KBRA Affirms Ratings for Sixth Street Specialty Lending, Inc.

KBRA affirms the issuer and senior unsecured debt ratings of BBB+ for Sixth Street Specialty Lending, Inc. (NYSE: TSLX or "the company"). The Outlook is Stable.

Key Credit Considerations

The ratings reflect the company's ties to Sixth Street, a global investment firm with ~$100+ billion of assets under management, SEC exemptive relief to co-invest with Sixth Street Partners' ("Sixth Street") affiliates originating middle market loans, and a $3.4 billion diversified investment portfolio comprised largely of first lien senior secured loans (93%) with a non-cyclical focus to middle market portfolio companies. Furthermore, the company has a long track record with a solid operating history, one of the longest in the sector having been formed in 2010. As of March 31, 2025, TSLX's portfolio company weighted average EBITDA and median annual EBITDA were $111.8 million and $51.8 million, respectively. The BDC investment portfolio is focused on technology with the top three sectors being Internet Services (15.6%), Business Services (14.4%), and Human Resources and Support (10.6%). Credit quality has remained solid but non-accruals were higher than historically at 1.2% and 3.7% as a percentage of total investments at fair value and cost, respectively. The ratings are also supported by a strong management team with decades of experience in middle market lending and solid risk management practices that have resulted in high returns.

TSLX's leverage (gross) at 1.18x is appropriate given its high percentage of first lien senior secured loans, including unitranche first lien last out, and is well within the company's targeted net leverage range of 0.90x to 1.25x. Asset coverage was 185%, providing an adequate cushion to regulatory minimum of 150% in volatile and uncertain markets. The company's liquidity remains strong with $1 billion of available bank lines and $4.6 million of unrestricted cash set against $300 million senior unsecured notes maturing August 2026 and $175 million of unfunded portfolio company commitments currently eligible to be drawn. The company's unsecured debt to total debt ratio is one of the highest in the industry at 66% providing financial flexibility and low asset encumbrance for the benefit of the unsecured noteholders. TSLX has one of the longest histories of trading above NAV, and hence, has been able to raise equity. In 2024, the company raised ~$93.4 million of shares excluding its DRIP. The strengths are counterbalanced by the illiquid nature of the assets and retained earnings constraints as a Regulated Investment Company (RIC).

Formed in 2010, Sixth Street Specialty Lending, Inc. is a publicly traded closed-end externally managed non-diversified investment management company regulated as a business development company under the Investment Company Investment Act of 1940. The company has elected to be subject to tax as a RIC. The company is managed by Sixth Street Specialty Lending Advisers, LLC, an affiliate of Sixth Street Partners.

Rating Sensitivities

The ratings for TSLX are unlikely to be upgraded in the intermediate term. A rating downgrade and/or Outlook change to Negative could be considered if a prolonged downturn in the U.S. economy has a material impact on credit metrics including liquidity, leverage, and earnings. An increased focus on riskier investments or a significant change in the current management structure and/or risk management policies could also lead to negative rating action.

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