CSGP: Leadership change · Company disclosure

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. On June 23, 2026, at the Annual Meeting of Stockholders (the “Annual Meeting”) of CoStar Group, Inc. (the “Company” or “our”), the stockholders of the Company, upon the recommendation of the Board of Directors of the Company (the “Board”), approved the CoStar Group, Inc. 2026 Employee Stock Purchase Plan (the “2026 ESPP”), which was approved by the Board on April 27, 2026 and became effective upon stockholder approval at the Annual Meeting. The 2026 ESPP replaces the Company’s Second Amended and Restated Employee Stock Purchase Plan (the “2021 ESPP”), and no further shares will be issued pursuant to the 2021 ESPP. The 2026 ESPP authorizes the issuance of 2,500,000 shares of the Company’s common stock. A more detailed description of the material terms of the 2026 ESPP was included in the Company’s Definitive Proxy Statement on Schedule 14A (the “Proxy Statement”) filed with the Securities and Exchange Commission on April 30, 2026. The foregoing and the summary in the Proxy Statement are not complete summaries of the terms of the 2026 ESPP and are qualified by reference to the text of the 2026 ESPP, which is included as Exhibit 10.1 hereto and is incorporated by reference herein. Item 5.07 Submission of Matters to a Vote of Security Holders. The following items, which are more fully described in the Proxy Statement, were submitted to a vote of the stockholders of the Company at the Annual Meeting. The final voting results are as follows: 1. Each of the following nominees was elected to our Board to serve until the Company’s 2027 Annual Meeting of Stockholders or until his or her successor is elected and qualified: Lou