New Mountain Finance Corp

false 0001496099 0001496099 2026-10-20 2026-10-20 0001496099 nmfc:CommonStockParValue0.01PerShareMember 2026-10-20 2026-10-20 0001496099 nmfc:Sec8.250NotesDue2028Member 2026-10-20 2026-10-20 iso4217:USD xbrli:shares iso4217:USD xbrli:shares 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): October 20, 2026 New Mountain Finance Corporation (Exact name of registrant as specified in its charter) Delaware 814-00832 27-2978010 (State or other jurisdiction of incorporation or organization) (Commission File Number) (IRS Employer Identification Number) 1633 Broadway , 48th Floor , New York , NY 10019 (Address of principal executive offices) (Zip code) Registrant’s telephone number, including area code: (212) 720-0300 None (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): ¨ 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: Title of each class Trading Symbol(s) Name of each exchange on which registered Common stock, par value $0.01 per share NMFC NASDAQ Global Select Market 8.250% Notes due 2028 NMFCZ NASDAQ Global Select Market 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. Extension of Stock Repurchase Program On October 26, 2026, New Mountain Finance Corporation (the “ Company ”) issued a press release to announce that on October 20, 2026 its board of directors approved an extension of the Company’s stock repurchase program. The press release is attached as Exhibit 99.1 to this Form 8-K and is incorporated herein by reference. Item 9.01. Financial Statements and Exhibits. d) Exhibits. Exhibit Number Description 99.1 Press Release, dated October 26, 2026 104 Cover Page Interactive Data File (embedded within the Inline XBRL document). SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this Current Report on Form 8-K to be signed on its behalf by the undersigned hereunto duly authorized. NEW MOUNTAIN FINANCE CORPORATION Date: October 26, 2026 By: /s/ Eric Kane Name: Eric Kane Title: Corporate Secretary