Sixth Street专业贷款美股招股说明书(2026-05-11版)

5.650% Notes due 2031 We are offering $300,000,000 in aggregate principal amount of 5.650% notes due 2031, which we refer to as the Notes. The Notes will mature on August 15, 2031. We will payinterest on the Notes on February 15 and August 15 of each year, beginning on February 15, 2027. We may redeem the Notes in whole or in part at any time or from time to time at theredemption price discussed under the caption “Description of Notes—Optional Redemption” in this prospectus supplement. In addition, holders of the Notes can require us to repurchase theNotes at 100% of their principal amount upon the occurrence of a Change of Control Repurchase Event (as defined herein). The Notes will be issued in minimum denominations of $2,000and integral multiples of $1,000 in excess thereof. The Notes will be our direct, general unsecured obligations and rank pari passu, or equal, with all existing and future unsecured unsubordinated indebtedness issued by us, but willrank senior to our future indebtedness that is expressly subordinated in right of payment to the Notes. We are a specialty finance company that has elected to be regulated as a businessdevelopment company under the Investment Company Act of 1940. We seek to generate current income primarily in U.S.-domiciled middle market companies through direct originations ofsenior secured loans and, to a lesser extent, originations of mezzanine and unsecured loans and investments in corporate bonds, equity securities and other instruments. As of March31, 2026, our investment portfolio consisted of investments in 143 portfolio companies (including 36 structured credit investments, which include each series ofcollateralized loan obligation as a separate portfolio company investment) with an aggregate fair value of $3,313.4million. We intend to continue to pursue an investment strategy focusedprimarily on direct origination of loans to middle-market companies domiciled in the United States. We are an externally managed, closed-end, non-diversified management investment company. Sixth Street Specialty Lending Advisers, LLC, or the Adviser, acts as our investmentadviser and administrator. We and the Adviser are part of Sixth Street Partners, LLC, a global investment firm with over $130billion in assets under management as of March31, 2026. The companies in our investment portfolio are typically highly leveraged, and, in many cases, our investments in these companies are not rated by any rating agency. If theseinvestments were rated, we believe that most would likely receive a rating of below investment grade (that is, below BBB- or Baa3, which is often referred to as “junk”). Our exposure tobelow investment grade instruments involves certain risks, including speculation with respect to the borrower’s capacity to pay interest and repay principal. The debt investments in ourportfolio generally have a significant portion of principal due at the maturity of the investment, which would result in a substantial loss to us if such borrowers are unable to refinance or repaytheir debt at maturity. Substantially all of our debt investments have variable interest rates that reset periodically based on interest rate benchmarks such as the Euro Interbank Offered Rate, the CanadianDollar Offered Rate, the Secured Overnight Financing Rate, the Sterling Overnight Interbank Average Rate or the Prime Rate. As a result, significant increases in such interest ratebenchmarks (or any replacement benchmarks) in the future would make it more difficult for these borrowers to service their obligations under the debt investments that we hold. Investing in the Notes involves risks, including the risk of leverage, that are described in the “Risk Factors” section beginning on pageS-10 of this prospectus supplementand page24 of the accompanying prospectus and the matters discussed in the documents incorporated or deemed to be incorporated by reference in this prospectus supplementand the accompanying prospectus. Please read this prospectus supplement and the accompanying prospectus, including any information incorporated by reference herein or therein, before investing and keep suchdocuments for future reference. This prospectus supplement and the accompanying prospectus, and the documents incorporated by reference herein or therein, contain important informationabout us that a prospective investor ought to know before investing in our securities. Information required to be included in a Statement of Additional Information may be found in thisprospectus supplement and the accompanying prospectus or incorporated by reference herein or therein. We also file periodic and current reports, proxy statements and other informationabout us with the Securities and Exchange Commission (the “SEC”). This information is available free of charge by contacting us at 2100 McKinney Avenue, Suite 1500, Dallas, TX 75201,Attention: TSLX Investor Relations, by emailing us at IRTSLX@sixthstreet.com or visiting our websit