carried on MMU’s books. Sales of large blocks of municipal securities by market participants, such as MMU, that are seeking liquidity can further reduce municipal security prices in an illiquid market. MMU may seek to make sales of large blocks of municipal securities as part of its investment strategy or it may be required to raise cash to re-collateralize, unwind or “collapse” tender option bond trusts that issued inverse floating rate securities to MMU or to make payments to such trusts to enable them to pay for tenders of the short-term securities they have issued if the remarketing agents for those municipal securities are unable to sell the short-term securities in the marketplace to other buyers (typically tax-exempt money market funds). MMU’s potential exposure to losses related to or on inverse floating rate securities may increase beyond the value of MMU’s inverse floater investments as MMU may potentially be liable to fulfill all amounts owed to holders of the floating rate certificates.

Although volatile, inverse floating rate securities typically offer the potential for yields exceeding the yields available on fixed-rate bonds with comparable credit quality, coupon, call provisions and maturity. These securities usually permit the investor to convert the floating rate to a fixed rate (normally adjusted downward), and this optional conversion feature may provide a partial hedge against rising rates if exercised at an opportune time.

Investment in inverse floating rate securities may amplify the effects of MMU’s use of leverage. Any economic effect of leverage through MMU’s purchase of inverse floating rate securities will create an opportunity for increased MMU Common Shares net income and returns, but may also result in losses if the cost of leverage exceeds the return on the inverse floating rate securities purchased by MMU.

TOB transactions expose MMU to leverage and credit risk, and generally involve greater risk than investments in fixed rate municipal bonds, including the risk of loss of principal. The interest payments that

26

Table of Contents

MMU would typically receive on inverse floaters acquired in such transactions vary inversely with short-term interest rates and will be reduced (and potentially eliminated) when short-term interest rates increase. Inverse floaters will generally underperform the market for fixed rate municipal securities when interest rates rise. The value and market for inverse floaters can be volatile, and inverse floaters can have limited liquidity. Investments in inverse floaters issued in TOB transactions are derivative instruments and, therefore, are also subject to the risks generally applicable to investments in derivatives.

Insurance Risk

MMU may purchase municipal securities that are secured by insurance, bank credit agreements or escrow accounts. The credit quality of the companies that provide such credit enhancements will affect the value of those securities. Certain significant providers of insurance for municipal securities have recently incurred significant losses as a result of exposure to sub-prime mortgages and other lower credit quality investments that have experienced recent defaults or otherwise suffered extreme credit deterioration. As a result, such losses have reduced the insurers’ capital and called into question their continued ability to perform their obligations under such insurance if they are called upon to do so in the future. While an insured municipal security will typically be deemed to have the rating of its insurer, if the insurer of a municipal security suffers a downgrade in its credit rating or the market discounts the value of the insurance provided by the insurer, the rating of the underlying municipal security will be more relevant and the value of the municipal security would more closely, if not entirely, reflect such rating. In such a case, the value of insurance associated with a municipal security would decline, and the insurance may not add any value. The insurance feature of a municipal security does not guarantee the full payment of principal and interest through the life of an insured obligation, the market value of the insured obligation or the net asset value of the MMU Common Shares represented by such insured obligation.

Leverage Risk

The value of your investment may be more volatile due to MMU’s leveraged capital structure and use of instruments that have a leveraging effect on MMU’s portfolio. MMU may also have to sell assets at inopportune times to satisfy its obligations created by the use of leverage or derivatives. The use of leverage is considered to be a speculative investment practice and may result in the loss of a substantial amount, and possibly all, of MMU’s assets.

Special Risks Related to Municipal Securities

MMU may invest in municipal leases and certificates of participation in such leases. Municipal leases and certificates of participation involve special risks not normally associated with general obligations or revenue bonds. Leases and installment purchase or conditional sale contracts (which normally provide for title to the leased asset to pass eventually to the governmental issuer) have evolved as a means for governmental issuers to acquire property and equipment without meeting the constitutional and statutory requirements for the issuance of debt. The debt issuance limitations are deemed to be inapplicable because of the inclusion in many leases or contracts of “non-appropriation” clauses that relieve the governmental issuer of any obligation to make future payments under the lease or contract unless money is appropriated for such purpose by the appropriate governmental body on a yearly or other periodic basis. In addition, such leases or contracts may be subject to the temporary abatement of payments in the event the governmental issuer is prevented from maintaining occupancy of the leased premises or utilizing the leased equipment. Although the obligations may be secured by the leased equipment or facilities, the disposition of the property in the event of non-appropriation or foreclosure might prove difficult, time consuming and costly, and may result in a delay in recovering or the failure to fully recover MMU’s original investment. In the event of non-appropriation, the issuer would be in default and taking ownership of the assets may be a remedy available to MMU, although MMU does not anticipate that such a remedy would normally be pursued. To the extent that MMU invests in unrated municipal leases or participates in such leases, the credit quality rating and risk of cancellation of such unrated leases will be monitored on an ongoing basis. Certificates of participation, which represent interests in unmanaged pools of municipal leases or

27

Table of Contents

installment contracts, involve the same risks as the underlying municipal leases. In addition, MMU may be dependent upon the municipal authority issuing the certificates of participation to exercise remedies with respect to the underlying securities. Certificates of participation also entail a risk of default or bankruptcy, both of the issuer of the municipal lease and also the municipal agency issuing the certificate of participation.

Alternative Minimum Tax and Taxable Income Risk

MMU will qualify to pay “exempt-interest dividends,” which are exempt from regular U.S. federal income tax, for any taxable year only if at least 50% of the value of its assets, as of the close of each quarter of the taxable year, consists of state or local obligations described in Section 103(a) of the Code. Assuming that MMU qualifies to pay exempt-interest dividends, it is anticipated that certain of MMU’s distributions will nevertheless constitute taxable income. Moreover, a portion of MMU’s exempt-interest dividends may be subject to federal alternative minimum tax, and all or a portion of such dividends may be subject to state and local taxation.

A portion of MMU’s distributions may be taxable to holders of MMU Common Shares. In particular, MMU may use a variety of derivative instruments and may sell certain fixed-income securities short including, but not limited to, U.S. Treasuries, for investment and/or hedging purposes. To the extent that MMU utilizes these strategies MMU could generate taxable income and gains. Distributions of any capital gain or other taxable income (including gains and “market discount” realized by MMU on the sale of municipal securities) will be taxable to holders of MMU Common Shares. MMU may not be a suitable investment for investors subject to the federal alternative minimum tax or who would become subject to such tax by investing in MMU. The suitability of an investment in MMU Common Shares will depend upon a comparison of the after tax yield likely to be provided from MMU with that from comparable tax-exempt investments not subject to the alternative minimum tax, and from comparable fully taxable investments, in light of each such investor’s tax position. Special considerations apply to corporate investors.

Certain provisions of the Code relating to the issuance of municipal obligations impose restrictions on the volume of municipal obligations qualifying for federal tax exemption. One effect of these provisions could be to increase the cost of the municipal securities available for purchase by MMU and thus reduce available yield. Legislative proposals that may further restrict or eliminate the federal income tax exemption for interest on municipal obligations may be introduced in the future. The value of MMU’s investments and its net asset value may be adversely affected by changes in tax rates and policies. Because interest income from municipal securities normally is not subject to regular federal income taxation, the attractiveness of municipal securities in relation to other investment alternatives is affected by changes in federal income tax rates or changes in the tax-exempt status of interest income from municipal securities. Any proposed or actual changes in such rates or exempt status, therefore, can significantly affect the demand for and supply, liquidity and marketability of municipal securities. This could in turn affect MMU’s net asset value and ability to acquire and dispose of municipal securities at desirable yield and price levels.

Below Investment Grade (High Yield or Junk Bond) Securities Risk

MMU may invest up to 20% of its assets in municipal obligations of below investment grade quality. High yield debt securities are generally subject to greater credit risks than higher-grade debt securities, including the risk of default on the payment of interest or principal. High yield debt securities are considered speculative, typically have lower liquidity and are more difficult to value than higher grade bonds. High yield debt securities tend to be volatile and more susceptible to adverse events, credit downgrades and negative sentiments and may be difficult to sell at a desired price, or at all, during periods of uncertainty or market turmoil.

Credit Crisis Liquidity and Volatility Risk

The markets for credit instruments, including fixed income securities, have experienced periods of extreme illiquidity and volatility. General market uncertainty and consequent repricing risk have led to market imbalances

28

Table of Contents

of sellers and buyers, which in turn have also resulted in significant valuation uncertainties in a variety of debt securities, including certain fixed income securities. These conditions resulted, and in many cases continue to result in greater volatility, less liquidity, widening credit spreads and a lack of price transparency, with many debt securities remaining illiquid and of uncertain value. During times of reduced market liquidity, MMU may not be able to sell securities readily at prices reflecting the values at which the securities are carried on MMU’s books. Sales of large blocks of securities by market participants, such as MMU, that are seeking liquidity can further reduce security prices in an illiquid market. These market conditions may make valuation of some of MMU’s securities uncertain and/or result in sudden and significant valuation increases or decreases in its holdings. Illiquidity and volatility in the credit markets may directly and adversely affect the setting of dividend rates on the MMU Common Shares.

Liquidity Risk

MMU may invest, without limitation, in illiquid securities (similar to SBI), while MNP, as a matter of operating policy, does not invest in illiquid securities. Illiquid securities are securities that cannot be disposed of within seven days in the ordinary course of business at approximately the value at which MMU has valued the securities. Liquidity risk exists when particular investments are difficult to sell. Securities may become illiquid after purchase by MMU, particularly during periods of market turmoil. When MMU holds illiquid investments, the portfolio may be harder to value, especially in changing markets, and if MMU is forced to sell these investments in order to segregate assets or for other cash needs, MMU may suffer a loss.

Government Intervention in Financial Markets Risk

The instability in the financial markets has led the U.S. government and foreign governments to take a number of unprecedented actions designed to support certain financial institutions and segments of the financial markets that have experienced extreme volatility, and in some cases a lack of liquidity. U.S. federal and state governments and foreign governments, their regulatory agencies or self regulatory organizations may take additional actions that affect the regulation of the securities in which MMU invests, or the issuers of such securities, in ways that are unforeseeable. Issuers of corporate fixed income securities might seek protection under the bankruptcy laws. Legislation or regulation may also change the way in which MMU itself is regulated. Such legislation or regulation could limit or preclude MMU’s ability to achieve its investment objectives. Western Asset will monitor developments and seek to manage MMU’s portfolio in a manner consistent with achieving MMU’s investment objectives, but there can be no assurance that it will be successful in doing so.

Derivatives Risk

MMU may utilize a variety of derivative instruments for investment or risk management purposes, such as options, futures contracts, swap agreements and credit default swaps. Using derivatives can increase Fund losses and reduce opportunities for gains when market prices, interest rates, currencies, or the derivatives themselves behave in a way not anticipated by MMU. Using derivatives also can have a leveraging effect and increase Fund volatility. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Derivatives may not be available at the time or price desired, may be difficult to sell, unwind or value, and the counterparty may default on its obligations to MMU. Derivatives are generally subject to the risks applicable to the assets, rates, indices or other indicators underlying the derivative. The value of a derivative may fluctuate more than the underlying assets, rates, indices or other indicators to which it relates. Use of derivatives may have different tax consequences for MMU than an investment in the underlying security, and those differences may affect the amount, timing and character of income distributed to shareholders. The U.S. government and foreign governments are in the process of adopting and implementing regulations governing derivatives markets, including mandatory clearing of certain derivatives, margin and reporting requirements. The ultimate impact of the regulations remains unclear. Additional regulation of derivatives may make derivatives more costly, limit their availability or utility, otherwise adversely affect their performance or disrupt markets.

29

Table of Contents

Effective August 19, 2022, MMU began operating under Rule 18f-4 under the 1940 Act which, among other things, governs the use of derivative investments and certain financing transactions (e.g. reverse repurchase agreements) by registered investment companies. Among other things, Rule 18f-4 requires funds that invest in derivative instruments beyond a specified limited amount to apply a value at risk (VaR) based limit to their use of certain derivative instruments and financing transactions and to adopt and implement a derivatives risk management program. A fund that uses derivative instruments in a limited amount is not subject to the full requirements of Rule 18f-4. Compliance with Rule 18f-4 by MMU could, among other things, make derivatives more costly, limit their availability or utility, or otherwise adversely affect their performance. Rule 18f-4 may limit the Fund’s ability to use derivatives as part of its investment strategy.

Lending Securities

The risks in lending portfolio securities, as with other extensions of credit, consist of possible delays in recovery of the securities or possible loss of rights in the collateral should the borrower fail financially. Although voting rights, or rights to consent, with respect to the loaned securities pass to the borrower, MMU retains the right to call the loans at any time on reasonable notice, and it will do so in order that the securities may be voted by MMU if the holders of such securities are asked to vote upon or consent to matters materially affecting the investment. MMU also may call such loans in order to sell the securities involved. Unlike MMU and SBI, MNP typically does not engage in the practice of lending portfolio securities, although it has the ability to do so.

Counterparty Risk

MMU may enter into transactions with counterparties that become unable or unwilling to fulfill their contractual obligations. There can be no assurance that any such counterparty will not default on its obligations to MMU. In the event of a counterparty default, MMU may be hindered or delayed in exercising rights against a counterparty and may experience significant losses. To the extent that MMU enters into multiple transactions with a single or small set of counterparties, MMU will be subject to increased counterparty risk.

Credit Risk

If an issuer or guarantor of a security held by MMU or a counterparty to a financial contract with MMU defaults or its credit is downgraded, or is perceived to be less creditworthy, or if the value of the assets underlying a security declines, the value of your investment will typically decline. Changes in actual or perceived creditworthiness may occur quickly. MMU could be delayed or hindered in its enforcement of rights against an issuer, guarantor or counterparty. Subordinated securities are more likely to suffer a credit loss than non-subordinated securities of the same issuer and will be disproportionately affected by a default, downgrade or perceived decline in creditworthiness.

Prepayment Risk

Prepayments may cause losses on securities purchased at a premium. At times, some of the securities in which MMU may invest may have higher than market interest rates and therefore may be purchased at a premium above their par value. Unscheduled prepayments, which are made at par, may cause MMU to experience a loss equal to any unamortized premium. In addition, a reduction in prepayments may increase the effective maturities of these securities, subjecting them to a greater risk of decline in market value in response to rising interest rates than traditional debt securities, and, therefore, potentially increasing the volatility of MMU.

Inflation/Deflation Risk

Inflation risk is the risk that the value of certain assets or income from MMU’s investments will be worth less in the future as inflation decreases the value of money. As inflation increases, the real value of the MMU Common Shares and distributions on the MMU Common Shares can decline. In addition, during any periods of

30

Table of Contents

rising inflation, the dividend rates or borrowing costs associated with MMU’s use of leverage would likely increase, which would tend to further reduce returns to stockholders. Deflation risk is the risk that prices throughout the economy decline over time—the opposite of inflation. Deflation may have an adverse effect on the creditworthiness of issuers and may make issuer defaults more likely, which may result in a decline in the value of MMU’s portfolio.

Market Events Risk

The market values of securities or other assets will fluctuate, sometimes sharply and unpredictably, due to changes in general market conditions, overall economic trends or events, governmental actions or intervention, actions taken by the U.S. Federal Reserve or foreign central banks, market disruptions caused by trade disputes or other factors, political developments, investor sentiment, the global and domestic effects of a pandemic, and other factors that may or may not be related to the issuer of the security or other asset. Economies and financial markets throughout the world are increasingly interconnected. Economic, financial or political events, trading and tariff arrangements, public health events, terrorism, natural disasters and other circumstances in one country or region could have profound impacts on global economies or markets. As a result, whether or not MMU invests in securities of issuers located in or with significant exposure to the countries directly affected, the value and liquidity of MMU’s investments may be negatively affected.

The rapid and global spread of a highly contagious novel coronavirus respiratory disease, designated COVID-19, first detected in China in December 2019, has resulted in extreme volatility in the financial markets and severe losses; reduced liquidity of many instruments; restrictions on international and, in some cases, local travel, significant disruptions to business operations (including business closures); strained healthcare systems; disruptions to supply chains, consumer demand and employee availability; and widespread uncertainty regarding the duration and long-term effects of this pandemic. Some sectors of the economy and individual issuers have experienced particularly large losses. In addition, the COVID-19 pandemic may result in a sustained economic downturn or a global recession, domestic and foreign political and social instability, damage to diplomatic and international trade relations and increased volatility and/or decreased liquidity in the securities markets. The ultimate economic fallout from the pandemic, and the long-term impact on economies, markets, industries and individual issuers, are not known. Certain risks, such as interest rate risk, credit risk, liquidity risk and counterparty risk, may be heightened as a result of such market events. The U.S. government and the Federal Reserve, as well as certain foreign governments and central banks, are taking extraordinary actions to support local and global economies and the financial markets in response to the COVID-19 pandemic, including by pushing interest rates to very low levels. This and other government intervention into the economy and financial markets to address the COVID-19 pandemic may not work as intended, particularly if the efforts are perceived by investors as being unlikely to achieve the desired results. The COVID-19 pandemic could adversely affect the value and liquidity of MMU’s investments and negatively impact MMU’s performance. In addition, the outbreak of COVID-19, and measures taken to mitigate its effects, could result in disruptions to the services provided to MMU by its service providers.

Anti-Takeover Provisions Risk

MMU’s Charter and Bylaws include provisions that are designed to limit the ability of other entities or persons to acquire control of MMU for short-term objectives, including by converting MMU to open-end status or changing the composition of the Board, that may be detrimental to MMU’s ability to achieve its primary investment objective. Such provisions may limit the ability of shareholders to sell their shares at a premium over prevailing market prices by discouraging a third party from seeking to obtain control of MMU. There can be no assurance, however, that such provisions will be sufficient to deter activist investors that seek to cause MMU to take actions that may not be aligned with the interests of long-term shareholders.

31

Table of Contents

Portfolio Turnover Risk

Changes to the investments of MMU may be made regardless of the length of time particular investments have been held. A high portfolio turnover rate may result in increased transaction costs for MMU in the form of increased dealer spreads and other transactional costs, which may have an adverse impact on performance. The portfolio turnover rate of MMU will vary from year to year, as well as within a year.

Management Risk

MMU is subject to management risk because it is an actively managed investment portfolio. The subadviser and each individual portfolio manager will apply investment techniques and risk analyses in making investment decisions for MMU, but there can be no guarantee that these will produce the desired results.

Market Price Discount from Net Asset Value Risk

Shares of closed-end investment companies frequently trade at a discount from their net asset value. This risk is separate and distinct from the risk that MMU’s net asset value could decrease as a result of its investment activities and may be a greater risk to investors expecting to sell their MMU Common Shares in a relatively short period following completion of this offering. Whether investors will realize gains or losses upon the sale of the MMU Common Shares will depend not upon MMU’s net asset value but upon whether the market price of the MMU Common Shares at the time of sale is above or below the investor’s purchase price for the MMU Common Shares.

Because the market price of the MMU Common Shares will be determined by factors such as relative supply of and demand for the MMU Common Shares in the market, general market and economic conditions and other factors beyond the control of MMU, MMU cannot predict whether the MMU Common Shares will trade at, above or below net asset value or at, above or below the initial public offering price. MMU’s Common Shares is designed primarily for long term investors and you should not view MMU as a vehicle for trading purposes.

Temporary Defensive Strategies Risk

When the manager believes a temporary defensive posture in the market is warranted (e.g., times when, in the manager’s opinion, temporary imbalances of supply and demand or other temporary dislocations in the municipal obligations market adversely affect the price at which municipal obligations are available), and in order to keep cash on hand fully invested, MMU may temporarily invest to a substantial degree in high quality, short-term municipal obligations. If these high-quality, short-term municipal obligations are not available or, in the manager’s judgment, do not afford sufficient protection against adverse market conditions, MMU may invest in the following taxable securities: obligations of the U.S. Government and its agencies or instrumentalities; other debt securities rated within the four highest categories by an NRSRO; commercial paper rated in the highest category by an NRSRO; certificates of deposit, time deposits and bankers’ acceptances; or repurchase agreements with respect to any of the foregoing investments or any other fixed-income securities that the manager considers consistent with such strategy. To the extent MMU invests in taxable securities, MMU will not at such times be able to achieve its investment objective of earning income that is exempt from regular federal income taxes.

LIBOR Risk

MMU’s investments, payment obligations, and financing terms may be based on floating rates, such as the London Interbank Offered Rate, or “LIBOR,” which is the offered rate for short-term Eurodollar deposits between major international banks. In 2017, the U.K. Financial Conduct Authority (“FCA”) announced its intention to cease compelling banks to provide the quotations needed to sustain LIBOR after 2021. ICE Benchmark Administration, the administrator of LIBOR, ceased publication of most LIBOR settings on a

32

Table of Contents

representative basis at the end of 2021 and is expected to cease publication of a majority of U.S. dollar LIBOR settings on a representative basis after June 30, 2023. In addition, global regulators have announced that, with limited exceptions, no new LIBOR-based contracts should be entered into beginning in 2022. Actions by regulators have resulted in the establishment of alternative reference rates to LIBOR in most major currencies. Various financial industry groups have been planning for the transition away from LIBOR, but there remains uncertainty regarding the nature of any replacement rate and the impact of the transition from LIBOR on MMU’s transactions and the financial markets generally. The transition away from LIBOR may lead to increased volatility and illiquidity in markets that rely on LIBOR and may adversely affect MMU’s performance. The transition may also result in a reduction in the value of certain LIBOR-based investments held by MMU or reduce the effectiveness of related transactions such as hedges. Any such effects of the transition away from LIBOR, as well as other unforeseen effects, could result in losses for MMU. Since the usefulness of LIBOR as a benchmark could also deteriorate during the transition period, effects could occur at any time.

Operational Risk

The valuation of MMU’s investments may be negatively impacted because of the operational risks arising from factors such as processing errors and 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 or trading counterparties. It is not possible to identify all of the operational risks that may affect MMU or to develop processes and controls that completely eliminate or mitigate the occurrence of such failures. MMU and its shareholders could be negatively impacted as a result.

Cybersecurity Risk

Cybersecurity incidents, both intentional and unintentional, may allow an unauthorized party to gain access to Fund assets, Fund or proprietary information, cause MMU, LMPFA and Western Asset and/or their service providers to suffer data breaches, data corruption or loss of operational functionality or prevent Fund investors from purchasing, redeeming or exchanging shares or receiving distributions. MMU, LMPFA and Western Asset have limited ability to prevent or mitigate cybersecurity incidents affecting third party service providers, and such third party service providers may have limited indemnification obligations to MMU or LMPFA. Cybersecurity incidents may result in financial losses to MMU and its shareholders, and substantial costs may be incurred in an effort to prevent or mitigate future cybersecurity incidents. Issuers of securities in which MMU invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers experience cybersecurity incidents.

33

Table of Contents

INFORMATION ABOUT THE PROPOSED MERGERS

The Agreement and Plan of Merger

The following is a summary of the material terms and conditions of each Agreement and Plan of Merger. This summary is qualified in its entirety by reference to the Form of Agreement and Plan of Merger attached as Appendix A to this Proxy Statement/Prospectus. Under the applicable Agreement and Plan of Merger, MNP and SBI will merge with and into MMU on the Closing Date.

As a result of the Mergers and on the Closing Date:

Each of MNP and SBI will then:

Each outstanding Target Fund Common Share will be converted into an equivalent dollar amount (to the nearest one tenth of one cent) of full MMU Common Shares, based on the net asset value of each Target Fund’s Common Shares outstanding as of the close of trading on the NYSE on the business day immediately prior to the closing time of each respective Merger. No fractional MMU Common Shares will be issued to the holders of Target Fund Common Shares. In lieu thereof, MMU will pay cash to each former holder of Target Fund Common Shares in an amount equal to the value of the fractional MMU Common Shares that the investor would otherwise have received in the applicable Merger.

In addition, MMU will issue and deliver to each Target Fund newly issued shares of MMU’s VRDPS with the same aggregate liquidation preference and terms as SBI’s Series 1 VRDPS and MNP’s Series 1 VRDPS, respectively, issued and outstanding immediately before the date of the Merger. As the liquidation preference for the newly issued shares of MMU’s VRDPS that will replace the MNP’s Series 1 VRDPS will be equal to the liquidation preference of the existing MMU’s Series 1 VRDPS, MMU will issue a corresponding number of newly issued shares of MMU’s VRDPS so that the aggregate liquidation preference for the replaced MNP’s Series 1 VRDPS remains the same. In addition, MMU will also issue and deliver to each Target Fund newly issued shares of MMU’s VRDPS with the same aggregate liquidation preference as SBI’s ARPS and MNP’s ARPS, respectively, issued and outstanding as of December 31, 2022. Finally, MMU will issue additional VRDPS to replace its ARPS that are issued and outstanding as of December 31, 2022. The newly issued shares of MMU’s VRDPS would have equal liquidation preference per share as any other outstanding MMU’s VRDPS and equal priority with any other outstanding MMU’s VRDPS as to the payment of dividends and as to the distribution of assets upon dissolution, liquidation or winding up of the affairs of MMU. The accrual for SBI’s Series 1 VRDPS and MNP’s Series 1 VRDPS with respect to any accrued and unpaid dividends as of date of the Mergers would be assumed by MMU and would apply and be payable on an equivalent share-for-share basis and on the same dividend payment schedule to avoid any disruption to VRDPS holders.

No sales charge or fee of any kind will be charged to holders of Target Fund Common Shares in connection with their receipt of MMU Common Shares in the applicable Merger.

From and after the Closing Date, MMU will possess all of the properties, assets, rights, privileges and powers and shall be subject to all of the restrictions, liabilities, obligations, disabilities and duties of each Target Fund, all as provided under Maryland law.

34

Table of Contents

Under Maryland law, stockholders of a corporation whose shares are traded publicly on a national securities exchange, such as the Funds’ Common Shares, are not entitled to demand the fair value of their shares upon a merger; therefore, the holders of the Funds’ Common Shares will be bound by the terms of the Merger, if approved. However, any holder of either Fund’s Common Shares may sell his or her Common Shares on the NYSE at any time prior to the Mergers.

Each Agreement and Plan of Merger may be terminated and the Mergers abandoned, whether before or after approval by MNP’s or SBI’s stockholders, at any time prior to the Closing Date by resolution of either Fund’s Board, if circumstances should develop that, in the opinion of that Board, make proceeding with the Mergers inadvisable with respect to MMU, MNP and SBI, respectively.

Each Agreement and Plan of Merger provides that either Fund may waive compliance with any of the terms or conditions made therein for the benefit of that Fund, other than the requirements that: (a) each Agreement and Plan of Merger be approved by stockholders of MMU and MNP or SBI, as applicable, and (b) MNP or SBI, as applicable, and MMU receive the opinion of Simpson Thacher & Bartlett LLP that the transactions contemplated by each Agreement and Plan of Merger will constitute a tax-free reorganization for federal income tax purposes, if, in the judgment of the Fund’s Board, after consultation with Fund counsel, such waiver will not have a material adverse effect on the benefits intended to be provided by the Mergers to the stockholders of the Fund.

Under each Agreement and Plan of Merger, each Fund, out of its assets and property, will indemnify and hold harmless the other Fund and the members of the Board and officers of the other Fund from and against any and all losses, claims, damages, liabilities or expenses (including, without limitation, the payment of reasonable legal fees and reasonable costs of investigation) to which the other Fund and those board members and officers may become subject, insofar as such loss, claim, damage, liability or expense (or actions with respect thereto) arises out of or is based on (a) any breach by the Fund of any of its representations, warranties, covenants or agreements set forth in this Agreement or (b) any act, error, omission, neglect, misstatement, materially misleading statement, breach of duty or other act wrongfully done or attempted to be committed by the Fund or the members of the Board or officers of the Fund prior to the Closing Date, provided that such indemnification by the Fund is not (i) in violation of any applicable law or (ii) otherwise prohibited as a result of any applicable order or decree issued by any governing regulatory authority or court of competent jurisdiction. In no event will a Fund or the members of the Board or officers of a Fund be indemnified for any losses, claims, damages, liabilities or expenses arising out of or based on conduct constituting willful misfeasance, bad faith, gross negligence or the reckless disregard of duties.

The Board of each Fund, including the Independent Directors, has determined, with respect to its Fund, that the interests of the holders of that Fund’s Common Shares will not be diluted as a result of the Mergers and that participation in the Mergers is in the best interests of that Fund. LMPFA, or an affiliate thereof, will bear the costs of the Mergers, whether or not the Mergers are consummated. Such expenses shall also include, but not be limited to, all costs related to the preparation and distribution of this Proxy Statement/Prospectus, proxy solicitation expenses, SEC registration fees and NYSE listing fees.

Approval of each Agreement and Plan of Merger requires (i) the affirmative vote of a majority of the votes entitled to be cast by MNP Common Shares and MNP Preferred Shares (voting together), (ii) the affirmative vote of a majority of the votes entitled to be cast by SBI Common Shares and SBI Preferred Shares (voting together) and (iii) the affirmative vote of a majority of the votes entitled to be cast by MMU Common Shares and MMU Preferred Shares (voting together), See “Voting Information” below.

Reasons for the Mergers and Board Considerations

Board Considerations

The Funds may be deemed affiliated investment companies as a result of LMPFA and Western Asset serving as each Fund’s investment adviser and subadviser, respectively. In connection with a merger of affiliated

35

Table of Contents

investment companies, Rule 17a-8 requires the board of each affiliated investment company, including a majority of the directors who are not interested persons of the investment company, to determine that (1) participation in the transaction is in the best interests of the investment company, and (2) the interests of the existing stockholders of the investment company will not be diluted as a result of the transaction.

Moreover, Rule 17a-8 requires that the directors request and evaluate such information as may reasonably be necessary to make their findings. Rule 17a-8 does not specify the factors to be considered in making the findings required by the rule. In making its finding that the interests of the Fund’s existing stockholders will not be diluted as a result of the Merger, the Board of each Fund considered that the Mergers would be conducted on the basis of the Funds’ relative net asset values. The SEC has recommended that boards consider the following factors in determining whether a transaction is in the best interests of the investment company, in addition to any others that may be appropriate under the circumstances:

Proposals for the Mergers were presented to the Board of each Fund for consideration at simultaneous in-person meetings held on February 8 and 9, 2023 (together, the “Meeting”), and were approved by each Board at that meeting. At the meeting, LMPFA expressed its belief that the Mergers would be in the best interests of each Fund and provided information and analyses (the “Merger Evaluation Information”) sufficient in LMPFA’s belief for each Board to evaluate the Mergers. In considering the Mergers, with the advice of indpendent counsel to the Independent Directors, the Boards considered the factors noted above in view of LMPFA’s belief that the Mergers would be in the best interests of each Fund, the Merger Evaluation Information and additional information received on an on-going basis in connection with the oversight of each Fund. The discussion below reflects all of the discussions and reviews at the Meeting. The Boards considered LMPFA’s recommendation of the Merger and its belief that the Merger would be in the best interest of each Fund. With respect to each of the above Factors, the Boards considered:

Merger of MNP with and into MMU

Factor 1

Factor 2

36

Table of Contents

Factor 3

Factor 4

Merger of SBI with and into MMU

Factor 1

Factor 2

37

Table of Contents

Factor 3

Factor 4

In view of the forgoing and other relevant factors, the Board of each Fund determined, under the circumstances, that the Mergers (1) would be in the best interests of the shareholders of such Fund and (2) the Mergers would not result in the dilution of the interests of such Fund or its shareholders. The principal factor considered by the Board of each Fund in determining that the Mergers would not result in a dilution of the interests of such Fund or its shareholders was that the Mergers would be effected on the basis of the relative net asset values of the Fund. Otherwise, no single factor was identified by the Board as the principal factor in making the findings required by Rule 17a-8. The Independent Directors of each Board were represented throughout their evaluation of the Mergers by independent counsel. Prior to Meetings, each Board received a memorandum from LMPFA discussing its responsibilities in connection with the Mergers as part of the Merger Evaluation Information and, prior to the Approval Meeting, the Independent Directors of each Board met separately and discussed the Mergers with independent legal counsel in a private session at which no representatives of LMPFA or Western Asset were present.

38

Table of Contents

Federal Income Tax Consequences

The following is a summary of the material federal income tax consequences of the Mergers applicable to a holder of Target Fund Common Shares that receives MMU Common Shares in a Merger or to a holder of MNP Series 1 VRDPS or SBI Series 1 VRDPS that receives MMU Series 1 VRDPS in a Merger. This discussion is based upon the Code, Treasury regulations, judicial authorities, published positions of the Internal Revenue Service (the “IRS”) and other applicable authorities, all as currently in effect and all of which are subject to change or differing interpretations (possibly with retroactive effect). This discussion is limited to U.S. holders (as defined below) that hold their Target Fund Common Shares, MNP Series 1 VRDPS or SBI Series 1 VRDPS as capital assets for federal income tax purposes (generally, assets held for investment). This discussion does not address all of the tax consequences that may be relevant to a particular Target Fund stockholder or to Target Fund stockholders that are subject to special treatment under federal income tax laws.

This discussion does not address the tax consequences of the Mergers under state, local or foreign tax laws. No assurance can be given that the IRS would not assert, or that a court would not sustain, a position contrary to any of the tax consequences set forth below.

Holders of Target Fund Common Shares, MNP Series 1 VRDPS or SBI Series 1 VRDPS are urged to consult with their own tax advisors as to the tax consequences of the Mergers in their particular circumstances, including the applicability and effect of the alternative minimum tax and any state, local or foreign and other tax laws and of changes in those laws.

For purposes of this section, the term “U.S. holder” means a beneficial owner of Target Fund Common Shares, MNP Series 1 VRDPS or SBI Series 1 VRDPS, as applicable, that for federal income tax purposes is:

Tax Consequences of the Mergers Generally

The Funds intend each Merger to qualify as a tax-free reorganization within the meaning of Section 368(a) of the Code. Each Merger is conditioned upon the receipt by both the applicable Target Fund and MMU of an opinion from Simpson Thacher & Bartlett LLP to the effect that, based upon certain facts, assumptions and representations of the parties, the Merger will qualify as a tax-free reorganization within the meaning of Section 368(a) of the Code. Assuming the Merger qualifies for such treatment, the following will be the resulting tax consequences:

(i) the applicable Target Fund and MMU will each be a “party to a reorganization” within the meaning of Section 368(b) of the Code;

(ii) except for consequences regularly attributable to a termination of the applicable Target Fund’s taxable year, no gain or loss will be recognized by the Target Fund as a result of the Mergers or upon the conversion of (a) Target Fund Common Shares into MMU Common Shares, (b) MNP Series 1 VRDPS into MMU Series 1 VRDPS and (c) SBI Series 1 VRDPS into MMU Series 1 VRDPS;

(iii) no gain or loss will be recognized by MMU as a result of the Mergers or upon the conversion of (a) Target Fund Common Shares into MMU Common Shares, (b) MNP Series 1 VRDPS into MMU Series 1 VRDPS and (c) SBI Series 1 VRDPS into MMU Series 1 VRDPS;

39

Table of Contents

(iv) no gain or loss will be recognized by the holders of Target Fund Common Shares upon the conversion of their Target Fund Common Shares into MMU Common Shares, except to the extent such holders are paid cash in lieu of fractional MMU Common Shares in the Merger;

(v) no gain or loss will be recognized by the holders of MNP Series 1 VRDPS upon the conversion of their MNP Series 1 VRDPS into MMU Series 1 VRDPS;

(vi) no gain or loss will be recognized by the holders of SBI Series 1 VRDPS upon the conversion of their SBI Series 1 VRDPS into MMU Series 1 VRDPS;

(vii) the tax basis of the applicable Target Fund’s assets in the hands of MMU will be the same as the tax basis of such assets in the hands of the Target Fund immediately prior to the consummation of the Merger;

(viii) immediately after the Mergers, (a) the aggregate tax basis of the MMU Common Shares received by each holder of Target Fund Common Shares in the Mergers (including that of fractional share interests purchased by MMU) will be equal to the aggregate tax basis of the Target Fund Common Shares owned by such holder immediately prior to the Merger, (b) the aggregate tax basis of the MMU Series 1 VRDPS received by each holder of MNP Series 1 VRDPS in the Mergers will be equal to the aggregate tax basis of the MNP Series 1 VRDPS owned by such holder immediately prior to the Mergers and (c) the aggregate tax basis of the MMU Series 1 VRDPS received by each holder of SBI Series 1 VRDPS in the Mergers will be equal to the aggregate tax basis of the SBI Series 1 VRDPS owned by such holder immediately prior to the Mergers;

(ix) a stockholder’s holding period for MMU Common Shares received pursuant to the Merger (including that of fractional share interests purchased by MMU) will be determined by including the period for which such stockholder held Target Fund Common Shares converted pursuant to the Merger, provided that such Target Fund Common Shares were held by such stockholder as capital assets;

(x) a stockholder’s holding period for MMU Series 1 VRDPS received pursuant to the Merger will be determined by including the period for which such stockholder held MNP Series 1 VRDPS converted pursuant to the Merger, provided that such MNP Series 1 VRDPS were held by such stockholder as capital assets;

(xi) a stockholder’s holding period for MMU Series 1 VRDPS received pursuant to the Merger will be determined by including the period for which such stockholder held SBI Series 1 VRDPS converted pursuant to the Merger, provided that such SBI Series 1 VRDPS were held by such stockholder as capital assets;

(xii) MMU’s holding period with respect to the applicable Target Fund assets transferred pursuant to the Mergers will include the period for which such assets were held by the Target Fund; and

(xiii) the payment of cash to the holders of Target Fund Common Shares in lieu of fractional MMU Common Shares will be treated as though such fractional shares were distributed as part of the Mergers and then redeemed by MMU with the result that the holder of Target Fund Common Shares will generally have a capital gain or loss to the extent the cash distribution differs from such stockholder’s basis allocable to the fractional MMU Common Shares (assuming such Target Fund Common Shares were held by such stockholder as capital assets).

Information Reporting and Backup Withholding

Cash payments received in lieu of fractional MMU Common Shares by a U.S. holder will generally be subject to information reporting unless the holder establishes that it is an exempt recipient. In addition, backup withholding at a rate of 24% may apply to the cash payable to a U.S. holder, unless the holder furnishes its taxpayer identification number (in the case of individuals, their social security number) and otherwise complies with applicable requirements of the backup withholding rules, or the holder otherwise establishes an exemption.

40

Table of Contents

Any amounts withheld from payments to a holder under the backup withholding rules are not additional tax and will be allowed as a refund or credit against the holder’s federal income tax liability, provided the required information is timely furnished to the IRS.

Reporting Requirements

A holder of Target Fund Common Shares, MNP Series 1 VRDPS or SBI Series 1 VRDPS who receives MMU Common Shares or MMU Series 1 VRDPS, as applicable, as a result of a Merger will generally be required to retain records pertaining to the Merger. Each holder of Target Fund Common Shares, MNP Series 1 VRDPS or SBI Series 1 VRDPS who is required to file a U.S. tax return and who is a “significant holder” that receives MMU Common Shares or MMU Series 1 VRDPS in a Merger will be required to file a statement with the holder’s federal income tax return setting forth certain information, including such holder’s basis in and the fair market value of such holder’s Target Fund Common Shares, MNP Series 1 VRDPS or SBI Series 1 VRDPS surrendered in the Merger. Holders of Target Fund Common Shares, MNP Series 1 VRDPS or SBI Series 1 VRDPS should consult with their own tax advisors regarding the application of these reporting requirements.

Other Tax Considerations

While neither MMU nor either Target Fund is aware of any adverse state or local tax consequences of the Mergers, they have not requested any ruling or opinion with respect to such consequences, and stockholders should consult their own tax advisor with respect to such matters.

Each Target Fund shall, to the extent necessary, declare a dividend or dividends, with a record and ex-dividend date prior to the business day immediately before the Closing Date, which, together with all previous dividends, shall have the effect of distributing to the shareholders of the Target Fund substantially all of the Target Fund’s investment company taxable income (as defined in Section 852(b) of the Code, but computed without regard to any deduction for dividends paid) and net capital gains (after reduction for any capital loss carryover) for all taxable periods ending on or before the Closing Date. Such dividends will be included in the taxable income of the stockholders of the Target Fund.

Information Regarding Net Operating Loss and Capital Loss Carryovers

As of December 31, 2022, the Funds are entitled to capital loss carryovers for federal income tax purposes in the amounts set forth below:

MNP

Based on the recent data referred to above, the Merger would impact the use of MNP’s capital loss carryovers in the following manner: (1) MNP’s carryovers would benefit the stockholders of the combined Fund, rather than only the stockholders of MNP; and (2) the aggregate amount of the carryovers that could be utilized in any taxable year would be limited to the product of the long-term tax-exempt rate at the time of the Merger and the net asset value of MNP at that time.

SBI

Based on the recent data referred to above, the Merger would impact the use of SBI’s capital loss carryovers in the following manner: (1) SBI’s carryovers would benefit the stockholders of the combined Fund, rather than

41

Table of Contents

only the stockholders of SBI; and (2) the aggregate amount of the carryovers that could be utilized in any taxable year would be limited to the product of the long-term tax-exempt rate at the time of the Merger and the net asset value of SBI at that time.

MMU

Based on the recent data referred to above, the Mergers would impact the use of MMU’s capital loss carryovers in the following manner: (1) MMU’s capital loss carryovers would benefit the stockholders of the combined Fund, rather than only the stockholders of MMU; and (2) address possible Section 384 consequences.

Information Applicable to Both Funds

The capital loss carryovers and limitations described above may change significantly between now and the Closing Date. Further, the ability of each Fund to use loss carryovers (even in the absence of the Mergers) depends on factors other than loss limitations, such as the future realization of capital gains or losses.

Board Recommendation and Required Vote

Because the Merger of MNP into MMU has been approved by at least 75% of MNP’s “Continuing Directors,” as that term is defined in MNP’s charter, approval of the Merger requires the affirmative vote of a majority of votes entitled to be cast by holders of MNP Common Shares and holders of MNP Preferred Shares (voting as a class). Additionally, because the Merger of SBI into MMU has been approved by at least 70% of SBI’s Board, approval of the Merger requires the affirmative vote of a majority of votes entitled to be cast by holders of SBI Common Shares and holders of preferred stock of SBI Preferred Shares (voting as a class). Similarly, because the Merger has been approved by at least 75% of MMU’s “Continuing Directors” (as that term is defined in MMU’s charter) approval of each Merger requires the affirmative vote of a majority of votes entitled to be cast by holders of MMU Common Shares and holders of MMU Preferred Shares (voting as a class). Approval of the Proposal will occur only if a sufficient number of votes at the Meeting are cast “FOR” the Proposal. Abstentions effectively result in a vote AGAINST the Proposal. Any broker non-votes would effectively be treated as a vote “AGAINST” the Proposal.

Each Fund’s Board of Directors, including the Independent Directors, unanimously recommends that stockholders of each Fund vote FOR the approval of the merger of the applicable Target Fund with and into MMU in accordance with the Maryland General Corporation Law.

42

Table of Contents

PORTFOLIO SECURITIES

The securities in which each Target Fund may invest are permissible for investment under MMU’s investment objectives and strategies. Based on current market conditions which may change, LMPFA estimates that the Funds will not experience any significant portfolio turnover in connection with either Merger.

No securities of MMU need to be sold in order for MMU to comply with its investment restrictions or policies. The Funds may buy and sell securities in the normal course of their operations.

INFORMATION ABOUT MANAGEMENT OF THE FUNDS

Information About Directors and Officers

The overall management of the business and affairs is vested in the Board of Directors of each Fund. In accordance with each Fund’s charter, each Board of Directors is divided into three classes: Class I, Class II and Class III. Each Board approves all significant agreements between such Fund and persons or companies furnishing services to the Fund. The day-to-day operation of the Fund is delegated to the officers of each Fund, LMPFA and Western Asset, subject always to the investment objectives, restrictions and policies of each Fund and to the general supervision of the Board. The following table provides information concerning the Directors of each Fund.

43

Table of Contents

44

Table of Contents

45

Table of Contents

46

Table of Contents

The Directors were selected to join each Board based upon the following as to each Director: his or her character and integrity; such person’s service as a board member of other funds in the Franklin Templeton fund complex; such person’s willingness to serve and willingness and ability to commit the time necessary to perform the duties of a Director; as to each Director other than Ms. Trust, his or her status as not being an “interested person” as defined in the 1940 Act; and, as to Ms. Trust, her role with Franklin Templeton. No factor, by itself, was controlling.

In addition to the information provided in the table included above, each Director possesses the following attributes: Mr. Agdern, experience in business and as a legal professional; Ms. Colman, experience as a consultant and investment professional; Mr. Cronin, legal and managerial experience; Mr. Cucchi, experience as a college professor and leadership experience as an academic dean; Ms. Kamerick, experience in business and finance, including financial reporting, and experience as a board member of a highly regulated financial services company; Ms. Kumar, financial and accounting experience as the chief financial officer of other companies and experience as a board member of private equity funds; and Ms. Trust, investment management and risk oversight experience as an executive and portfolio manager and leadership roles within Franklin Templeton and affiliated entities. References to the qualifications, attributes and skills of the Directors are pursuant to requirements of the Securities and Exchange Commission, do not constitute holding out of the Board or any Director 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.

47

Table of Contents

Security Ownership of Management

The following table provides information concerning the dollar range of equity securities owned beneficially by each Director and nominee for election as Director as of December 31, 2022:

At March 1, 2023, the Directors and officers of the Funds as a group beneficially owned less than 1% of the outstanding shares of each Fund’s common stock.

No Director or nominee for election as Director who is not an “interested person” of the Funds as defined in the 1940 Act, nor any immediate family members, to the best of the Funds’ knowledge, had any interest in the Funds’ investment adviser, or any person or entity (other than the Funds) directly or indirectly controlling, controlled by, or under common control with Franklin Templeton as of December 31, 2022.

Director Compensation

Under the federal securities laws, and in connection with the Meeting, the Funds are required to provide to stockholders in connection with the Meeting information regarding compensation paid to the Directors by the Funds, as well as by the various other investment companies advised by LMPFA. The following table provides information concerning the compensation paid to each Director by the Funds and the Fund Complex during the calendar year ended December 31, 2022 and the total compensation paid to each Director during the fiscal years ended November 30, 2022 for each Target Fund and May 31, 2022 for MMU. Certain of the Directors listed below are members of the Funds’ Sub-Audit Committees, as well as chairpersons of the Audit, Nominating, Pricing and Valuation and Compensation Committees of the Boards of each Fund. Accordingly, the amounts provided in the table include compensation for service on all such committees. The Funds do not provide any

48

Table of Contents

pension or retirement benefits to Directors. In addition, no remuneration was paid during the fiscal year ended November 30, 2022 to Ms. Trust who is an “interested person” as defined in the 1940 Act.

As of January 1, 2023, the Funds paid each of the Independent Directors an annual fee of $160,000, plus (a) a fee of $25,000 for attendance at each regular meeting of the Board of Trustees and (b) a fee of $2,000 for each telephonic meeting of the Board of Trustees. In addition to the payments described above, the Lead Independent Trustee of the Board of Trustees receives $55,000, the chairperson of the Audit Committee receives $35,000, each member of the Audit Sub-Committee receives $35,000, the chairperson of the Nominating Committee receives $15,000, the chairperson of the Pricing and Valuation Committee receives $20,000, the chairperson of the Compensation Committee receives $20,000 and the Compliance Liaison receives $15,000. The annual compensation, fees and expenses are allocated among all the funds in the fund complex, including the Fund, on the basis of average net assets.

Responsibilities of the Board of MNP, SBI and MMU

The Board of Directors is responsible under applicable state law for overseeing generally the management and operations of each Fund. The Directors oversee each Fund’s operations by, among other things, meeting at its regularly scheduled meetings and as otherwise needed with each Fund’s management and evaluating the performance of each Fund’s service providers including LMPFA, Western Asset, the custodian and the transfer agent. As part of this process, the Directors consult with each Fund’s independent auditors and with their own separate independent legal counsel.

The Directors review each Fund’s financial statements, performance, net asset value and market price and the relationship between them, as well as the quality of the services being provided to each Fund. As part of this process, the Directors review the Fund’s fees and expenses in light of the nature, quality and scope of the services being received while also seeking to ensure that each Fund continues to have access to high quality services in the future.

The Board of Directors has four regularly scheduled meetings each year, and additional meetings may be scheduled as needed. In addition, the Board has a standing Audit Committee, Nominating Committee,

49

Table of Contents

Compensation Committee and Pricing and Valuation Committee that meet periodically and whose responsibilities are described below.

With respect to MNP, during the fiscal year ended November 30, 2022, the Board of Directors held four regular meetings and two special meetings. Each Director attended at least 75% of the aggregate number of meetings of the Board and the committees for which he or she was eligible. With respect to SBI during the fiscal year ended November 30, 2022, the Board of Directors held four regular meetings and two special meetings. Each Director attended at least 75% of the aggregate number of meetings of the Board and the committees for which he or she was eligible With respect to MMU, during the fiscal year ended May 31, 2022, the Board of Directors held four regular meetings and three special meetings. Each Director attended at least 75% of the aggregate number of meetings of the Board and the committees for which he or she was eligible. The Funds do not have a formal policy regarding attendance by Directors at annual meetings of stockholders.

Each of the Audit Committee, the Nominating Committee, the Compensation Committee and the Pricing and Valuation Committee is composed of all Directors who have been determined not to be “interested persons” of each Fund, LMPFA, Western Asset or their affiliates within the meaning of the 1940 Act, and who are “independent” as defined in the New York Stock Exchange listing standards (“Independent Directors”), and is chaired by an Independent Director. The Board in its discretion from time to time may establish ad hoc committees.

The Board of Directors is currently composed of seven directors, six of whom are Independent Directors. Jane E. Trust serves as Chairman of the Board. Ms. Trust is an “interested person” of each Fund. The appointment of Ms. Trust as Chairman reflects the Board’s belief that her experience, familiarity with each Fund’s day-to-day operations and access to individuals with responsibility for each Fund’s management and operations provides the Board with insight into each Fund’s business and activities and, with her access to appropriate administrative support, facilitates the efficient development of meeting agendas that address each Fund’s business, legal and other needs and the orderly conduct of board meetings. Ms. Kamerick serves as Lead Independent Director. The Chairman develops agendas for Board meetings in consultation with the Lead Independent Director and presides at all meetings of the Board. The Lead Independent Director, among other things, chairs executive sessions of the Independent Directors, serves as a spokesperson for the Independent Directors and serves as a liaison between the Independent Directors and each Fund’s management between Board meetings. The Independent Directors regularly meet outside the presence of management and are advised by independent legal counsel. The Board also has determined that its leadership structure, as described above, is appropriate in light of the size and complexity of each Fund, the number of Independent Directors (who constitute a super-majority of the Board’s membership) and the Board’s general oversight responsibility. The Board also believes that its leadership structure not only facilitates the orderly and efficient flow of information to the Independent Directors from management, including Western Asset, each Fund’s subadviser, but also enhances the independent and orderly exercise of its responsibilities.

Audit Committee

Each Fund’s Audit Committee is composed entirely of all of the Independent Directors: Mses. Colman, Kamerick and Kumar and Messrs. Agdern, Cronin and Cucchi. Ms. Kumar serves as the Chair of the Audit Committee and has been determined by the Board to be an “audit committee financial expert.” The principal functions of the Audit Committee are: to (a) oversee the scope of each Fund’s audit, each Fund’s accounting and financial reporting policies and practices and its internal controls and enhance the quality and objectivity of the audit function; (b) approve, and recommend to the Independent Board Members (as such term is defined in the Audit Committee Charter) for their ratification, the selection, appointment, retention or termination of each Fund’s independent registered public accounting firm, as well as approving the compensation thereof; and (c) approve all audit and permissible non-audit services provided to each Fund and certain other persons by each Fund’s independent registered public accounting firm. Each Target Fund’s Audit Committee met five times during the fiscal year ended November 30, 2022 and MMU’s Audit Committee met five times during the fiscal

50

Table of Contents

year ended May 31, 2022. Each Fund’s Audit Committee operates under a written charter adopted and approved by the Board, a copy of which is available on the Fund’s website at www.franklintempleton.com/investments/options/closed-end-funds and click on the name of the Fund.

Nominating Committee

Each Fund’s Nominating Committee, the principal function of which is to select and nominate candidates for election as Directors of each Fund, is composed of all of the Independent Directors: Mses. Colman, Kamerick and Kumar and Messrs. Agdern, Cronin and Cucchi. Mr. Cronin serves as the Chair of the Nominating Committee. The Nominating Committee may consider nominees recommended by the stockholder as it deems appropriate. Stockholders who wish to recommend a nominee should send recommendations to the Fund’s Secretary that include all information relating to such person that is required to be disclosed in solicitations of proxies for the election of Directors. A recommendation must be accompanied by a written consent of the individual to stand for election if nominated by the Board of Directors and to serve if elected by the stockholders. Each Target Fund’s Nominating Committee met four times during the fiscal year ended November 30, 2022 and MMU’s Nominating Committee met four times during the fiscal year end May 31, 2022. Each Fund’s Nominating Committee operates under a written charter adopted and approved by the Board, a copy of which is available on the Fund’s website at www.franklintempleton.com/investments/options/closed-end-funds and click on the name of the Fund.

The Nominating Committee identifies potential nominees through its network of contacts, and in its discretion may also engage a professional search firm. The Nominating Committee meets to discuss and consider such candidates’ qualifications and then chooses a candidate by majority vote. The Nominating Committee does not have specific, minimum qualifications for nominees and has not established specific qualities or skills that it regards as necessary for one or more of each Fund’s Directors to possess (other than any qualities or skills that may be required by applicable law, regulation or listing standard). However, as set forth in the Nominating Committee Charter, in evaluating a person as a potential nominee to serve as a Director of the Fund, the Nominee Committee may consider the following factors, among any others it may deem relevant:

Further, each Fund has adopted Director qualification requirements which can be found in each Fund’s bylaws and are applicable to all Directors that may be nominated or elected to serve as Directors, unless a majority of the Board of Directors then in office determine by resolution that failure to satisfy a particular

51

Table of Contents

qualification requirement will not present undue conflicts or impede the ability of the individual to discharge the duties of a Director or the free flow of information among Directors or between LMPFA and the Board of Directors. The qualification requirements include: (i) experience requirements; (ii) limits on service on other boards; and (iii) character and fitness requirements. The Nominating Committee, in its sole discretion, determines whether an individual satisfies these qualifications.

The Nominating Committee does not have a formal diversity policy with regard to the consideration of diversity in identifying potential director nominees but may consider diversity of professional experience, education and skills when evaluating potential nominees for Board membership.

Pricing and Valuation Committee

Each Fund’s Pricing and Valuation Committee is composed of all of the Independent Directors. The members of the Pricing and Valuation Committee are Colman, Kamerick and Kumar and Messrs. Agdern, Cronin and Cucchi. Ms. Colman chi serves as Chair of each Fund’s Pricing and Valuation Committee. The principal function of the Pricing and Valuation Committee is to assist the Board with its oversight of the process for valuing portfolio securities in light of applicable law, regulatory guidance and applicable policies and procedures adopted by each Fund. Each Target Fund’s Pricing and Valuation Committee met four times during the fiscal year ended November 30, 2022 and MMU’s Pricing and Valuation Committee met four times during the fiscal year ended May 31, 2022.

Compensation Committee

Each Fund’s Compensation Committee is composed of all of the Independent Directors. The members of the Compensation Committee Mses. Colman, Kamerick and Kumar and Messrs. Agdern, Cronin and Cucchi. Mr. Cucchi serves as Chair of each Fund’s Compensation Committee. The principal function of the Compensation Committee is to recommend the appropriate compensation of the Independent Directors for their service on the Board and the committees of the Board. Each Target Fund’s Compensation Committee met once during the fiscal year ended November 30, 2022 and MMU’s Compensation Committee met once during the fiscal year ended May 31, 2022. The Compensation Committee operates under a written charter adopted and approved by the Board, a copy of which is available on the Fund’s website at www.franklintempleton.com/investments/options/closed-end-funds and click on the name of the Fund.

Officers

Each Fund’s executive officers are chosen each year at a regular meeting of the Board of Directors of the Fund, to hold office until their respective successors are duly elected and qualified. The same individuals serve as officers of each Fund. In addition to Ms. Trust, each Fund’s Chairman, CEO and President, the executive officers of the Funds currently are:

52

Table of Contents

53

Table of Contents

54

Table of Contents

Section 16(a) Beneficial Ownership Reporting Compliance

Section 16(a) of the 1934 Act and Section 30(h) of the 1940 Act in combination require each Fund’s Directors and principal officers, persons who own more than 10% of the Funds’ common stock, LMPFA and certain of its affiliates, to file reports of ownership and changes in ownership with the SEC and the NYSE. Such persons and entities are required by SEC regulations to furnish each of the Funds with copies of all such filings. Based solely on its review of the copies of such forms received by it, or written representations from certain reporting persons, MNP believes that, during the fiscal year ended November 30, 2022, all such filing requirements were met with respect to MNP. Based solely on its review of the copies of such forms received by it, or written representations from certain reporting persons, SBI believes that, during the fiscal year ended November 30, 2022, all such filing requirements were met with respect to SBI. In addition, with respect to MMU and based solely on its review of the copies of such forms received by it, or written representations from certain reporting persons, MMU believes that, during the fiscal year ended May  31, 2022, all such filing requirements were met with respect to MMU.

Investment Manager and Sub-Adviser

LMPFA serves as each Fund’s investment manager. LMPFA, located at 280 Park Avenue, New York, NY 10017, is a registered investment adviser that provides administrative and compliance oversight services to each Fund.

Under each Fund’s management agreement with LMPFA (the “Management Agreements”), subject to the supervision and direction of each Fund’s Board, LMPFA is delegated the responsibility of managing the Fund’s portfolio in accordance with the Fund’s stated investment objective and policies, making investment decisions for the Fund and placing orders to purchase and sell securities. LMPFA performs administrative and management services necessary for the operation of each Fund, such as (i) supervising the overall administration of the Fund, including negotiation of contracts and fees with and the monitoring of performance and billings of the Fund’s transfer agent, stockholder servicing agents, custodian and other independent contractors or agents; (ii) providing certain compliance, Fund accounting, regulatory reporting, and tax reporting services; (iii) preparing or participating in the preparation of Board materials, registration statements, proxy statements and reports and other communications to stockholders; (iv) maintaining the Fund’s existence, and (v) maintaining the registration and qualification of the Fund’s shares under federal and state laws.

Each Fund’s Management Agreement will continue in effect from year to year provided such continuance is specifically approved at least annually (a) by the Fund’s Board or by a majority of the outstanding voting securities of the Fund (as defined in the 1940 Act), and (b) in either event, by a majority of the Independent Directors with such Independent Directors casting votes in person at a meeting called for such purpose. Each Fund’s Management Agreement provides that LMPFA may render services to others. Each Fund’s Management Agreement is terminable without penalty on not more than 60 days’ nor less than 30 days’ written notice by the Fund when authorized either by a vote of holders of shares representing a majority of the voting power of the outstanding voting securities of the Fund (as defined in the 1940 Act) or by a vote of a majority of the Fund’s Directors, or by LMPFA on not less than 90 days’ written notice, and will automatically terminate in the event of its assignment. Each Fund’s Management Agreement provides that neither LMPFA nor its personnel shall be liable for any error of judgment or mistake of law or for any loss arising out of any investment or for any act or omission in the execution of security transactions for the Fund, except for willful misfeasance, bad faith or gross negligence or reckless disregard of its or their obligations and duties.

LMPFA does not provide day-to-day portfolio management services. Rather, portfolio management for each Fund is provided by Western Asset Management Company, LLC (“Western Asset”), located at 385 East Colorado Boulevard, Pasadena, California 91101 and 620 Eighth Avenue, New York, New York 10018.

55

Table of Contents

Western Asset provides services to each Fund pursuant to a sub-advisory agreement between LMPFA and Western Asset (the “Western Asset Sub-Advisory Agreements”). Under each Western Asset Sub-Advisory Agreement, subject to the supervision and direction of each Fund’s Board and LMPFA, Western Asset will manage the Fund’s portfolio in accordance with the Fund’s stated investment objective and policies, assist in supervising all aspects of the Fund’s operations, make investment decisions for the Fund, place orders to purchase and sell securities, and employ professional portfolio managers and securities analysts who provide research services to the Fund.

The Western Asset Sub-Advisory Agreements will continue in effect from year to year provided such continuance is specifically approved at least annually (a) by the Board or by a majority of the outstanding voting securities of the Fund (as defined in the 1940 Act), and (b) in either event, by a majority of the Independent Directors with such Independent Directors casting votes in person at a meeting called for such purpose. The Board or a majority of the outstanding voting securities of each Fund (as defined in the 1940 Act) may terminate that Western Asset Sub-Advisory Agreement without penalty, in each case on not more than 60 days’ nor less than 30 days’ written notice to Western Asset. Western Asset may terminate each Western Asset Sub-Advisory Agreement on 90 days’ written notice to each Fund and LMPFA. LMPFA and Western Asset may terminate each Western Asser Sub-Advisory Agreement upon their mutual written consent. Each Western Asset Sub-Advisory Agreement will terminate automatically in the event of assignment by Western Asset and shall not be assignable by LMPFA without the consent of Western Asset.

MNP currently pays LMPFA an investment management fee, calculated daily and paid monthly, at an annual rate of 0.55% of MMU’s average weekly net managed assets. SBI and MMU currently pay LMPFA an investment management fee, calculated daily and paid monthly, at an annual rate of 0.55% of their respective average daily net assets. The total dollar amounts paid to LMPFA under the Management Agreements with each Fund for the last three fiscal years are as follows:

With respect to each Fund, LMPFA pays sub-advisory fees to Western Asset at the rate of 70% of the management fee paid to LMPFA.

LMPFA and Western Asset are wholly-owned subsidiaries of Franklin Resources, Inc.. Franklin Resources, whose principal executive offices are at One Franklin Parkway, San Mateo, CA, 94403, is a global asset management organization with subsidiaries operating as Franklin Templeton and serving clients in over 155 countries.

Additional information about the factors considered by the Board of MMU in approving its Management Agreement and Sub-Advisory Agreements is set forth in MMU’s Semi-Annual Report to Stockholders for the Semi-Annual Period ending November 30, 2022. Additional information about the factors considered by the Board of each Target Fund in approving its Management Agreement and Sub-Advisory Agreements is set forth in each Target Fund’s Annual Report to Stockholders for the Fiscal Year ended November 30, 2022.

Codes of Ethics

Pursuant to Rule 17j-1 under the 1940 Act, each of the Funds, LMPFA and Western Asset have adopted codes of ethics that permit their respective personnel to invest in securities for their own accounts, including securities that may be purchased or held by the Funds (the “Codes of Ethics”). All personnel must place the interests of clients first and avoid activities, interests and relationships that might interfere with the duty to make

56

Table of Contents

decisions in the best interests of the clients. All personal securities transactions by employees must adhere to the requirements of the applicable Codes of Ethics and must be conducted in such a manner as to avoid any actual or potential conflict of interest, the appearance of such a conflict, or the abuse of an employee’s position of trust and responsibility.

When personnel covered by either Fund’s Code of Ethics are employed by more than one of the managers affiliated with Legg Mason, those employees may be subject to such affiliate’s Code of Ethics adopted pursuant to Rule 17j-1, rather than the Codes of Ethics of the Funds.

The Codes of Ethics of the Funds, LMPFA, and Western Asset can be reviewed and copied at the SEC’s Public Reference Room in Washington, DC, that information on the operation of the Public Reference Room may be obtained by calling the SEC at 1-202-551-8090, that these codes of ethics are available on the EDGAR Database on the SEC’s Internet site at http://www.sec.gov, and that copies of these codes of ethics 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.

Proxy Voting Policies

Although individual Directors may not agree with particular policies or votes by LMPFA or Western Asset each Fund’s Board has delegated proxy voting discretion to LMPFA and/or Western Asset, believing that LMPFA and/or Western Asset should be responsible for voting because it is a matter relating to the investment decision making process.

LMPFA delegates the responsibility for voting proxies for each Fund to Western Asset through its contracts with Western Asset. Western Asset will use its own proxy voting policies and procedures to vote proxies. Accordingly, LMPFA does not expect to have proxy-voting responsibility for the Funds. Should LMPFA become responsible for voting proxies for any reason, such as the inability of Western Asset to provide investment advisory services, LMPFA shall utilize the proxy voting guidelines established by the most recent subadviser to vote proxies until a new subadviser is retained. In the case of a material conflict between the interests of LMPFA (or its affiliates if such conflict is known to persons responsible for voting at LMPFA) and either Fund, the Board of Directors of LMPFA shall consider how to address the conflict and/or how to vote the proxies. LMPFA shall maintain records of all proxy votes in accordance with applicable securities laws and regulations, to the extent that LMPFA votes proxies. LMPFA shall be responsible for gathering relevant documents and records related to proxy voting from Western Asset and providing them to the relevant Fund as required for the Fund to comply with applicable rules under the 1940 Act.

LMPFA’s and Western Asset’s Proxy Voting Policies and Procedures govern in determining how proxies relating to each Fund’s portfolio securities are voted and are attached as Appendix C and D, respectively, to this Proxy Statement/Prospectus. Information regarding how each Fund voted proxies (if any) relating to portfolio securities during the most recent 12-month period ended June 30 is available without charge (1) by calling 888-777-0102, (2) on the Fund’s website at http://www.lmcef.com and (3) on the SEC’s website at http://www.sec.gov.

57

Table of Contents

Investment Professionals of the Funds

Below is summary information for the Funds’ investment professionals. Certain employees of Western Asset listed below are members of the management teams of each Fund; others are involved in the management of only one of the Funds.

Other Accounts Managed by Investment Professionals

The table below identifies the number of accounts (other than the Funds) for which the each Fund’s investment professionals have day-to-day management responsibilities and the total assets in such accounts, within each of the following categories: registered investment companies, other pooled investment vehicles and other accounts. Data for registered investment companies is based on the specific investment professionals that are named in the applicable disclosure documents. Data for other pooled investment vehicles and other accounts is based on Western Asset’s practice of naming a particular individual to maintain oversight responsibility for each vehicle/account. Where the named individual has been assigned primary responsibility for oversight of another pooled investment vehicle or other account, that vehicle/account has been allocated exclusively to that

58

Table of Contents

individual for disclosure purposes. For each category, the number of accounts and total assets in the accounts where fees are based on performance is also indicated as of November 30, 2022.

Investment Professional Compensation

With respect to the compensation of the investment professionals, Western Asset’s compensation system assigns each employee a total compensation range, which is derived from annual market surveys that benchmark each role with its job function and peer universe. This method is designed to reward employees with total compensation reflective of the external market value of their skills, experience, and ability to produce desired results. Standard compensation includes competitive base salaries, generous employee benefits, and a retirement plan.

In addition, Western Asset’s employees are eligible for bonuses. These are structured to closely align the interests of employees with those of Western Asset, and are determined by the professional’s job function and pre-tax performance as measured by a formal review process. All bonuses are completely discretionary. The principal factor considered is an investment professional’s investment performance versus appropriate peer groups and benchmarks (e.g., a securities index and with respect to a fund, the benchmark set forth in the fund’s Prospectus to which the fund’s average annual total returns are compared or, if none, the benchmark set forth in the fund’s annual report). Performance is reviewed on a 1-, 3- and 5-year basis for compensation—with 3 years having the most emphasis. Western Asset may also measure an investment professional’s pre-tax investment performance against other benchmarks, as it determines appropriate. Because investment professionals are generally responsible for multiple accounts (including the funds) with similar investment strategies, they are generally compensated based on the performance of the aggregate group of similar accounts, rather than a specific account. Other factors that may be considered when making bonus decisions include client service, business development, length of service to Western Asset, management or supervisory responsibilities, contributions to developing business strategy and overall contributions to Western Asset’s business.

59

Table of Contents

Finally, in order to attract and retain top talent, all professionals are eligible for additional incentives in recognition of outstanding performance. These are determined based upon the factors described above and include Legg Mason stock options and long-term incentives that vest over a set period of time past the award date.

Potential Conflicts of Interest

LMPFA, Western Asset and the portfolio managers have interests which may conflict with the interests of the Fund. LMPFA and Western Asset currently and may at some time in the future manage and/or advise other investment funds or accounts with the same or substantially similar investment objectives and strategies as the Fund. As a result, LMPFA, Western Asset and the Funds’ portfolio managers may devote unequal time and attention to the management of each Fund and those other funds and accounts, and may not be able to formulate as complete a strategy or identify equally attractive investment opportunities as might be the case if they were to devote substantially more attention to the management of each Fund. LMPFA, Western Asset and the Funds’ portfolio managers may identify a limited investment opportunity that may be suitable for multiple funds and accounts, and the opportunity may be allocated among these several funds and accounts, which may limit the Funds’ ability to take full advantage of the investment opportunity. Additionally, transaction orders may be aggregated for multiple accounts for purpose of execution, which may cause the price or brokerage costs to be less favorable to each Fund than if similar transactions were not being executed concurrently for other accounts. At times, a portfolio manager may determine that an investment opportunity may be appropriate for only some of the funds and accounts for which he or she exercises investment responsibility, or may decide that certain of the funds and accounts should take differing positions with respect to a particular security. In these cases, the portfolio manager may place separate transactions for one or more funds or accounts which may affect the market price of the security or the execution of the transaction, or both, to the detriment or benefit of one or more other funds and accounts. For example, a portfolio manager may determine that it would be in the interest of another account to sell a security that each Fund holds, potentially resulting in a decrease in the market value of the security held by each Fund.

The portfolio managers may also engage in cross trades between funds and accounts, may select brokers or dealers to execute securities transactions based in part on brokerage and research services provided to LMPFA or Western Asset which may not benefit all funds and accounts equally and may receive different amounts of financial or other benefits for managing different funds and accounts. Finally, LMPFA or its affiliates may provide more services to some types of funds and accounts than others.

There is no guarantee that the policies and procedures adopted by LMPFA, Western Asset and the Funds will be able to identify or mitigate the conflicts of interest that arise between the Fund and any other investment funds or accounts that LMPFA and or Western Asset may manage or advise from time to time.

Investment Professional Securities Ownership

The table below identifies the dollar range of securities beneficially owned by the investment professionals of each Fund as of November 30, 2022.

60

Table of Contents

Dollar Range ownership is as follows:

A: none; B: $1 - $10,000; C: 10,001 - $50,000; D: $50,001 - $100,000; E: $100,001 - $500,000; F: $500,001 - $1 million; G: over $1 million

ADDITIONAL INFORMATION ABOUT THE FUNDS

Further information about MNP is included MNP’s Annual Report to Stockholders for the Fiscal Year Ended November 30, 2022, filed on January 26, 2023 (accession no. 0001193125-23-015796), SBI’s Annual Report to Stockholders for the Fiscal Year Ended November 30, 2022, filed on January 30, 2023 (accession no. 0001193125-23-018467) and MMU’s Semi-Annual Report to Stockholders for the Six-Month Period Ended November 30, 2022, filed on January 27, 2023 (accession no. 0001193125-23-017174), and Annual Report to Stockholders for the Fiscal Year Ended May 31, 2022, filed on August 1, 2022 (accession no. 0001193125-22-208348), which highlight certain important information such as investment performance and expense and financial information, are incorporated by reference into this Proxy Statement/Prospectus. In addition, stockholder reports, proxy materials and other information concerning MNP (File No. 811-07362), SBI (File No. 811-6506) and MMU (File No. 811-06629) can be inspected at the NYSE. You may receive free of charge a copy of the SAI, or the annual report and semi-annual report for a Fund, by contacting MNP, SBI or MMU at 888-777-0102, by writing either Fund at the address listed above or by visiting our website at www.franklintempleton.com/investments/options/closed-end-funds.

The Funds are subject to the informational requirements of the 1934 Act and in accordance therewith, file reports and other information including proxy material, reports and charter documents with the SEC. These reports and other information can be inspected and copied at the public reference facilities maintained by the SEC at 100 F Street, NE, Washington, DC 20549. Reports and other information about each Fund are available on the Edgar Database on the SEC’s website at www.sec.gov. Copies of such material can also be obtained from the Public Reference Branch, Office of Consumer Affairs and Information Services, SEC, 100 F Street, NE, Washington, DC 20549 at prescribed rates. You may obtain information about the operation of the Public Reference Room by calling the SEC at 202-551-8090.

NET ASSET VALUE, MARKET PRICE AND PREMIUM/DISCOUNT

Common shares of closed-end investment companies, such as the Funds, have frequently traded at a discount from net asset value, but in some cases trade at a premium. Shares of closed-end investment companies investing primarily in fixed income securities tend to trade on the basis of income yield relative to the market price of the shares and the market price may also be affected by trading volume, general market and economic conditions and other factors beyond the control of the fund. As a result, the market price of each Fund’s Common Shares may be greater or less than the NAV per share. Since the commencement of each Fund’s operations, each Fund’s Common Shares have traded in the market at prices that were generally below NAV per share.

61

Table of Contents

The following tables set forth the high and low sales prices for MMU Common Shares and Target Fund Common Shares on the NYSE, the NAV per share and the discount or premium to NAV per share represented by the quotation for each quarterly period during the last two calendar years.

MMU (Acquiring Fund) Fiscal Year End is May 31

MNP (Target Fund) Fiscal Year End is November 30