UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of

the Securities Exchange Act of 1934 (Amendment No. )

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

☐	Preliminary Proxy Statement

☐	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☒	Definitive Proxy Statement

☐	Definitive Additional Materials

☐	Soliciting Material under §240.14a-12

New Mountain Finance Corporation

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

☒	No fee required.

☐	Fee paid previously with preliminary materials.

☐	Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11

New Mountain Finance Corporation

1633 Broadway, 48th Floor

New York, New York 10019

March 27, 2026

Dear Stockholder:

You are cordially invited to attend the 2026 Annual Meeting of Stockholders (“Annual Meeting”) of New Mountain Finance Corporation (“NMFC” or the “Company”) to be held on May 12, 2026 at 10:30 a.m., Eastern Time. You will be able to participate in the Annual Meeting, vote and submit your questions via live webcast by visiting www.virtualshareholdermeeting.com/NMFC2026. Prior to the Annual Meeting you will be able to vote electronically at www.proxyvote.com.

The notice of the Annual Meeting and the proxy statement provide an outline of the business to be conducted at the Annual Meeting. At the Annual Meeting, the stockholders of NMFC will be asked to: (i) elect three directors to the board of directors of NMFC to serve for a term of three years, or until their respective successors are duly elected and qualify; (ii) ratify the appointment of Deloitte & Touche LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026; and (iii) transact such other business that may properly come before the Annual Meeting.

It is important that your shares be represented at the Annual Meeting. If you are unable to participate in the Annual Meeting during the scheduled time, I urge you to follow the instructions on the Notice of Internet Availability of Proxy Materials to vote your proxy on the Internet. I encourage you to vote via the Internet, as it saves us significant time and processing costs. However, on the Notice of Internet Availability of Proxy Materials, you will also find instructions on how to request a hard copy of the Proxy Statement and proxy card free of charge and you may vote your proxy by returning your proxy card to us after you request the hard copy materials. Your vote is important.

To vote or to submit your questions during the Annual Meeting, please log on to www.virtualshareholdermeeting.com/NMFC2026. You will need to enter the 16-digit control number on your notice of the Annual Meeting. Your vote is important to us.

	Sincerely yours,



	John R. Kline
	President and Chief Executive Officer

New Mountain Finance Corporation

1633 Broadway, 48th Floor

New York, New York 10019

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

AND INTERNET AVAILABILITY OF PROXY MATERIALS

TO BE HELD ON MAY 12, 2026

To the Stockholders of New Mountain Finance Corporation:

A meeting (the “Annual Meeting”) of stockholders of New Mountain Finance Corporation (“NMFC” or the “Company”) will be held on May 12, 2026 at 10:30 a.m., Eastern Time. We are very pleased that this year’s Annual Meeting will be a completely virtual meeting of stockholders, which will be conducted via live webcast. It is important to note that stockholders have the same rights and opportunities by participating in a virtual meeting, as they would if attending an in-person meeting. You can participate in the Annual Meeting, vote and submit your questions during the Annual Meeting by visiting www.virtualshareholdermeeting.com/NMFC2026. You must have your 16-digit control number in order to access the Annual Meeting. The Annual Meeting will be held for the following purposes:

To elect three directors to the board of directors of NMFC who will each serve for a term of three years, or until their respective successors are duly elected and qualify;

To ratify the appointment of Deloitte & Touche LLP to serve as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026; and

To transact such other business as may properly come before the Annual Meeting.

You have the right to receive notice of, and to vote at, the Annual Meeting if you were a stockholder of record at the close of business on March 13, 2026. NMFC is furnishing the Proxy Statement and proxy card to its stockholders on the Internet, rather than mailing printed copies of those materials to each stockholder. If you received a Notice of Internet Availability of Proxy Materials by mail, you will not receive a printed copy of the Proxy Statement and proxy card unless you request them. Instead, the Notice of Internet Availability of Proxy Materials will instruct you as to how you may access and review the Proxy Statement, and vote your proxy, on the Internet.

Your vote is extremely important to us. If you are unable to attend the Annual Meeting, we encourage you to vote your proxy on the Internet by following the instructions provided on the Notice of Internet Availability of Proxy Materials. You may also request from us, free of charge, hard copies of the Proxy Statement and proxy card for the Company by following the instructions on the Notice of Internet Availability of Proxy Materials. In the event there are not sufficient votes for a quorum or to approve NMFC’s proposals at the time of the Annual Meeting, the Annual Meeting may be adjourned in order to permit further solicitation of proxies by NMFC.

	By Order of the board of directors,


	Eric Kane Corporate Secretary

New York, New York

March 27, 2026

This is an important meeting. To ensure proper representation at the Annual Meeting, please follow the instructions on the Notice of Internet Availability of Proxy Materials to vote your proxy via the Internet or request, complete, sign, date and return a proxy card. Even if you vote your shares prior to the Annual Meeting, you still may attend the Annual Meeting and vote your shares via the Internet.

New Mountain Finance Corporation

1633 Broadway, 48th Floor

New York, NY 10019

PROXY STATEMENT

2026 Annual Meeting

of Stockholders of New Mountain Finance Corporation

This Proxy Statement is furnished in connection with the solicitation of proxies by the board of directors of New Mountain Finance Corporation (“NMFC”, the “Company”, “we”, “us” or “our”) for use at the NMFC 2026 Annual Meeting (the “Annual Meeting”) to be held on May 12, 2026, at 10:30 a.m., Eastern Time. You can virtually attend the Annual Meeting online, vote your shares electronically and submit questions during the Annual Meeting by visiting www.virtualshareholdermeeting.com/NMFC2026, and at any postponements or adjournments thereof. You will need to enter the 16-digit control number on your notice of the Annual Meeting. It is important to note that shareholders have the same rights and opportunities by participating in a virtual meeting, as they would if attending an in-person meeting. This Proxy Statement is being provided to the stockholders of NMFC via the Internet on or about March 31, 2026. In addition, a Notice of Annual Meeting and a Notice of Internet Availability of Proxy Materials are being sent to our stockholders of record on or about March 31, 2026.

We encourage you to vote your shares of NMFC’s stock either by voting via the Internet while virtually attending the Annual Meeting, by telephone, or by granting a proxy (i.e., authorizing someone to vote your shares). Shares represented by duly executed proxies will be voted in accordance with your instructions. If you give no instructions on the proxy card, the shares covered by the proxy card will be voted “FOR” the matters listed in this Proxy Statement.

If you are a stockholder “of record” (i.e., you hold shares directly in your name), you may revoke a proxy at any time before it is exercised by notifying the proxy tabulator, Broadridge Shareholder Solutions, Inc., in writing, by submitting a properly executed, later-dated proxy, or by voting virtually at the Annual Meeting. Please send your notification to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717, and submit a properly executed, later-dated proxy or vote virtually at the Annual Meeting. Any stockholder of record attending the Annual Meeting may vote virtually whether or not he, she or it has previously voted his, her or its shares. If your shares are held for your account by a broker, bank or other institution or nominee (“Broker Securities”), you may vote such securities at the Annual Meeting only if you obtain proper written authority from your institution or nominee and present it at the Annual Meeting. All of our directors are encouraged to attend the Annual Meeting. Stockholders have no dissenters’ or appraisal rights in connection with any of the proposals described herein.

Stockholders of record may also vote either via the Internet or by telephone. Specific instructions to be followed by stockholders of record interested in voting via the Internet or the telephone are shown on the proxy card. The Internet and telephone voting procedures are designed to authenticate the voter’s identity and to allow stockholders to vote their shares and confirm that their instructions have been properly recorded.

TABLE OF CONTENTS


Information About the Annual Meeting		Page
Purpose of Annual Meeting		1
Shares		1
Quorum Required		1
Vote Required		1
Information Regarding this Solicitation		2
Control Persons and Principal Stockholders		2
Proposal 1: Election of Directors		6
Information About the Nominees and Directors		6
Nominees for Directors		7
Current Directors		11
Information about Executive Officers Who Are Not Directors		17
Director Independence		18
Board of Directors Leadership Structure		18
Board of Directors’ Role in Risk Oversight		19
Committees of the Board of Directors		20
Executive Sessions and Communication with the Board of Directors		22
Code of Ethics		23
Insider Trading Policies		23
Compensation of Directors		23
Compensation of Executive Officers		24
Indemnification Agreements		24
Certain Relationships and Transactions		24
Board of Directors Consideration of the Investment Advisory and Management Agreement		27
Proposal 2: Ratification of the Appointment of Deloitte & Touche LLP as NMFC’s Independent Registered Public Accounting Firm		29
Audit Committee Report		30
Other Business		32
Submission of Stockholder Proposals		32
Other Business		33
Annual Reports		33
Delivery of Proxy Materials		33
Privacy Notice		34

	Type of Ownership in NMFC	NMFC Shares	Percentage
Name	Type of Ownership in NMFC	Number⁽¹⁾	Percentage
Interested Directors:
Steven B. Klinsky⁽²⁾	Direct and Beneficial	12,330,153	12.52%
Robert A. Hamwee⁽³⁾	Direct and Beneficial	661,219	*
Adam B. Weinstein	Direct	738,856	*
John R. Kline	Direct	360,359	*
Independent Directors:
John P. Malfettone	Direct	77,500	*
Rome G. Arnold III	Direct	88,775	*
David Ogens⁽⁴⁾	Direct	257,556	*
Daniel B. Hébert	—	—	—
Barbara Daniel	—	—	—
Executive Officers Who Are Not Directors:
Kris Corbett	Direct	9,750	*
Laura C. Holson	Direct	81,029	*
Joseph W. Hartswell	Direct	15,556	*
All executive officers and directors as a group (12 persons)⁽⁵⁾	Direct and Beneficial	14,633,653	14.9%

	Dollar Range of Equity Securities Beneficially Owned in NMFC^(1)(2)(4)	Aggregate Dollar Range of Equity Securities in the Fund Complex^(1)(3)(4)
Interested Directors:
Steven B. Klinsky	Over $100,000	Over $100,000
Robert A. Hamwee	Over $100,000	Over $100,000
Adam B. Weinstein	Over $100,000	Over $100,000
John R. Kline	Over $100,000	Over $100,000

Name of Director	Name of Owners	Name of Investment	Title of Class	Dollar Range of Equity Securities⁽¹⁾

Independent Directors
Rome G. Arnold III	Arnold Family LLC		N/A—Single Class	Over $100,000 in each
		New Mountain Partners III, L.P.
		New Mountain Partners IV, L.P.
		New Mountain Partners V, L.P.
		New Mountain Partners VI, L.P.
		NMP III Continuation Feeder Fund, L.P.
		New Mountain Partners VII, L.P.

John P. Malfettone	Malfettone Family Trust	NMP VII Direct I-Feeder, LP		Over $100,000

Name, Address and Age	Position(s) Held with NMFC	Terms of Office and Length of Time Served	Principal Occupation(s) During Past Five Years	Number of Companies in Fund Complex Overseen by Director	Other Directorships Held by Director or Nominee for Director During Past Five Years
Interested Director
Steven B. Klinsky, 69	Chairman of the board of directors.	Class III Director since 2010; Term expires 2026.	Founder and Chief Executive Officer of New Mountain Capital, L.L.C. (private equity firm) from its inception in 1999 to present.	1	Board Member of American Investment Council (industry trade association) since 2011; Chairman of American Investment Council (industry trade association) from 2018 to 2021; Board Member of Gary Klinsky Children Centers (after school program) since 1993; Member of the Executive Council of (Raj & Kamala) Gupta Governance Jan 2019 Institute at Drexel University (humanitarian effort) since 2019; Advisory Member of The Gupta-Klinsky India Institute at The John Hopkins University (humanitarian effort) since 2021; Board Member of International Rescue Committee (humanitarian effort) from 2016-2024, Advisory Member since 2025; Chairman of Modern States Education Alliance (provides online

Name, Address, and Age	Position(s) Held with Registrants	Principal Occupation(s) During Past 5 Years
Kris Corbett 50	Chief Financial Officer	Chief Financial Officer and Treasurer of NMFC since 2023; Chief Financial Officer and Treasurer of New Mountain Guardian III BDC, L.L.C. (BDC) from 2023 to 2024; Chief Financial Officer and Treasurer of New Mountain Guardian IV BDC, L.L.C. (BDC) since 2023; Chief Financial Officer and Treasurer of New Mountain Guardian IV Income Fund, L.L.C. (BDC) since 2023; Chief Financial Officer and Treasurer of NMF SLF I, Inc. (BDC) since 2023; and Chief Financial Officer and Treasurer of New Mountain Private Credit Fund (BDC) since 2024.

Joseph W. Hartswell 47	Chief Compliance Officer	Managing Director and Chief Compliance Officer of New Mountain Capital, L.L.C. since 2015; Chief Compliance Officer of NMF SLF I, Inc. (BDC) since 2022; Chief Compliance Officer of New Mountain Guardian III BDC, L.L.C. (BDC) from 2022 to 2024; Chief Compliance Officer of New Mountain Guardian IV BDC, L.L.C. (BDC) since 2022; Chief Compliance Officer of New Mountain Guardian IV Income Fund, L.L.C. (BDC) since 2022; and Chief Compliance Officer of New Mountain Private Credit Fund (BDC) since 2024.

Laura C. Holson 40	Chief Operating Officer	Chief Operating Officer of NMFC since 2022; Chief Operating Officer of NMF SLF I, Inc. (BDC) since 2022; Chief Operating Officer of New Mountain Guardian III BDC, L.L.C. (BDC) from 2022 to 2024; Chief Operating Officer of New Mountain Guardian IV BDC, L.L.C. (BDC) since 2022; Chief Operating Officer of New Mountain Guardian IV Income Fund, L.L.C. (BDC) since 2022; Chief Operating Officer of New Mountain Private Credit Fund since 2024; Managing Director of New Mountain Capital, L.L.C. since 2019; Interim Chief Financial Officer from April 2023 to November 2023; Head of Capital Markets of New Mountain Capital, L.L.C. from 2017 to 2021.

Name	Fees Paid in Cash from the Company⁽¹⁾		Other Compensation from the Company		Total Compensation from the Company⁽²⁾		Fees Paid in Cash from the Fund Complex		Other Compensation Paid from the Fund Complex		Total Compensation Paid from the Fund Complex
Interested Directors
Steven B. Klinsky		—		—		—		—		—		—
Robert A. Hamwee		—		—		—		—		—		—
Adam B. Weinstein		—		—		—		—		—		—
John R. Kline		—		—		—		—		—		—
Independent Directors
David Ogens	$	141,500	$	3,543		—	$	201,229	$	7,420	$	208,649
Alfred F. Hurley, Jr.⁽³⁾	$	139,000		—		—	$	195,979		—	$	195,979
Rome G. Arnold III	$	145,500	$	1,893		—	$	184,909	$	3,387	$	188,743
Daniel B. Hébert	$	132,000		—		—	$	163,188		—	$	163,188
Barbara Daniel		134,000		—		—	$	184,354		—	$	184,354
John P. Malfettone⁽⁴⁾		—		—		—	$	62,594	$	1,790	$	64,384

	Year Ended December 31, 2025		Year Ended December 31, 2024
Audit Fees	$	933.0	$	910.0
Audit-Related Fees	$	30.0	$	275.0
Tax Fees	$	271.8	$	337.1
All Other Fees		—		—
Total Fees:	$	1,234.8	$	1,522.1

		THE AUDIT COMMITTEE

		Rome G. Arnold III, Chair Daniel B. Hébert, John P. Malfettone David Ogens Barbara Daniel


			By Order of the board of directors

			Eric Kane Corporate Secretary

SEC Form DEF 14A filed by New Mountain Finance Corporation