 NEW YORK--BUSINESS WIRE--Sixth Street Specialty Lending, Inc. NYSE:TSLX TSLX or the Company announced today that it has launched a public offering of 4,000,000 shares of its common stock. TSLX also plans to grant the underwriters for the offering an option to purchase up to an additional 600,000 shares of its common stock. The offering will be made pursuant to a registration statement, which has been filed with, and declared effective by, the Securities and Exchange Commission the S 