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

Rhea-AI Filing Summary

RiverNorth Capital Management, LLC filed an amended Schedule 13G reporting ownership of 2,579,075 shares of MFS High Yield Municipal Trust common shares, representing 10.12% of the class as of 09/30/2025. RiverNorth states it has sole voting and dispositive power over the reported shares and that the holdings were acquired and are held in the ordinary course of business, not to influence control. The filing lists RiverNorth's address in West Palm Beach, its Delaware organization, and is signed by Marcus Collins as General Counsel and Chief Compliance Officer on 10/07/2025.

Positive

• Material stake disclosed: RiverNorth reports 2,579,075 shares ( 10.12% ), providing clarity on ownership concentration
• Sole voting and dispositive power: Reporting firm explicitly holds both voting and dispositive authority for the reported shares

Negative

• Potential market impact: A >10% position by a single manager could influence liquidity or price if traded
• No additional context on beneficiaries: The filing notes others have rights to proceeds but does not identify them, limiting transparency

Insights

Institutional Ownership Analyst

Institutional holder reports a >10% stake with sole voting and dispositive power.

The filing shows RiverNorth directly holds 2,579,075 shares, equal to 10.12% of the class, and reports sole voting and sole dispositive authority for those shares. That concentration can affect shareholder dynamics because a single registered investment adviser now holds a material block.

Risks and dependencies include any future trading by this holder that could move supply/demand; monitor any further amendments or a Schedule 13D if intentions change within the next several months.

Compliance & Regulatory Specialist

Filing complies with Schedule 13G reporting conventions for passive investors.

The statement certifies the securities were acquired in the ordinary course of business and not to influence control, consistent with Rule 13d-1(b) passive reporting. The signer is the firm CCO, providing the required certification.

Watch for any change in status: if actions suggest control or activist intent, filing requirements would escalate to Schedule 13D; check filings after 10/07/2025 for updates.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 2)

MFS HIGH YIELD MUNICIPAL TRUST

(Name of Issuer)

Shares of Beneficial Interest

(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

RIVERNORTH CAPITAL MANAGEMENT, 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 2,579,075.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,579,075.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,579,075.00

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)

10.12 %

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, 24TH FLOOR, BOSTON, MA, 02199
Item 2.
(a)	Name of person filing: RiverNorth Capital Management, LLC
(b)	Address or principal business office or, if none, residence: 360 S. Rosemary Avenue, Ste. 1420 West Palm Beach, Florida 33401
(c)	Citizenship: Delaware
(d)	Title of class of securities: Shares of Beneficial Interest
(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: 2,579,075
(b)	Percent of class: 10.12 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 2,579,075
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 2,579,075
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. Other persons have the right to receive the proceeds from the sale of the securities reported herein.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. Not applicable.
Item 8.	Identification and Classification of Members of the Group.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group. Not applicable.
Item 9.	Notice of Dissolution of Group.
	Notice of dissolution of a group may be furnished as an exhibit stating the date of the dissolution and that all further filings with respect to transactions in the security reported on will be filed, if required, by members of the group, in their individual capacity. See Item 5. 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.

RIVERNORTH CAPITAL MANAGEMENT, LLC

Signature:	/s/ Marcus Collins
Name/Title:	Marcus Collins, General Counsel and Chief Compliance Officer
Date:	10/07/2025

FAQ

What stake does RiverNorth report in CMU?

RiverNorth reports beneficial ownership of 2,579,075 shares, equal to 10.12% of the class.

Does RiverNorth have voting control over the CMU shares?

Yes. The filing states RiverNorth has sole voting power and sole dispositive power for the 2,579,075 shares.

When is the ownership percentage effective for CMU?

The event date requiring the filing is 09/30/2025, and the amendment was signed on 10/07/2025.

Was the position acquired to influence control of CMU?

No. RiverNorth certified the securities were acquired and are held in the ordinary course of business and not to change or influence control.

Who signed the Schedule 13G/A for RiverNorth?

The filing is signed by Marcus Collins, General Counsel and Chief Compliance Officer, on 10/07/2025.