CSGP: Financial results

Item 2.02 Results of Operations and Financial Condition. On July 28, 2026 , CoStar Group, Inc. (“CoStar Group” or the “Company”) announced its financial and operating results for the quarter ended June 30, 2026. The full text of the press release (the “Press Release”) issued in connection with the announcement is furnished as Exhibit 99.1 to this Current Report on Form 8-K. The information contained in this Item 2.02 and the Press Release shall be considered “furnished” and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended, nor shall it be deemed incorporated by reference into any reports or filings with the Securities and Exchange Commission (the "SEC"), whether made before or after the date hereof, except as expressly set forth by specific reference in such a filing. Item 9.01 Financial Statements and Exhibits. Exhibit No. Description 99.1 CoStar Group, Inc. Press Release dated July 28, 2026 104 Cover Page Interactive Data File (formatted as inline XBRL and contained in Exhibit 101). SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. COSTAR GROUP, INC. By: /s/ Christian M. Lown Date: July 28, 2026 Name: Christian M. Lown Title: Chief Financial Officer