The Company’s investment objective is to generate current income and, to a lesser extent, capital appreciation primarily through direct originations of secured debt, including first lien, unitranche debt, including last out portions of such loans, and second lien debt, and unsecured debt, including mezzanine debt, as well as through select equity investments.

Risk Factors [Table Text Block]

ITEM 1A. RISK FACTORS

An investment in our securities involves a high degree of risk. There have been no material changes to the risk factors previously reported under Item 1A. “Risk Factors” of our annual report on Form 10-K for the year ended December 31, 2025, which was filed with the SEC on March 3, 2026. Additional risks and uncertainties not currently known to us or that we currently deem to be immaterial may materially affect our business, financial condition and/or operating results.

NAV Per Share

^[1]

$ 20.16

$ 19.83

$ 20.26

$ 19.84

Capital Stock, Long-Term Debt, and Other Securities [Abstract]

Long Term Debt, Title [Text Block]

Credit Facility

Phillip Street Middle Market Lending Investments LLC (“SPV”), an indirectly wholly-owned subsidiary of the Company, entered into the Credit Facility on February 10, 2023 with Ally Bank (“Ally”) as administrative agent and collateral agent. State Street Bank and Trust Company serves as collateral custodian and securities intermediary. We serve as collateral manager under the Credit Facility.

The Credit Facility is drawable in U.S. dollars. As of March 31, 2026, the total commitments under the Credit Facility were $750 million. The Credit Facility also has an accordion feature, subject to the satisfaction of various conditions, which could bring total commitments under the Credit Facility to $1 billion. Proceeds from borrowings under the Credit Facility may be used to acquire portfolio loans, fund unfunded commitments with respect to loans, make distributions or pay related expenses. All amounts outstanding under the Credit Facility must be repaid by December 20, 2029.

Advances under the Credit Facility bear interest (at our election) at a per annum rate equal to either (x) Daily Simple SOFR (as defined in the Credit Facility) or (y) Term SOFR (as defined in the Credit Facility) with an Available Tenor (as defined in the Credit Facility) of either one month or three months. The applicable spread is 1.85% per annum. We paid a non-usage fee of 0.50% per annum for the first three months on the average daily unused amount of the financing commitments. Thereafter, we pay between 0.50% and 1.00% per annum, depending on the unused amount of the financing commitments, on the average daily unused amount of the financing commitments. On September 26, 2024, SPV entered into a second amendment to the Credit Facility (the "Second Amendment"). The Second Amendment, among other things, amended certain components of the Borrowing Base (as defined in the Credit Facility), resulting in an increase in the Borrowing Base. On December 20, 2024, SPV entered into a third amendment to the Credit Facility (the "Third Amendment"). The Third Amendment, among other things, extended the maturity date, decreased the applicable spread, increased the total commitments under the Credit Facility, and increased the accordion feature and amended certain components of the Borrowing Base (as defined in the Credit Facility), resulting in an increase in the Borrowing Base. On October 28, 2025, SPV entered into a fourth amendment (the “Fourth Amendment”) to the Credit Facility. The Fourth Amendment, among other things, decreased the Facility Amount (as defined in the Credit Facility) to $480.00 million, decreased the applicable spread, amended certain components of the Borrowing Base (as defined in the Credit Agreement), resulting in an increase to the Borrowing Base and adds the ability to borrow under a swingline sub-facility that is available on a same day basis. On January 16, 2026, SPV entered into a fifth amendment (the “Fifth Amendment”) to the Credit Facility. The Fifth Amendment, among other things, increased the Facility Amount to $750.00 million and amended certain components of the Borrowing Base (as defined in the Credit Facility), resulting in an increase to the Borrowing Base. On March 27, 2026, SPV entered into a sixth amendment (the “Sixth Amendment”) to the Credit Facility. The Sixth Amendment removed the spread adjustment applicable to advances bearing interest based on Term SOFR (as defined in the Credit Facility).

For further details, see Note 6 “Debt―Credit Facility” to our consolidated financial statements included in this report.

Long Term Debt, Structuring [Text Block]

All amounts outstanding under the Credit Facility must be repaid by December 20, 2029.

[1]	The per Unit data was derived by using the weighted average Units outstanding during the applicable period, except for distributions recorded, which reflects the actual amount of distribution recorded per Unit for the applicable period.