v3.26.1
Investments - Summary of PSSLs Portfolio at Fair Value (Details)
$ in Thousands
 6 Months Ended 12 Months Ended
Mar. 31, 2026
USD ($)
Portfolio
Sep. 30, 2025
USD ($)
Portfolio
Schedule Of Investments [Line Items]    
Non-controlled, non-affiliated investments $ 2,580,281 [1],[2],[3],[4],[5] $ 2,773,328 [6],[7],[8],[9],[10]
PennantPark Senior Secured Loan Fund I LLC    
Schedule Of Investments [Line Items]    
Non-controlled, non-affiliated investments 1,209,044 1,084,649
PennantPark Senior Secured Loan Fund LLC Portfolio [Member]    
Schedule Of Investments [Line Items]    
Non-controlled, non-affiliated investments $ 1,209,044 $ 1,084,649
Weighted average cost yield on income producing investments 9.50% 10.10%
Number of portfolio companies in PSSL | Portfolio 120 117
Largest portfolio company investment $ 24,874 $ 20,901
Total of five largest portfolio company investments 111,858 $ 99,270
PennantPark Senior Secured Loan Fund II LLC    
Schedule Of Investments [Line Items]    
Non-controlled, non-affiliated investments $ 339,929  
Weighted average cost yield on income producing investments 8.90%  
Number of portfolio companies in PSSL | Portfolio 54  
Largest portfolio company investment $ 12,989  
Total of five largest portfolio company investments $ 64,847  
[1] All of our investments are not registered under the 1933 Act and have restrictions on resale.
[2] As of March 31, 2026, all investments were in U.S. companies and total cost, fair value, and percentage of Net Assets for the U.S companies were $2,646.4 million, $2,580.3 million, and 248.4%
[3] The provisions of the 1940 Act classify investments based on the level of control that we maintain in a particular portfolio company. As defined in the 1940 Act, a company is generally presumed to be “non-controlled” when we own 25% or less of the portfolio company’s voting securities and “controlled” when we own more than 25% of the portfolio company’s voting securities.
[4] The provisions of the 1940 Act classify investments further based on the level of ownership that we maintain in a particular portfolio company. As defined in the 1940 Act, a company is generally deemed as “non-affiliated” when we own less than 5% of a portfolio company’s voting securities and “affiliated” when we own 5% or more of a portfolio company’s voting securities.
[5] Valued based on our accounting policy (See Note 2).
[6] All of our investments are not registered under the 1933 Act and have restrictions on resale.
[7] As of September 30, 2025, all investments were in U.S companies and total cost, fair value, and percentage of Net Assets for the U.S. companies were $2,819.4 million, $2,773.3 million, and 258.1%
[8] The provisions of the 1940 Act classify investments based on the level of control that we maintain in a particular portfolio company. As defined in the 1940 Act, a company is generally presumed to be “non-controlled” when we own 25% or less of the portfolio company’s voting securities and “controlled” when we own more than 25% of the portfolio company’s voting securities.
[9] The provisions of the 1940 Act classify investments further based on the level of ownership that we maintain in a particular portfolio company. As defined in the 1940 Act, a company is generally deemed as “non-affiliated” when we own less than 5% of a portfolio company’s voting securities and “affiliated” when we own 5% or more of a portfolio company’s voting securities.
[10] Valued based on our accounting policy (See Note 2). The value of all securities was determined using significant unobservable inputs (See Note 5).