8-K

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): September 30, 2024

NewMountain Finance Corporation

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including

area code: (212

) 720-0300

None

(Former name or former address, if changedsince 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):

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

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. ¨

Amendment to NMFC Credit Facility

New Mountain Finance Corporation (the “Company”) previously entered into the Amended and Restated Senior Secured Revolving Credit Agreement, dated as of June 4, 2021 (together with the exhibits and schedules thereto, and as amended from time to the time, the “RevolvingCredit Agreement”), by and among the Company, as the borrower, Goldman Sachs Bank, USA, as the administrative agent and syndication agent, and the lenders party thereto.

On September 30, 2024, the Company entered into the Second Amended and Restated Senior Secured Revolving Credit Agreement (the “SecondAmended and Restated Revolving Credit Agreement,” and the revolving credit facility thereunder the “NMFCCredit Facility”), by and among the Company, Sumitomo Mitsui Banking Corporation, as administrative agent, sole lead arranger, and sole book runner (the “Administrative Agent”), and the lenders party thereto, which amended and restated the Revolving Credit Agreement. Unless otherwise indicated, the terms used below have the meanings ascribed in the Second Amended and Restated Revolving Credit Agreement.

The Second Amended and Restated Revolving Credit Agreement amended the NMFC Credit Facility to, among other things, (i) increase the total commitments to $638,500,000; (ii) extend the maturity to September 2029 (for $527,100,000 of the commitments (the “extended commitments”)); and (iii) change the applicable margin to 1.90% for the extended commitments.

The description above is qualified in its entirety by reference to the Second Amended and Restated Revolving Credit Agreement, which will be filed as an exhibit to the Company’s Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2024.

Termination of DB Credit Facility

On September 30, 2024, the Company terminated in full the Loan Financing and Servicing Agreement, dated as of December 14, 2018 (as amended from time to time, the “Loan Financing and Servicing Agreement”, and the credit facility thereunder the “DB CreditFacility”) by and among New Mountain Finance DB, L.L.C., as borrower, the Company, as servicer and as equityholder, Deutsche Bank AG, New York Branch, as the facility agent and as a committed lender (the “Lenders”), U.S. Bank Trust Company, National Association, as the collateral agent, and U.S. Bank National Association, as the collateral custodian. In connection with the termination of the DB Credit Facility, the Company also terminated the security interest over the collateral granted to the Lenders pursuant to the Loan Financing and Servicing Agreement and the other Transaction Documents (as defined in the Loan Financing and Servicing Agreement).

The DB Credit Facility was terminated concurrent with the satisfaction of all obligations and liabilities of the Company to the Lenders thereunder, including, without limitation, payments of principal and interest, other fees, breakage costs and other amounts owing to the Lenders.

The disclosure set forth above under Item 1.01 is incorporated by reference herein.

d) Exhibits.

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.

Date: October 3, 2024