[SCHEDULE 13G/A] MFS HIGH YIELD MUNICIPAL TRUST SEC Filing

Rhea-AI Filing Summary

Sit Investment Associates, Inc. and its subsidiary Sit Fixed Income Advisors II, LLC report shared beneficial ownership of 1,045,340 shares of MFS High Yield Municipal Trust common stock, representing 4.1% of the class based on 25,492,782 shares outstanding as of May 31, 2025. The filing discloses shared voting and shared dispositive power over these shares and states the securities are held in client accounts managed by the advisers. The reporting entities assert the holdings were acquired and are held in the ordinary course of business and, pursuant to Rule 13d-4, disclaim beneficial ownership of the securities. The Schedule 13G/A covers the event date 09/30/2025 and is signed by Paul E. Rasmussen on 10/02/2025.

Positive

• 1,045,340 shares reported, representing 4.1% of class
• Ownership calculation uses issuer figure of 25,492,782 shares outstanding as of May 31, 2025
• Filing discloses shared voting and shared dispositive power, providing clarity on control
• Includes a Rule 13d-4 disclaimer and certification that holdings are in the ordinary course of business
• Signed and dated disclosure: event date 09/30/2025, signature dated 10/02/2025

Negative

• None.

Insights

Governance Analyst

Advisers report a non-controlling, transparent stake of 4.1% in CMU.

The filing shows shared voting and dispositive power over 1,045,340 shares held in client accounts, which signals portfolio-level exposure rather than direct strategic control.

This level of ownership is below the 5% threshold that often triggers closer investor scrutiny, so the position is informational rather than control-oriented.

Securities Compliance Attorney

Report follows Schedule 13G rules and includes a Rule 13d-4 disclaimer.

The filing documents adherence to disclosure requirements: it identifies the reporting persons, quantifies ownership as 4.1% of the class using the issuer's 25,492,782 outstanding-share figure, and includes the required certification about ordinary-course holdings.

By disclaiming beneficial ownership under Rule 13d-4, the advisers clarify these are client account holdings; the statement reduces regulatory concern about an intent to influence issuer control.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

MFS High Yield Municipal Trust

(Name of Issuer)

Common Stock

(Title of Class of Securities)

59318E102

(CUSIP Number)

09/30/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 59318E102

1

Names of Reporting Persons

Sit Investment Associates, Inc.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

MINNESOTA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,045,340.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,045,340.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,045,340.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

4.1 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP No. 59318E102

1

Names of Reporting Persons

Sit Fixed Income Advisors II, LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,045,340.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,045,340.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,045,340.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

4.1 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: MFS High Yield Municipal Trust
(b)	Address of issuer's principal executive offices: 111 Huntington Avenue, Boston, Massachusetts 02199
Item 2.
(a)	Name of person filing: Sit Investment Associates, Inc. Sit Fixed Income Advisors II, LLC
(b)	Address or principal business office or, if none, residence: c/o Sit Investment Associates, Inc. 80 South Eighth Street, Suite 3300 Minneapolis, MN 55402
(c)	Citizenship: Sit Investment Associates, Inc. Minnesota Corporation Sit Fixed Income Advisors II, LLC Delaware LLC
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 59318E102
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: See response to item 9 on each cover page.
(b)	Percent of class: See response to item 11 on each cover page.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See response to item 5 on each cover page.
	(ii) Shared power to vote or to direct the vote: See response to item 6 on each cover page.
	(iii) Sole power to dispose or to direct the disposition of: See response to item 7 on each cover page.
	(iv) Shared power to dispose or to direct the disposition of: See response to item 8 on each cover page. The ownership percentages reported are based on 25,492,782 shares of common stock outstanding as of May 31, 2025 as reported in the Issuer's Report on Form N-CSRS filed with the Securities Exchange Commission. Sit Investment Associates, Inc. ("SIA") is an investment adviser registered under section 203 of the Investment Advisers Act of 1940. Sit Fixed Income Advisors II, LLC ("SFI") is an investment adviser registered under section 203 of the Investment Advisers Act of 1940 and a subsidiary of SIA. SIA and SFI provide investment management services to client accounts ("Accounts"). In their roles as investment advisers SIA and SFI possess shared voting and investment power over securities of the Issuer described in this schedule 13G owned by the Accounts and may be deemed to be the beneficial owner of such shares of the Issuer owned by the Accounts. All securities reported in this schedule 13G are owned by the Accounts. Pursuant to Rule 13d-4 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), SIA and SFI disclaim beneficial ownership of such securities.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

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.

Sit Investment Associates, Inc.

Signature:	/s/ Paul E. Rasmussen
Name/Title:	Paul Rasmussen / Vice President
Date:	10/02/2025

Sit Fixed Income Advisors II, LLC

Signature:	/s/ Paul E. Rasmussen
Name/Title:	Paul Rasmussen / Vice President
Date:	10/02/2025

Exhibit Information

Exhibit A - Joint Filing Agreement

FAQ

What stake in MFS High Yield Municipal Trust (CMU) did Sit Investment report?

The filing reports shared beneficial ownership of 1,045,340 shares, equal to 4.1% of CMU's common stock.

On what outstanding-share basis was the 4.1% calculated?

The percentage is based on 25,492,782 shares outstanding as disclosed in the issuer's Form N-CSRS as of May 31, 2025.

Do Sit Investment and Sit Fixed Income Advisors claim control of CMU?

No. The filing states the holdings are in client accounts and the reporting entities disclaim beneficial ownership under Rule 13d-4.

What voting and dispositive powers are reported?

Both reporting persons report 0 sole voting/dispositive power and 1,045,340 shares of shared voting and shared dispositive power.

When was the Schedule 13G/A signed?

The signature by Paul E. Rasmussen is dated 10/02/2025; the event date requiring filing is 09/30/2025.