MFS High Yield Municipal Trust (CMU) launches 50% self-tender offer

Rhea-AI Filing Summary

MFS High Yield Municipal Trust commenced a self-tender offer to purchase for cash up to 50% (12,746,391 shares) of its outstanding common shares. The price payable is 99% of net asset value per share as of the Expiration Date plus any unpaid dividends accrued through May 5, 2026. The Offer commenced on April 6, 2026 and the Schedule TO amendment reports this tender offer and attaches the Offer to Purchase and Letter of Transmittal.

Key Figures

Maximum shares to be purchased: 12,746,391 shares Percent of outstanding: 50% Offer price: 99% of NAV per share +2 more

5 metrics

Maximum shares to be purchased 12,746,391 shares Up to 50% of outstanding common shares

Percent of outstanding 50% Maximum portion of common shares subject to the Offer

Offer price 99% of NAV per share Price net to seller as of the Expiration Date

Accrued dividends included through May 5, 2026 Unpaid dividends accrued added to the price per share

Offer commencement date April 6, 2026 Date the Offer commenced

Key Terms

Tender Offer, Schedule TO, Letter of Transmittal, Net Asset Value per share

4 terms

Tender Offer financial

"commencement of a tender offer (the “Offer”) on April 6, 2026"

A tender offer is a proposal made by a person or company to buy shares from existing shareholders at a set price, usually higher than the current market value, within a specific time frame. It matters to investors because it can lead to a change in ownership or control of a company, and shareholders must decide whether to sell their shares at the offered price.

Schedule TO regulatory

"This Tender Offer Statement on Schedule TO is filed by MFS High Yield Municipal Trust"

A phrase indicating that a company plans or intends to hold an event, publish information, or take an action at a specified future time, but that the timing is not guaranteed and may change. For investors it signals an expected milestone—like an earnings call, product launch, or filing—so think of it as a calendar note rather than a firm promise; timing shifts can affect trading, expectations, and planning.

Letter of Transmittal financial

"the related Letter of Transmittal (the “Letter of Transmittal”"

A letter of transmittal is a written form investors use when sending physical stock certificates or electronic ownership documents to a company or its agent to surrender shares, tender them in an offer, or claim payment or replacement securities. It acts like a packing slip that lists what is enclosed, gives instructions on how the transfer should be handled, and provides proof of the transaction—important for ensuring investors receive the correct payment or new securities without delay or dispute.

Net Asset Value per share financial

"amount per share, net to the seller in cash, equal to 99% of the net asset value per share"

Net asset value per share is the total value of a fund’s assets minus its liabilities, divided by the number of outstanding shares, so it represents what each share would be worth if the fund sold everything and paid its debts. Investors use it like a per-share “break-up” price to compare against the market trading price — if shares trade below NAV per share they may be seen as discounted, above it as a premium.

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Accepted by SEC EDGAR 04/06/2026 - 04:26 PM Learn about SEC filing dates

FAQ

What is CMU's tender offer size?

The tender offer is for up to 50% of outstanding common shares, equal to 12,746,391 shares. This is the maximum number the Fund will seek to purchase under the Offer dated April 6, 2026.

What price will CMU pay for shares in the offer?

CMU will pay an amount per share equal to 99% of net asset value per share as of the Expiration Date, net to the seller in cash, plus unpaid dividends accrued through May 5, 2026.

When did the CMU tender offer begin?

The Offer commenced on April 6, 2026. Related tender offer documents, including the Offer to Purchase and Letter of Transmittal, were filed with the Schedule TO and are attached as exhibits.

How can CMU shareholders obtain offer materials?

Shareholders can obtain the Offer to Purchase and Letter of Transmittal free of charge via the SEC website at www.sec.gov or by contacting the Fund, as stated in the Schedule TO amendment.

Are there conditions to the availability of consideration in CMU's Offer?

The Schedule TO states there are no material conditions to the availability of consideration for the Offer, except as set forth in the Offer to Purchase. Specific Offer conditions are in the Offer to Purchase.

united states
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

SCHEDULE TO

TENDER OFFER STATEMENT UNDER SECTION 14(D)(1) OR 13(E)(1)
OF THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

MFS High Yield Municipal Trust
(Name of Subject Company (Issuer))

MFS High Yield Municipal Trust
(Name of Filing Person (Issuer))

Common Shares, Without Par
(Title of Class of Securities)

59318E102
(CUSIP Number of Class of Securities)

Christopher R. Bohane
Massachusetts Financial Services Company
111 Huntington Avenue
Boston, MA 02199
Telephone: (617) 954-5000

(Name, address and telephone number of person authorized to receive notices and communications on behalf of filing persons)

With a Copy to:

David C. Sullivan
Ropes & Gray LLP
Prudential Tower
800 Boylston Street
Boston, MA 02199-3600
Telephone: (617) 951-7000

☐ Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

	☐	third party tender offer subject to Rule 14d-1.
	☒	issuer tender offer subject to Rule 13e-4.
	☐	going-private transaction subject to Rule 13e-3.
	☐	amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer. ☐

If applicable, check the appropriate box(es) below to designate the appropriate rule provision(s) relied upon:

	☐	Rule 13e-4(i) (Cross-Border Issuer Tender Offer)
	☐	Rule 14d-1(d) (Cross-Border Third-Party Tender Offer)

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explanatory note

This filing supplements the Schedule TO filed on March 04, 2026 regarding the communications made for the commencement of a tender offer (the “Offer”) on April 6, 2026 by MFS High Yield Municipal Trust, a closed-end management investment company (the “Fund”), to purchase for cash up to 50% or 12,746,391 shares of the Fund’s outstanding common shares (the “Shares”) upon the terms and subject to the conditions of the Offer.

This Amendment No. 1 to Schedule TO is intended to satisfy the requirements pursuant to Rule 13e-4(c)(3) of the Exchange Act.

Forward-Looking Statements

This document contains statements regarding plans and expectations for the future that constitute forward-looking statements within The Private Securities Litigation Reform Act of 1995. All statements other than statements of historical fact are forward-looking and can be identified by the use of words such as “may,” “will,” “expect,” “anticipate,” “estimate,” “believe,” “continue,” or other similar words. Such forward-looking statements are based on the Fund’s current plans and expectations, are not guarantees of future results or performance, and are subject to risks and uncertainties that could cause actual results to differ materially from those described in the forward-looking statements. All forward-looking statements are as of the date of this release only; the Fund undertakes no obligation to update or review any forward-looking statements. You are urged to carefully consider all such factors.

Additional Information and Where to Find It

The Offer referenced in this communication commenced on April 6, 2026. This announcement is for informational purposes only and is neither an offer to purchase nor a solicitation of an offer to sell Shares in the Fund, nor is it a solicitation of any proxy. This announcement is not a substitute for any materials that the Fund will file with the SEC.

The Fund filed a tender offer statement on Schedule TO, together with other related tender offer documents, including a letter of transmittal, in connection with the Offer. These documents contain important information about the Fund and the Offer. You are urged to read these documents carefully and in their entirety before making any decision regarding tendering your Shares. These documents are available to the Fund’s shareholders at no expense to them and will also be available for free at the SEC’s website at www.sec.gov.

This Schedule TO is not a prospectus, circular, or representation intended for use in the purchase or sale of Shares in the Fund. Shares of the Fund are not FDIC-insured and are not deposits or other obligations of, or guaranteed by, any bank. Shares of the Fund involve investment risk, including possible loss of principal. For more complete information about the Fund, including risks, charges, and expenses, please see the Fund’s annual and semi-annual shareholder reports. The Fund’s filings with the SEC are also available to the public from commercial document-retrieval services and at the website maintained by the SEC at www.sec.gov.

The Fund is a closed-end fund. Common shares of the Fund are only available for purchase/sale on the New York Stock Exchange at the current market price. Common shares may trade at a discount to net asset value.

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Items 1 through 9.

This Tender Offer Statement on Schedule TO is filed by MFS High Yield Municipal Trust, a Massachusetts business trust registered under the Investment Company Act of 1940, as amended, as a closed-end management investment company (the “Fund”). This Schedule TO relates to the Fund’s offer to purchase for cash up to 50% or 12,746,391 shares of its outstanding common shares, without par value (the “Common Shares”), upon the terms and subject to the conditions set forth in the Fund’s Offer to Purchase dated April 6, 2026 (the “Offer to Purchase”) and the related Letter of Transmittal (the “Letter of Transmittal” which, together with the Offer to Purchase constitute the “Offer”), copies of which are attached hereto as Exhibits (a)(1)(i) and (a)(1)(ii), respectively. The price to be paid for the Common Shares is an amount per share, net to the seller in cash, equal to 99% of the net asset value per share as of the Expiration Date (as defined in the Offer), plus any unpaid dividends accrued through May 5, 2026, or such later date to which the Offer is extended. There are no material conditions to the availability of consideration for purposes of this Offer, except as set forth in the Offer to Purchase. The information set forth in the Offer to Purchase and the related Letter of Transmittal is incorporated herein by reference with respect to Items 1 through 9 of this Schedule TO.

Item 10.

Not Applicable

Item 11.

(a)(1) The information set forth in the Offer to Purchase under “Interests of the Trustees and Officers; Transactions and Arrangements Concerning the Shares” is incorporated herein by reference.

(a)(2) The information set forth in the Offer to Purchase under “Legal Matters; Regulatory Approvals” is incorporated herein by reference.

(a)(3) Not applicable.

(a)(4) Not applicable.

(a)(5) None.

(c) Not applicable.

Items 12. EXHIBITS

Item 12 of the Schedule TO is hereby amended and supplemented to add the following exhibits:

Exhibit No. Document

(a)(1)(i)	Offer to Purchase dated April 6, 2026.
(a)(1)(ii)	Letter of Transmittal.
(a)(1)(iii)	Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.

 -4-

(a)(1)(iv)	Letter to Clients.
(a)(1)(v)	Notice of Withdrawal.
(a)(2)	None.
(a)(3)	Not Applicable.
(a)(4)	Not Applicable.
(a)(5)(iii)	Press Release issued on April 6, 2026.
(d)	None.
(g)	None.
(h)	None.
(s)	Filing Fee Table

Item 13.

Not applicable.

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SIGNATURE

After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

		MFS High Yield Municipal Trust
		By:		/s/ Christopher R. Bohane
		Name:		Christopher R. Bohane
		Title:		Assistant Secretary and Assistant Clerk

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