UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported): August 9, 2025

EATON VANCE SENIOR INCOME TRUST

(Exact name of registrant as specified in its charter)

Massachusetts

(State or other jurisdiction

of incorporation)

811-09013

(Commission File Number)

04-3435040

(IRS Employer

Identification No.)

One Post Office Square

Boston, Massachusetts

(Address of principal executive offices)

02109

(Zip Code)

(617) 482-8260
(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

□ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

□ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

□ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

□ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Titles of Each Class	Trading Symbol	Name of exchange on which registered
Common Shares of Beneficial Interest, $0.01 par value	EVF	NYSE

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company □

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. □

Item 8.01 Other Events

Mr. Mark R. Fetting, who served as Chairperson of the Board of Trustees of the registrant (the “Board”), unexpectedly passed away on August 9, 2025. Ms. Susan J. Sutherland is serving as acting Chairperson of the Board. Effective as of August 12, 2025, the Board has reduced the size of the Board from ten to nine members.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

EATON VANCE SENIOR INCOME TRUST

By: /s/ Deidre E. Walsh

Name: Deidre E. Walsh

Title: Vice President & Chief Legal Officer

Date: August 14, 2025

Eaton Vance Senior Income Trust 8-K