As of March 23, 2026, Costar's top three insider holders are Michael R Klein (Director, 1.85Mn shares), Andrew C Florance (President And Ceo, 1.65Mn shares), Frank Simuro (Chief Technology Officer, 425.60K shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| Michael R Klein | 1,848,592 | 0 | 11 Dec, 2024 | |
| Andrew C Florance | President And Ceo | 1,651,435 | 0 | 11 Mar, 2026 |
| Frank Simuro | Chief Technology Officer | 414,491 | 0 | 17 Mar, 2026 |
| Scott T Wheeler | Chief Financial Officer | 303,417 | 0 | 30 Apr, 2024 |
| Frederick G. Saint | President, Marketplaces | 279,851 | 0 | 03 Mar, 2026 |
| Christopher J Nassetta | 229,715 | 0 | 02 Dec, 2024 | |
| Lisa Ruggles | Senior Vp, Global Operations | 174,915 | 0 | 17 Mar, 2026 |
| Christian M. Lown | Chief Financial Officer | 135,250 | 0 | 11 Mar, 2026 |
| Michael J Glosserman | 101,465 | 0 | 01 Nov, 2023 | |
| Gene Boxer | General Counsel And Secretary | 95,517 | 0 | 17 Mar, 2026 |
| Michael J Desmarais | Chief Human Resources Officer | 87,725 | 0 | 17 Mar, 2026 |
| Christopher J Nassetta | 0 | 46,000 | 09 May, 2024 | |
| Cynthia Cammett Cann | Chief Accounting Officer | 25,148 | 0 | 17 Mar, 2026 |
| Louise S Sams | 20,409 | 0 | 09 Mar, 2026 | |
| Robert W Musslewhite | 18,277 | 0 | 11 Sep, 2025 | |
| John W Hill | 18,231 | 0 | 17 Nov, 2025 | |
| Laura Cox Kaplan | 17,835 | 0 | 05 Aug, 2024 | |
| Rachel C Glaser | 4,157 | 0 | 03 Mar, 2026 | |
| Christine M Mccarthy | 2,973 | 0 | 11 Sep, 2025 | |
| Scott T Wheeler | Chief Financial Officer | 0 | 1,541 | 14 Mar, 2024 |
* 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 | Cynthia Cammett Cann | Common Stock, par value $0.01 per share | D | 1,194 | $43.63 | 25,148 | 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 | Frank Simuro | Common Stock, par value $0.01 per share | D | 11,107 | $43.63 | 414,491 | D | F |
| 15 Mar, 2026 | Gene Boxer | Common Stock, par value $0.01 per share | D | 482 | $43.63 | 95,463 | 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 |
| 10 Mar, 2026 | Gene Boxer | Common Stock, par value $0.01 per share | A | 21,920 | - | 95,945 | D | A |
| 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 | Cynthia Cammett Cann | Common Stock, par value $0.01 per share | A | 4,374 | - | 26,342 | 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 | Christian M. Lown | Common Stock, par value $0.01 per share | A | 12,268 | - | 135,250 | 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 |
| 27 Feb, 2026 | Frederick G. Saint | Restricted Stock Units | A | 39,652 | $0.00 | 39,652 | D | A |
| 01 Mar, 2026 | Christian M. Lown | Common Stock, par value $0.01 per share | D | 7,175 | $44.63 | 122,982 | D | F |
| 01 Mar, 2026 | Cynthia Cammett Cann | Common Stock, par value $0.01 per share | D | 1,385 | $44.63 | 21,968 | D | F |
| 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 | Gene Boxer | Common Stock, par value $0.01 per share | D | 4,547 | $44.63 | 74,025 | 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 | Michael J Desmarais | Common Stock, par value $0.01 per share | D | 6,353 | $44.63 | 72,922 | 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 |