CoStar Group Inc (CSGP) · Insider trading
What CoStar Group's directors, officers and largest holders bought and sold themselves, from the Form 4 each of them files with the SEC within two business days of a trade. Open-market purchases and sales first: those are the trades somebody chose to make at the market price.
Bought, 12 months
$8.48M
4 insiders, 7 trades
Sold, 12 months
$534,282
2 insiders, 0% under a plan
Net, 12 months
+$7.95M
bought less sold
Latest filing
2026-08-10
filings read to 2026-10-19
Who traded, two years
| Insider | Bought | Sold | Trades | Last trade | Holds after |
|---|---|---|---|---|---|
| Florance Andrew CDirector, Founder and CEO | $8.58M | – | 5 | 2026-08-04 | 1,806,165 |
| Saint Frederick G.President, Marketplaces | $906,600 | $6.62M | 4 | 2026-03-02 | 279,851 |
| Klein Michael RDirector | – | $5.35M | 1 | 2024-10-25 | 1,913,501 |
| Cann Cynthia CammettChief Accounting Officer | – | $703,200 | 5 | 2026-08-07 | 18,822 |
| Hill John WDirector | – | $470,204 | 3 | 2026-08-05 | 22,993 |
| Desmarais Michael JChief Human Resources Officer | – | $439,340 | 1 | 2024-11-26 | 58,798 |
| Nassetta Christopher JDirector | – | $135,136 | 1 | 2024-11-27 | 229,715 |
| Sams Louise SDirector | $48,360 | – | 1 | 2026-03-06 | 20,409 |
| Glaser Rachel CDirector | $44,940 | – | 1 | 2026-03-02 | 4,157 |
Open-market purchases and sales
Newest first. “Plan” marks a trade made under a 10b5-1 plan set up in advance.
| Date | Insider | Trade | Shares | Price | Value | Holds after | Filing |
|---|---|---|---|---|---|---|---|
| 2026-08-07 | Cann Cynthia CammettChief Accounting Officer | Sale | 4,788 | 30.78 | $147,375 | 18,822 | Form 4 |
| 2026-08-05 | Hill John WDirector | Sale | 3,500 | 30.21 | $105,735 | 22,993 | Form 4 |
| 2026-08-04 | Florance Andrew CDirector, Founder and CEO | Buy | 83,300 | 29.89 | $2.49M | 1,806,165 | Form 4 |
| 2026-05-01 | Florance Andrew CDirector, President and CEO | Buy | 68,330 | 35.17 | $2.40M | 1,719,765 | Form 4 |
| 2026-05-01 | Florance Andrew CDirector, President and CEO | Buy | 3,100 | 35.82 | $111,042 | 1,722,865 | Form 4 |
| 2026-03-06 | Sams Louise SDirector | Buy | 1,000 | 48.36 | $48,360 | 20,409 | Form 4 |
| 2026-03-02 | Glaser Rachel CDirector | Buy | 1,000 | 44.94 | $44,940 | 4,157 | Form 4 |
| 2026-03-02 | Saint Frederick G.President, Marketplaces | Buy | 20,000 | 45.33 | $906,600 | 279,851 | Form 4 |
| 2026-02-27 | Florance Andrew CDirector, President and CEO | Buy | 55,720 | 44.52 | $2.48M | 1,586,866 | Form 4 |
| 2025-11-13 | Cann Cynthia CammettChief Accounting Officer | Sale | 1,841 | 68.79 | $126,642 | 23,211 | Form 4 |
| 2025-11-13 | Hill John WDirector | Sale | 2,250 | 68.68 | $154,530 | 18,231 | Form 4 |
| 2025-08-28 | Saint Frederick G.President, Marketplaces | Sale | 25,000 | 90.33 | $2.26M | 293,103 | Form 4 |
| 2025-07-28 | Cann Cynthia CammettChief Accounting Officer | Sale | 2,033 | 92.85 | $188,764 | 25,771 | Form 4 |
| 2025-07-28 | Saint Frederick G.President, Marketplaces | Sale | 25,000 | 93.23 | $2.33M | 319,539 | Form 4 |
| 2025-06-11 | Saint Frederick G.President, Marketplaces | Sale | 25,000 | 81.10 | $2.03M | 344,539 | Form 4 |
| 2025-03-10 | Cann Cynthia CammettChief Accounting Officer | Sale | 1,749 | 79.90 | $139,745 | 29,456 | Form 4 |
| 2024-12-10 | Hill John WDirector | Sale | 2,735 | 76.76 | $209,939 | 17,499 | Form 4 |
| 2024-11-27 | Nassetta Christopher JDirector | Sale | 1,681 | 80.39 | $135,136 | 229,715 | Form 4 |
| 2024-11-26 | Desmarais Michael JChief Human Resources Officer | Sale | 5,500 | 79.88 | $439,340 | 58,798 | Form 4 |
| 2024-11-11 | Cann Cynthia CammettChief Accounting Officer | Sale | 1,310 | 76.85 | $100,673 | 26,485 | Form 4 |
| 2024-10-25 | Florance Andrew CDirector, President and CEO | Buy | 14,731 | 74.67 | $1.10M | 1,263,098 | Form 4 |
| 2024-10-25 | Klein Michael RDirector | Sale | 71,633 | 74.69 | $5.35M | 1,913,501 | Form 4 |
Grants, exercises and other transactions
Pay, tax and paperwork rather than a choice to trade at the market price. Two years.
50 × shares withheld for tax31 × grant or award8 × returned to the company3 × gift
Show them
| Date | Insider | What | Shares | Price | Holds after | Filing |
|---|---|---|---|---|---|---|
| 2026-08-01 | Cann Cynthia CammettChief Accounting Officer | Shares withheld for tax F | −1,077 | 28.76 | 23,610 | Form 4 |
| 2026-08-01 | Saint Frederick G.President, Marketplaces | Shares withheld for tax F | −1,436 | 28.76 | 278,415 | Form 4 |
| 2026-07-01 | Lown Christian M.Chief Financial Officer | Shares withheld for tax F | −5,597 | 29.36 | 129,653 | Form 4 |
| 2026-06-23 | Hill John WDirector | Grant or award A | +8,262 | – | 26,493 | Form 4 |
| 2026-06-23 | Musslewhite Robert WDirector | Grant or award A | +8,262 | – | 26,539 | Form 4 |
| 2026-06-23 | Berisford John LDirector | Grant or award A | +8,262 | – | 11,235 | Form 4 |
| 2026-06-23 | Glaser Rachel CDirector | Grant or award A | +8,262 | – | 12,419 | Form 4 |
| 2026-06-23 | McCarthy Christine MDirector | Grant or award A | +8,262 | – | 11,585 | Form 4 |
| 2026-06-23 | Brunner Angelique G.Director | Grant or award A | +8,262 | – | 18,428 | Form 4 |
| 2026-06-23 | Sams Louise SDirector | Grant or award A | +8,262 | – | 28,671 | Form 4 |
| 2026-06-15 | Cann Cynthia CammettChief Accounting Officer | Shares withheld for tax F | −461 | 32.04 | 24,687 | Form 4 |
| 2026-03-15 | Cann Cynthia CammettChief Accounting Officer | Shares withheld for tax F | −1,194 | 43.63 | 25,148 | Form 4 |
| 2026-03-15 | Ruggles LisaSenior VP, Global Operations | Shares withheld for tax F | −2,977 | 43.63 | 174,915 | Form 4 |
| 2026-03-15 | Boxer GeneGeneral Counsel and Secretary | Shares withheld for tax F | −482 | 43.63 | 95,463 | Form 4/A |
| 2026-03-15 | Desmarais Michael JChief Human Resources Officer | Shares withheld for tax F | −2,873 | 43.63 | 87,725 | Form 4 |
| 2026-03-15 | Simuro FrankChief Technology Officer | Shares withheld for tax F | −11,107 | 43.63 | 414,491 | Form 4 |
| 2026-03-10 | Florance Andrew CDirector, President and CEO | Grant or award A | +124,162 | – | 1,651,435 | Form 4 |
| 2026-03-10 | Cann Cynthia CammettChief Accounting Officer | Grant or award A | +4,374 | – | 26,342 | Form 4 |
| 2026-03-10 | Lown Christian M.Chief Financial Officer | Grant or award A | +12,268 | – | 135,250 | Form 4 |
| 2026-03-10 | Boxer GeneGeneral Counsel and Secretary | Grant or award A | +21,920 | – | 95,945 | Form 4 |
| 2026-03-10 | Desmarais Michael JChief Human Resources Officer | Grant or award A | +17,676 | – | 90,598 | Form 4 |
| 2026-03-01 | Florance Andrew CDirector, President and CEO | Shares withheld for tax F | −59,593 | 44.63 | 1,527,273 | Form 4 |
| 2026-03-01 | Cann Cynthia CammettChief Accounting Officer | Shares withheld for tax F | −1,385 | 44.63 | 21,968 | Form 4 |
| 2026-03-01 | Saint Frederick G.President, Marketplaces | Shares withheld for tax F | −11,096 | 44.63 | 259,851 | Form 4 |
| 2026-03-01 | Lown Christian M.Chief Financial Officer | Shares withheld for tax F | −7,175 | 44.63 | 122,982 | Form 4 |
| 2026-03-01 | Ruggles LisaSenior VP, Global Operations | Shares withheld for tax F | −8,931 | 44.63 | 177,892 | Form 4 |
| 2026-03-01 | Boxer GeneGeneral Counsel and Secretary | Shares withheld for tax F | −4,547 | 44.63 | 74,025 | Form 4 |
| 2026-03-01 | Desmarais Michael JChief Human Resources Officer | Shares withheld for tax F | −6,353 | 44.63 | 72,922 | Form 4 |
| 2026-03-01 | Simuro FrankChief Technology Officer | Shares withheld for tax F | −18,702 | 44.63 | 425,598 | Form 4 |
| 2026-02-19 | Florance Andrew CDirector, President and CEO | Returned to the company D | −104,983 | – | 1,550,367 | Form 4 |
| 2026-02-19 | Florance Andrew CDirector, President and CEO | Shares withheld for tax F | −19,221 | 49.07 | 1,531,146 | Form 4 |
| 2026-02-19 | Saint Frederick G.President, Marketplaces | Returned to the company D | −17,583 | – | 273,096 | Form 4 |
| 2026-02-19 | Saint Frederick G.President, Marketplaces | Shares withheld for tax F | −2,149 | 49.07 | 270,947 | Form 4 |
| 2026-02-19 | Ruggles LisaSenior VP, Global Operations | Returned to the company D | −17,583 | – | 190,042 | Form 4 |
| 2026-02-19 | Ruggles LisaSenior VP, Global Operations | Shares withheld for tax F | −3,219 | 49.07 | 186,823 | Form 4 |
| 2026-02-19 | Simuro FrankChief Technology Officer | Returned to the company D | −30,727 | – | 448,721 | Form 4 |
| 2026-02-19 | Simuro FrankChief Technology Officer | Shares withheld for tax F | −4,421 | 49.07 | 444,300 | Form 4 |
| 2026-02-15 | Florance Andrew CDirector, President and CEO | Shares withheld for tax F | −17,482 | 44.99 | 1,655,350 | Form 4 |
| 2026-02-15 | Saint Frederick G.President, Marketplaces | Shares withheld for tax F | −2,424 | 44.99 | 290,679 | Form 4 |
| 2026-02-15 | Ruggles LisaSenior VP, Global Operations | Shares withheld for tax F | −3,576 | 44.99 | 207,625 | Form 4 |
| 2026-02-15 | Simuro FrankChief Technology Officer | Shares withheld for tax F | −4,151 | 44.99 | 479,448 | Form 4 |
| 2025-09-09 | McCarthy Christine MDirector | Grant or award A | +2,973 | – | 2,973 | Form 4 |
| 2025-09-09 | Hill John WDirector | Grant or award A | +3,177 | – | 20,481 | Form 4 |
| 2025-09-09 | Musslewhite Robert WDirector | Grant or award A | +3,121 | – | 18,277 | Form 4 |
| 2025-09-09 | Berisford John LDirector | Grant or award A | +2,973 | – | 2,973 | Form 4 |
| 2025-09-09 | Glaser Rachel CDirector | Grant or award A | +3,143 | – | 3,143 | Form 4 |
| 2025-09-09 | Brunner Angelique G.Director | Grant or award A | +3,143 | – | 10,166 | Form 4 |
| 2025-09-09 | Sams Louise SDirector | Grant or award A | +3,291 | – | 19,409 | Form 4 |
| 2025-08-01 | Cann Cynthia CammettChief Accounting Officer | Shares withheld for tax F | −719 | 95.19 | 25,052 | Form 4 |
| 2025-08-01 | Saint Frederick G.President, Marketplaces | Shares withheld for tax F | −1,436 | 95.19 | 318,103 | Form 4 |
| 2025-07-01 | Lown Christian M.Chief Financial Officer | Shares withheld for tax F | −4,666 | 80.40 | 130,157 | Form 4 |
| 2025-06-15 | Cann Cynthia CammettChief Accounting Officer | Shares withheld for tax F | −461 | 81.16 | 27,804 | Form 4 |
| 2025-06-01 | Ruggles LisaSenior VP, Global Operations | Shares withheld for tax F | −12 | 73.56 | 211,201 | Form 4 |
| 2025-03-15 | Simuro FrankChief Technology Officer | Shares withheld for tax F | −5,700 | 78.73 | 483,599 | Form 4 |
| 2025-03-15 | Desmarais Michael JChief Human Resources Officer | Shares withheld for tax F | −3,641 | 78.73 | 79,118 | Form 4 |
| 2025-03-15 | Boxer GeneGeneral Counsel and Secretary | Shares withheld for tax F | −481 | 78.73 | 78,572 | Form 4 |
| 2025-03-15 | Cann Cynthia CammettChief Accounting Officer | Shares withheld for tax F | −1,191 | 78.73 | 28,265 | Form 4 |
| 2025-03-15 | Ruggles LisaSenior VP, Global Operations | Shares withheld for tax F | −1,958 | 78.73 | 211,213 | Form 4 |
| 2025-03-05 | Desmarais Michael JChief Human Resources Officer | Grant or award A | +9,026 | – | 82,759 | Form 4 |
| 2025-03-05 | Florance Andrew CDirector, President and CEO | Grant or award A | +76,232 | – | 1,672,832 | Form 4 |
| 2025-03-05 | Boxer GeneGeneral Counsel and Secretary | Grant or award A | +12,492 | – | 79,053 | Form 4 |
| 2025-03-05 | Cann Cynthia CammettChief Accounting Officer | Grant or award A | +1,498 | – | 33,715 | Form 4 |
| 2025-03-01 | Simuro FrankChief Technology Officer | Shares withheld for tax F | −12,432 | 76.25 | 489,299 | Form 4 |
| 2025-03-01 | Florance Andrew CDirector, President and CEO | Shares withheld for tax F | −41,296 | 76.25 | 1,596,600 | Form 4 |
| 2025-03-01 | Boxer GeneGeneral Counsel and Secretary | Shares withheld for tax F | −3,644 | 76.25 | 66,561 | Form 4 |
| 2025-03-01 | Cann Cynthia CammettChief Accounting Officer | Shares withheld for tax F | −813 | 76.25 | 32,217 | Form 4 |
| 2025-03-01 | Saint Frederick G.President, Marketplaces | Shares withheld for tax F | −8,252 | 76.25 | 369,539 | Form 4 |
| 2025-03-01 | Desmarais Michael JChief Human Resources Officer | Shares withheld for tax F | −3,893 | 76.25 | 73,733 | Form 4 |
| 2025-03-01 | Ruggles LisaSenior VP, Global Operations | Shares withheld for tax F | −7,410 | 76.25 | 213,171 | Form 4 |
| 2025-02-27 | Boxer GeneGeneral Counsel and Secretary | Grant or award A | +26,897 | – | 70,205 | Form 4 |
| 2025-02-27 | Cann Cynthia CammettChief Accounting Officer | Grant or award A | +4,035 | – | 33,030 | Form 4 |
| 2025-02-27 | Desmarais Michael JChief Human Resources Officer | Grant or award A | +18,828 | – | 77,626 | Form 4 |
| 2025-02-20 | Saint Frederick G.President, Marketplaces | Grant or award A | +97,600 | – | 377,791 | Form 4 |
| 2025-02-20 | Simuro FrankChief Technology Officer | Grant or award A | +130,640 | – | 501,731 | Form 4 |
| 2025-02-20 | Ruggles LisaSenior VP, Global Operations | Grant or award A | +65,440 | – | 220,581 | Form 4 |
| 2025-02-20 | Florance Andrew CDirector, President and CEO | Grant or award A | +451,440 | – | 1,637,896 | Form 4 |
| 2025-02-20 | Lown Christian M.Chief Financial Officer | Grant or award A | +97,600 | – | 134,823 | Form 4 |
| 2025-02-15 | Saint Frederick G.President, Marketplaces | Shares withheld for tax F | −2,349 | 74.06 | 293,245 | Form 4 |
| 2025-02-15 | Florance Andrew CDirector, President and CEO | Shares withheld for tax F | −14,235 | 74.06 | 1,248,863 | Form 4 |
| 2025-02-15 | Ruggles LisaSenior VP, Global Operations | Shares withheld for tax F | −3,531 | 74.06 | 169,074 | Form 4 |
| 2025-02-15 | Simuro FrankChief Technology Officer | Shares withheld for tax F | −5,485 | 74.06 | 385,019 | Form 4 |
| 2025-02-13 | Saint Frederick G.President, Marketplaces | Returned to the company D | −6,452 | – | 286,793 | Form 4 |
| 2025-02-13 | Saint Frederick G.President, Marketplaces | Shares withheld for tax F | −6,602 | 73.27 | 280,191 | Form 4 |
| 2025-02-13 | Simuro FrankChief Technology Officer | Returned to the company D | −6,452 | – | 378,567 | Form 4 |
| 2025-02-13 | Simuro FrankChief Technology Officer | Shares withheld for tax F | −7,476 | 73.27 | 371,091 | Form 4 |
| 2025-02-13 | Ruggles LisaSenior VP, Global Operations | Returned to the company D | −6,452 | – | 162,622 | Form 4 |
| 2025-02-13 | Ruggles LisaSenior VP, Global Operations | Shares withheld for tax F | −7,481 | 73.27 | 155,141 | Form 4 |
| 2025-02-13 | Florance Andrew CDirector, President and CEO | Returned to the company D | −28,896 | – | 1,219,967 | Form 4 |
| 2025-02-13 | Florance Andrew CDirector, President and CEO | Shares withheld for tax F | −33,511 | 73.27 | 1,186,456 | Form 4 |
| 2024-12-10 | Klein Michael RDirector | Gift G | −64,909 | – | 1,848,592 | Form 4 |
| 2024-12-10 | Hill John WDirector | Gift G | −195 | – | 17,304 | Form 4 |
| 2024-10-25 | Klein Michael RDirector | Gift G | −5,872 | – | 1,985,134 | Form 4 |
How to read it
- Buy, sale
- Code P and S on the form: shares bought or sold in the market, at the market price. The other codes are mostly pay (a grant, an option exercised) or tax (shares the company withheld), and say little about what the insider thinks of the price.
- Plan
- A sale or purchase under a Rule 10b5-1 plan, set up in advance and running on its own schedule. Since April 2023 the form has a box for it. Much executive selling is planned and says more about diversifying than about the company.
- Holds after
- The shares the insider still held after the trade, in the form the trade was in (directly, or indirectly through a trust or a fund).
- Value
- Shares times the price the form reports, which is often an average over several fills on the day.
Read from the SEC's own quarterly data sets of Forms 3, 4 and 5, and from each day's filings since the last one. A correcting amendment replaces the lines it restates. Every row links to its filing. None of this is advice: insiders sell for many reasons, and buy for fewer.