MFS High Yield Municipal (NYSE: CMU) holder Bulldog drops under 5%

Rhea-AI Filing Summary

Bulldog Investors, LLP and its principals have reduced their stake in MFS High Yield Municipal Trust (CMU) and are no longer 5% holders. Based on 12,746,391 common shares outstanding as of May 6, 2026, Bulldog Investors is deemed to beneficially own 100,155 shares, or 0.79% of CMU. Phillip Goldstein is deemed to beneficially own 133,190 shares, or 1.04%, while Andrew Dakos is deemed to beneficially own 90,245 shares, or 0.71%, through their roles at Bulldog.

Since the prior filing, accounts managed by Bulldog disposed of 141,450 shares at $3.6400, 79,573 shares at $3.6456, and 1,410,919 shares at $3.71. The reporting persons state they ceased to be beneficial owners of more than 5% of CMU’s common stock on May 6, 2026, following tender offer results disclosed in the company’s press release.

Insights

Closed-end fund governance analyst

Bulldog Investors has scaled back its CMU position below 5%, reducing its reporting status.

Bulldog Investors, LLP, along with Phillip Goldstein and Andrew Dakos, reports beneficial ownership levels of 0.79%, 1.04%, and 0.71% of CMU respectively, calculated against 12,746,391 shares outstanding as of May 6, 2026. They attribute their status change to tender offer results.

The filing lists recent sales of 141,450, 79,573, and 1,410,919 shares between prices of $3.6400 and $3.71. This moves Bulldog from a large holder above the 5% threshold to a smaller, still visible shareholder. Future filings may clarify whether their CMU position stabilizes or continues to decline.

Key Figures

Shares outstanding: 12,746,391 shares Bulldog beneficial ownership: 100,155 shares (0.79%) Goldstein beneficial ownership: 133,190 shares (1.04%) +4 more

7 metrics

Shares outstanding 12,746,391 shares CMU common stock outstanding as of May 6, 2026

Bulldog beneficial ownership 100,155 shares (0.79%) Bulldog Investors, LLP stake in CMU as of May 6, 2026

Goldstein beneficial ownership 133,190 shares (1.04%) Phillip Goldstein stake in CMU as of May 6, 2026

Dakos beneficial ownership 90,245 shares (0.71%) Andrew Dakos stake in CMU as of May 6, 2026

Large disposal 1 141,450 shares at $3.6400 CMU shares disposed on May 4, 2026

Large disposal 2 79,573 shares at $3.6456 CMU shares disposed on May 4, 2026

Large disposal 3 1,410,919 shares at $3.71 CMU shares disposed on May 6, 2026

Key Terms

beneficial owner, Schedule 13D, tender offer, dispositive power, +1 more

5 terms

beneficial owner financial

"Bulldog Investors, LLP is deemed to be the beneficial owner of 100,155 shares of CMU"

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

Schedule 13D regulatory

"This Constitutes Amendment #14 to the filed July 17, 2023"

A Schedule 13D is a legal document that investors file with regulators when they buy a large enough stake in a company to potentially influence its management or decisions. It provides details about the investor’s intention, ownership stake, and plans, helping other investors understand who is gaining control and what their motives might be.

tender offer financial

"based on the tender offer results set forth in the Company's press release published 5/6/26"

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.

dispositive power financial

"Bulldog Investors, LLP has sole power to dispose of and vote 10,394 shares"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

shared voting power financial

"Bulldog Investors, LLP has shared power to dispose and vote 89,761 shares"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 14)

MFS High Yield Municipal Trust

(Name of Issuer)

Common Stock

(Title of Class of Securities)

59318E102

(CUSIP Number)

Phillip Goldstein
250 Pehle Ave., Suite 708
Saddle Brook, NJ, 07663
914 747-5262

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

05/06/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

schemaVersion:

SCHEDULE 13D

CUSIP Number(s): 59318E102

1

Name of reporting person

Bulldog Investors, LLP

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 10,394.00
8	Shared Voting Power 89,761.00
9	Sole Dispositive Power 10,394.00
10	Shared Dispositive Power 89,761.00

11

Aggregate amount beneficially owned by each reporting person

100,155.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.79 %

14

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13D

CUSIP Number(s): 59318E102

1

Name of reporting person

Phillip Goldstein

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 10,394.00
8	Shared Voting Power 122,796.00
9	Sole Dispositive Power 10,394.00
10	Shared Dispositive Power 122,796.00

11

Aggregate amount beneficially owned by each reporting person

133,190.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.04 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

CUSIP Number(s): 59318E102

1

Name of reporting person

Andrew Dakos

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 90,245.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 90,245.00

11

Aggregate amount beneficially owned by each reporting person

90,245.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.71 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock
(b)	Name of Issuer: MFS High Yield Municipal Trust
(c)	Address of Issuer's Principal Executive Offices: 111 Huntington Avenue, Boston, MASSACHUSETTS , 02199.
Item 1 Comment: This Constitutes Amendment #14 to the schedule 13D filed July 17, 2023. Except as specifically set forth herein, the schedule 13D remains unmodified.
Item 5.	Interest in Securities of the Issuer
(a)	As per the tender results in the press release on 5/6/26 there were 12,746,391 shares of common stock outstanding as of May 6, 2026. The percentages set forth herein were derived using such number. Phillip Goldstein and Andrew Dakos own Bulldog Investors, LLP, a registered investment advisor. As of May 6, 2026, Bulldog Investors, LLP is deemed to be the beneficial owner of 100,155 shares of CMU (representing 0.79% of CMU's outstanding shares) solely by virtue of Bulldog Investors, LLP's power to direct the vote of, and dispose of, these shares. As of May 6, 2026, Mr. Goldstein is deemed to be the beneficial owner of 133,190 shares of CMU (representing 1.04% of CMU's outstanding shares) and Mr. Dakos is deemed to be the beneficial owner of 90,245 Shares of CMU (representing 0.71% of CMU's outstanding shares) by virtue of their power to direct the vote of, and dispose of, these shares.
(b)	Bulldog Investors, LLP has sole power to dispose of and vote 10,394 shares. Bulldog Investors, LLP has shared power to dispose and vote 89,761 shares. Certain of Bulldog Investors, LLP's clients (none of whom beneficially own more than 5% of CMU's shares) share this power with Bulldog Investors. Messrs. Goldstein and Dakos are partners of Bulldog Investors, LLP.
(c)	Since the last filing on 5/5/26, the following shares were disposed of: Date Shares Price 5/4/26 (141,450) 3.6400 5/4/26 (79,573) 3.6456 5/6/26 (1,410,919) 3.71
(d)	Clients of Bulldog Investors, LLP and the owners of accounts reflected herein are entitled to receive any dividends or sales proceeds.
(e)	The Reporting Persons ceased to be the beneficial owner of more than 5% of CMU's common stock on May 6, 2026 based on the tender offer results set forth in the Company's press release published 5/6/26.

SIGNATURE

After reasonable 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.

Bulldog Investors, LLP

Signature:	/s/ Andrew Dakos
Name/Title:	Andrew Dakos, Partner
Date:	05/07/2026

Phillip Goldstein

Signature:	/s/ Phillip Goldstein
Name/Title:	Phillip Goldstein
Date:	05/07/2026

Andrew Dakos

Signature:	/s/ Andrew Dakos
Name/Title:	Andrew Dakos
Date:	05/07/2026

FAQ

How many CMU shares are outstanding according to this Bulldog Investors filing?

The filing states CMU had 12,746,391 common shares outstanding as of May 6, 2026. All reported ownership percentages for Bulldog Investors and its principals are calculated using this share count as the base.

What percentage of CMU does Bulldog Investors, LLP currently beneficially own?

Bulldog Investors, LLP is deemed to beneficially own 100,155 CMU shares, representing 0.79% of the outstanding common stock. This ownership reflects Bulldog’s power to vote and dispose of those shares as of May 6, 2026.

What are Phillip Goldstein’s and Andrew Dakos’s beneficial ownership stakes in CMU?

Phillip Goldstein is deemed to beneficially own 133,190 CMU shares (1.04%), while Andrew Dakos is deemed to beneficially own 90,245 shares (0.71%). Their stakes arise from their ability to direct voting and disposition of these shares through Bulldog Investors.

When did Bulldog Investors cease to be a 5% beneficial owner of CMU?

The reporting persons state they ceased to be beneficial owners of more than 5% of CMU’s common stock on May 6, 2026, based on tender offer results disclosed in the company’s May 6, 2026 press release.

What recent CMU share sales are disclosed for Bulldog-managed accounts?

The filing lists disposals of 141,450 shares at $3.6400, 79,573 shares at $3.6456, and 1,410,919 shares at $3.71. These transactions occurred between May 4 and May 6, 2026 and reduced Bulldog-managed holdings.

How is voting and dispositive power over CMU shares allocated for Bulldog Investors?

Bulldog Investors, LLP reports sole power to vote and dispose of 10,394 CMU shares and shared power over 89,761 shares. Certain Bulldog clients share this power, and none individually beneficially own more than 5% of CMU.