X0202 SCHEDULE 13D/A 001504304-23-000019 0001504304 XXXXXXXX LIVE 14 Common Stock 05/06/2026 false 0000809844 59318E102 MFS High Yield Municipal Trust

111 Huntington Avenue Boston MA 02199

Phillip Goldstein 914 747-5262 250 Pehle Ave. Suite 708 Saddle Brook NJ 07663 0001504304 N Bulldog Investors, LLP WC N DE 10394.00 89761.00 10394.00 89761.00 100155.00 N 0.79 IA Y Phillip Goldstein WC N X1 10394.00 122796.00 10394.00 122796.00 133190.00 N 1.04 IN Y Andrew Dakos WC N X1 0.00 90245.00 0.00 90245.00 90245.00 N 0.71 IN Common Stock MFS High Yield Municipal Trust 111 Huntington Avenue Boston MA 02199 This Constitutes Amendment #14 to the schedule 13D filed July 17, 2023. Except as specifically set forth herein, the schedule 13D remains unmodified. 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. 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. 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 Clients of Bulldog Investors, LLP and the owners of accounts reflected herein are entitled to receive any dividends or sales proceeds. 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. Bulldog Investors, LLP /s/ Andrew Dakos 05/07/2026 Phillip Goldstein /s/ Phillip Goldstein 05/07/2026 Andrew Dakos /s/ Andrew Dakos 05/07/2026