Form 4 Filing for SIMURO FRANK - COSTAR GROUP, INC.

Frank Simuro, Chief Technology Officer of COSTAR GROUP, INC. (CSGP), reported a disposition of 11,107 shares of common stock on March 15, 2026. The shares were sold at a price of $43.63 per share, with the transaction code 'F' indicating a sale. Following this transaction, Mr. Simuro owns 414,491 shares of the company's common stock. The closing price of the stock on the preceding business day, March 13, 2026, was also $43.63, as noted in footnote F1. This filing, document type 4, was signed on March 17, 2026, by an attorney-in-fact.