Costar's three largest insider shareholders as of June 02, 2026 are Michael R Klein (Director, 1.85Mn shares), Andrew C Florance (President And Ceo, 1.65Mn shares), Frank Simuro (Chief Technology Officer, 414.49K shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| Andrew C Florance | President And Ceo | 1,651,435 | 0 | 11 Mar, 2026 |
| Michael R Klein | - | 1,848,592 | 0 | 11 Dec, 2024 |
| Christopher J Nassetta | - | 229,715 | 0 | 02 Dec, 2024 |
| Christine M Mccarthy | - | 2,973 | 0 | 11 Sep, 2025 |
| John W Hill | - | 18,231 | 0 | 17 Nov, 2025 |
| Robert W Musslewhite | - | 18,277 | 0 | 11 Sep, 2025 |
| John L Berisford | - | 2,973 | 0 | 11 Sep, 2025 |
| Frederick G. Saint | President, Marketplaces | 279,851 | 0 | 03 Mar, 2026 |
| Scott T Wheeler | Chief Financial Officer | 303,417 | 0 | 30 Apr, 2024 |
| Laura Cox Kaplan | - | 17,835 | 0 | 05 Aug, 2024 |
| Lisa Ruggles | Senior Vp, Global Operations | 174,915 | 0 | 17 Mar, 2026 |
| Angelique G. Brunner | - | 10,166 | 0 | 11 Sep, 2025 |
| Gene Boxer | General Counsel And Secretary | 95,517 | 0 | 17 Mar, 2026 |
| Louise S Sams | - | 20,409 | 0 | 09 Mar, 2026 |
| Michael J Desmarais | Chief Human Resources Officer | 87,725 | 0 | 17 Mar, 2026 |
| Frank Simuro | Chief Technology Officer | 414,491 | 0 | 17 Mar, 2026 |
* Please note that the shares above only reflect shares from the fund portfolio and the institutional portfolio. Shares from the personal portfolio are excluded from this Institutional Ownership Page. See these insiders' latest transactions here on Insider Page.
| Transaction Date | Insider Name | Security Class | Transaction Type | Shares Traded | Price | Shares Remaining | Ownership | Code |
|---|---|---|---|---|---|---|---|---|
| 15 Mar, 2026 | Gene Boxer | Common Stock, par value $0.01 per share | D | 482 | $43.63 | 95,463 | D | F |
| 15 Mar, 2026 | Michael J Desmarais | Common Stock, par value $0.01 per share | D | 2,873 | $43.63 | 87,725 | D | F |
| 15 Mar, 2026 | Lisa Ruggles | Common Stock, par value $0.01 per share | D | 2,977 | $43.63 | 174,915 | D | F |
| 15 Mar, 2026 | Gene Boxer | Common Stock, par value $0.01 per share | D | 428 | $43.63 | 95,517 | D | F |
| 15 Mar, 2026 | Lisa Ruggles | Common Stock, par value $0.01 per share | D | 2,977 | $43.63 | 174,915 | D | F |
| 15 Mar, 2026 | Frank Simuro | Common Stock, par value $0.01 per share | D | 11,107 | $43.63 | 414,491 | D | F |
| 15 Mar, 2026 | Frank Simuro | Common Stock, par value $0.01 per share | D | 11,107 | $43.63 | 414,491 | D | F |
| 15 Mar, 2026 | Michael J Desmarais | Common Stock, par value $0.01 per share | D | 2,873 | $43.63 | 87,725 | D | F |
| 10 Mar, 2026 | Andrew C Florance | Common Stock, par value $0.01 per share | A | 124,162 | - | 1,651,435 | D | A |
| 10 Mar, 2026 | Michael J Desmarais | Common Stock, par value $0.01 per share | A | 17,676 | - | 90,598 | D | A |
| 10 Mar, 2026 | Michael J Desmarais | Common Stock, par value $0.01 per share | A | 17,676 | - | 90,598 | D | A |
| 10 Mar, 2026 | Gene Boxer | Common Stock, par value $0.01 per share | A | 21,920 | - | 95,945 | D | A |
| 06 Mar, 2026 | Louise S Sams | Common Stock, par value $0.01 per share | A | 1,000 | $48.36 | 20,409 | D | P |
| 06 Mar, 2026 | Louise S Sams | Common Stock, par value $0.01 per share | A | 1,000 | $48.36 | 20,409 | D | P |
| 27 Feb, 2026 | Frederick G. Saint | Restricted Stock Units | A | 39,652 | $0.00 | 39,652 | D | A |
| 01 Mar, 2026 | Andrew C Florance | Common Stock, par value $0.01 per share | D | 59,593 | $44.63 | 1,527,273 | D | F |
| 01 Mar, 2026 | Lisa Ruggles | Common Stock, par value $0.01 per share | D | 8,931 | $44.63 | 177,892 | D | F |
| 01 Mar, 2026 | Frank Simuro | Common Stock, par value $0.01 per share | D | 18,702 | $44.63 | 425,598 | D | F |
| 01 Mar, 2026 | Frederick G. Saint | Common Stock, par value $0.01 per share | D | 11,096 | $44.63 | 259,851 | D | F |
| 01 Mar, 2026 | Frederick G. Saint | Common Stock, par value $0.01 per share | D | 11,096 | $44.63 | 259,851 | D | F |