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): December 14, 2022

BAIN CAPITAL SPECIALTY FINANCE, INC.

(Exact name of Registrant as Specified in Its Charter)

Registrant’s telephone number, including area code: (617) 516-2000

                 N/A                  

(Former Name or Former Address, if Changed Since Last Report)

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 (see General Instruction A.2. below):

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. ¨

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

Item 1.01. Entry into a Material Definitive Agreement.

On December 14, 2022, Bain Capital Specialty Finance, Inc. (the “Company”) entered into the Increasing Lender/Joinder Lender Agreement (the “Joinder Agreement”), dated as of December 14, 2022, among the Company, Zions Bancorporation, N.A., DBA California Bank & Trust, as assuming lender, MUFG Union Bank, N.A., as an issuing bank, and Sumitomo Mitsui Banking Corporation, as administrative agent and an issuing bank, pursuant to Section 2.08(e) of the Senior Secured Revolving Credit Agreement, dated as of December 24, 2021 (as amended, supplemented, amended and restated, or otherwise modified from time to time, the “Credit Agreement”), among the Company, Sumitomo Mitsui Banking Corporation, as administrative agent, and the lenders and issuing bank party thereto.

The Joinder Agreement provides for, among other things, an upsize in the total commitments from lenders under the revolving credit facility governed by the Credit Agreement from $635,000,000 to $665,000,000.

The description above is only a summary of the material provisions of the Joinder Agreement and is qualified in its entirety by reference to a copy of the Joinder Agreement, which will be filed with the Company’s Annual Report on Form 10-K for the year ending December 31, 2022.

SIGNATURES

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