Form4insider filings, from the source

Company · CIK 0001057352 · SIC 7389 — Services-Business Services, NEC · Nasdaq

COSTAR GROUP, INC. · CSGP

Insider activity reported against this company. All insider holders · On EDGAR ↗

1M3M6M1Y2YAll datashares as filed — not split-adjusted
Open-market buys & salesbuys $2.5M · 1sales $253k · 2net $2.2M
$10k$10k$100k$100k$1M$1M$10M$10MbuyssalesSep 2024Jan 2025May 2025Sep 2025Jan 2026May 2026Sep 2026

Reported at this company — common stock

TradeReported (ET)InsiderSharesAvg priceTotalOwned afterΔ stakeFlags
Aug 7, 2026 SForm 4 →Aug 10, 4:06 pm EDTCynthia Cammett CannChief Accounting Officer4,788$30.78$147,37518,822−20.3%
Aug 5, 2026 SForm 4 →Aug 10, 4:06 pm EDTJohn W HillDirector3,500$30.21$105,73522,993−13.2% late
Aug 4, 2026 PForm 4 →Aug 5, 9:27 am EDTAndrew C FloranceFounder and CEO, Director83,300$29.89$2,489,8371,806,165+4.83%
Aug 1, 2026 FForm 4 →Aug 4, 5:24 pm EDTCynthia Cammett CannChief Accounting Officer1,077$28.76$30,97523,610—
Aug 1, 2026 FForm 4 →Aug 4, 5:24 pm EDTFrederick G. SaintPresident, Marketplaces1,436$28.76$41,299278,415—
Jul 1, 2026 FForm 4 →Jul 6, 4:05 pm EDTChristian M. LownChief Financial Officer5,597$29.36$164,328129,653—
Jun 23, 2026 AForm 4 →Jun 24, 9:14 pm EDTRachel C GlaserDirector8,262——12,419—
Jun 23, 2026 AForm 4 →Jun 24, 9:13 pm EDTJohn L BerisfordDirector8,262——11,235—
Jun 23, 2026 AForm 4 →Jun 24, 9:13 pm EDTJohn W HillDirector8,262——26,493—
Jun 23, 2026 AForm 4 →Jun 24, 9:13 pm EDTAngelique G. BrunnerDirector8,262——18,428—
Jun 23, 2026 AForm 4 →Jun 24, 9:13 pm EDTRobert W MusslewhiteDirector8,262——26,539—
Jun 23, 2026 AForm 4 →Jun 24, 9:13 pm EDTLouise S SamsDirector8,262——28,671—
Jun 23, 2026 AForm 4 →Jun 24, 9:12 pm EDTChristine M McCarthyDirector8,262——11,585—
Jun 15, 2026 FForm 4 →Jun 16, 5:32 pm EDTCynthia Cammett CannChief Accounting Officer461$32.04$14,77024,687—

Reported at this company — derivatives (options, RSUs, warrants)

TradeReported (ET)InsiderSharesAvg priceTotalOwned afterΔ stakeFlags
Jul 31, 2026 AForm 4 →Aug 4, 5:24 pm EDTRobin Jack RossmannChief Financial Officer34,771——34,771—
Jul 31, 2026 AForm 4 →Aug 4, 5:24 pm EDTCynthia Cammett CannChief Accounting Officer26,078——26,078—