CoStar Group (NASDAQ: CSGP) insider transactions
In the twelve months to 10 November 2026, executives and directors of CoStar Group reported 4 open-market sales of 12,379 shares ($534,282) and 7 open-market purchases of 232,450 shares ($8.5m), by 6 people, according to the Form 4 filings they submitted to the SEC.
Latest transactions
| Date | Insider | Role | Transaction | Shares | Price | Held after | Filing |
|---|---|---|---|---|---|---|---|
| 15 October 2026 | Rossmann Robin Jack | Chief Financial Officer | Shares withheld for tax | −756 | $32.00 | 85,935 | Form 4 |
| 7 August 2026 | Cann Cynthia Cammett | Chief Accounting Officer | Open-market sale | −4,788 | $30.78 | 18,822 | Form 4 |
| 5 August 2026 | Hill John W | Director | Open-market sale | −3,500 | $30.21 | 22,993 | Form 4 |
| 4 August 2026 | Florance Andrew C | Founder and CEO | Open-market purchase | +83,300 | $29.89 | 1,806,165 | Form 4 |
| 1 August 2026 | Cann Cynthia Cammett | Chief Accounting Officer | Shares withheld for tax | −1,077 | $28.76 | 23,610 | Form 4 |
| 1 August 2026 | Saint Frederick G. | President, Marketplaces | Shares withheld for tax | −1,436 | $28.76 | 278,415 | Form 4 |
| 1 July 2026 | Lown Christian M. | Chief Financial Officer | Shares withheld for tax | −5,597 | $29.36 | 129,653 | Form 4 |
| 23 June 2026 | Hill John W | Director | Grant or award | +8,262 | — | 26,493 | Form 4 |
| 23 June 2026 | Musslewhite Robert W | Director | Grant or award | +8,262 | — | 26,539 | Form 4 |
| 23 June 2026 | Berisford John L | Director | Grant or award | +8,262 | — | 11,235 | Form 4 |
| 23 June 2026 | Glaser Rachel C | Director | Grant or award | +8,262 | — | 12,419 | Form 4 |
| 23 June 2026 | McCarthy Christine M | Director | Grant or award | +8,262 | — | 11,585 | Form 4 |
| 23 June 2026 | Brunner Angelique G. | Director | Grant or award | +8,262 | — | 18,428 | Form 4 |
| 23 June 2026 | Sams Louise S | Director | Grant or award | +8,262 | — | 28,671 | Form 4 |
| 15 June 2026 | Cann Cynthia Cammett | Chief Accounting Officer | Shares withheld for tax | −461 | $32.04 | 24,687 | Form 4 |
| 1 May 2026 | Florance Andrew C | President and CEO | Open-market purchase | +68,330 | $35.17 | 1,719,765 | Form 4 |
| 1 May 2026 | Florance Andrew C | President and CEO | Open-market purchase | +3,100 | $35.82 | 1,722,865 | Form 4 |
| 15 March 2026 | Cann Cynthia Cammett | Chief Accounting Officer | Shares withheld for tax | −1,194 | $43.63 | 25,148 | Form 4 |
| 15 March 2026 | Ruggles Lisa | Senior VP, Global Operations | Shares withheld for tax | −2,977 | $43.63 | 174,915 | Form 4 |
| 15 March 2026 | Boxer Gene | General Counsel and Secretary | Shares withheld for tax | −428 | $43.63 | 95,517 | Form 4 |
Names appear as in the filing, surname first. A dash in the price column means the filing reports none, as in grants and gifts.
How to read the table
Only open-market purchases and sales are trades the insider chose to make at the market price, and they are the ones counted in the summary above. Grants, option exercises and shares withheld for tax come from pay plans. A sale marked as a 10b5-1 plan was scheduled in advance under a written plan.
Where each row comes from
From the Form 4 that each executive, director or large shareholder must file with the SEC within two business days of a transaction, read up to 10 November 2026. Each row links to its filing on EDGAR. Only transactions in shares are listed, not derivatives, and amended filings are left out. The accounts of the company are on the CoStar Group page; the method, in data sources.
Information prepared from the Form 4 filings submitted to the SEC, for information purposes only. It is not financial advice or a recommendation to buy or sell. Updated on 12 November 2026.