Exhibit (n)(4)

Deloitte & Touche LLP 30 Rockefeller Plaza
New York, NY 10112-0015
USA Tel:  +1 212 492 4000
Fax: +1 212 489 1687
www.deloitte.com

June 4, 2019

The Board of Directors of

New Mountain Finance Corporation

New York, New York

We have reviewed, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the unaudited interim financial information of New Mountain Finance Corporation and subsidiaries for the three-month periods ended March 31, 2019 and 2018, and have issued our report dated May 6, 2019. As indicated in such report, because we did not perform an audit, we expressed no opinion on that information.

We are aware that our report referred to above, which was included in your Quarterly Report on Form 10-Q for the quarter ended March 31, 2019 is being used in this Post-Effective Amendment No. 1 to the Registration Statement No. 333-230326 on Form N-2.

We also are aware that the aforementioned report, pursuant to Rule 436(c) under the Securities Act of 1933, is not considered a part of the Registration Statement prepared or certified by an accountant or a report prepared or certified by an accountant within the meaning of Sections 7 and 11 of that Act.

/s/ DELOITTE & TOUCHE LLP