v3.26.1
Investments - Investment Cost and Fair Value by Type and by Industry (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Schedule of Investments [Line Items]    
Cost $ 2,464,428 [1] $ 2,912,115 [2]
Fair Value 2,289,805 [1] 2,742,013 [2]
Business Services    
Schedule of Investments [Line Items]    
Cost 515,611 573,549
Fair Value 473,876 516,701
Software    
Schedule of Investments [Line Items]    
Cost 405,761 533,638
Fair Value 378,288 526,440
Healthcare    
Schedule of Investments [Line Items]    
Cost 398,944 517,598
Fair Value 368,847 463,591
Investment Funds (includes investments in joint ventures)    
Schedule of Investments [Line Items]    
Cost 275,632 275,632
Fair Value 266,595 275,677
Consumer Services    
Schedule of Investments [Line Items]    
Cost 144,795 193,415
Fair Value 139,986 192,842
Financial Services & Technology    
Schedule of Investments [Line Items]    
Cost 128,804 165,745
Fair Value 132,238 172,215
Net Lease    
Schedule of Investments [Line Items]    
Cost 83,623 81,370
Fair Value 121,408 115,127
Education    
Schedule of Investments [Line Items]    
Cost 199,121 195,960
Fair Value 118,313 118,507
Distribution & Logistics    
Schedule of Investments [Line Items]    
Cost 109,253 162,382
Fair Value 99,060 158,599
Packaging    
Schedule of Investments [Line Items]    
Cost 88,305 76,052
Fair Value 89,056 75,324
Energy    
Schedule of Investments [Line Items]    
Cost 78,754 75,771
Fair Value 67,816 65,833
Food & Beverage    
Schedule of Investments [Line Items]    
Cost 21,100 21,193
Fair Value 21,250 21,177
Consumer Products    
Schedule of Investments [Line Items]    
Cost 14,725 14,283
Fair Value 13,072 14,283
Business Products    
Schedule of Investments [Line Items]    
Cost   15,897
Fair Value   16,026
Specialty Chemicals & Materials    
Schedule of Investments [Line Items]    
Cost   9,630
Fair Value   9,671
First lien    
Schedule of Investments [Line Items]    
Cost 1,510,307 1,854,022
Fair Value 1,453,636 1,818,215
Second lien    
Schedule of Investments [Line Items]    
Cost 88,279 104,890
Fair Value 74,299 91,179
Subordinated    
Schedule of Investments [Line Items]    
Cost 98,129 128,705
Fair Value 98,429 121,487
Structured Finance Obligations    
Schedule of Investments [Line Items]    
Cost 3,232 3,232
Fair Value 3,191 3,277
Equity and other    
Schedule of Investments [Line Items]    
Cost 764,481 821,266
Fair Value $ 660,250 $ 707,855
[1] New Mountain Finance Corporation (the "Company") generally acquires its investments in private transactions exempt from registration under the Securities Act of 1933, as amended (the "Securities Act"). These investments are generally subject to certain limitations on resale, and may be deemed to be "restricted securities" under the Securities Act.
[2] New Mountain Finance Corporation (the "Company") generally acquires its investments in private transactions exempt from registration under the Securities Act of 1933, as amended (the "Securities Act"). These investments are generally subject to certain limitations on resale, and may be deemed to be "restricted securities" under the Securities Act.