Question 1

Who are the insiders buying COSTAR GROUP, INC. stock?

Accepted Answer

InsiderAct tracks all open-market purchases of COSTAR GROUP, INC. stock by corporate insiders — including officers, directors, and shareholders owning more than 10% — sourced from public SEC Form 4 filings.

Question 2

What does insider buying at a company mean?

Accepted Answer

When a corporate officer, director, or major shareholder purchases their own company's stock on the open market using personal funds, it signals confidence in the company's outlook. This is especially meaningful when multiple insiders buy within the same 7–14 day window (cluster buying) or when the purchase size exceeds $100,000.

Question 3

How do I find cluster buying signals for a company?

Accepted Answer

InsiderAct automatically detects cluster buying — two or more insiders independently purchasing shares within a 14-day window. When a cluster buy signal is active for a company, it appears prominently on the company's InsiderAct page and on the Signals tab.

Question 4

Has COSTAR GROUP, INC. had any recent large insider purchases?

Accepted Answer

InsiderAct tracks all open-market purchases of $100,000 or more at COSTAR GROUP, INC.. Large insider purchases are flagged as high-conviction signals because they represent meaningful personal capital commitments by executives or directors who have direct visibility into the company's operations and prospects.

Question 5

Where do the insider transactions on this page come from?

Accepted Answer

All transactions shown on InsiderAct company pages are sourced directly from SEC EDGAR Form 4 filings — the mandatory public disclosures that corporate insiders must submit within 2 business days of any stock transaction. InsiderAct ingests these filings in near real time and filters for open-market purchases and sales.


2026-10-16	2026-10-15	Rossmann Robin Jack	CFO	Tax Payment	756	$32.00	$24,192
2026-08-10	2026-08-07	Cann Cynthia Cammett	CAO	Sale	4,788	$30.78	$147,375
2026-08-10	2026-08-05	Hill John W	Director	Sale	3,500	$30.21	$105,735
2026-08-05	2026-08-04	Florance Andrew C	CEO	Purchase	83,300	$29.89	$2,489,837
2026-08-04	2026-08-01	Cann Cynthia Cammett	CAO	Tax Payment	1,077	$28.76	$30,975
2026-08-04	2026-08-01	Saint Frederick G.	President	Tax Payment	1,436	$28.76	$41,299
2026-07-06	2026-07-01	Lown Christian M.	CFO	Tax Payment	5,597	$29.36	$164,328
2026-06-25	2026-06-23	Hill John W	Director	Award	8,262	$0.00	$0
2026-06-25	2026-06-23	Musslewhite Robert W	Director	Award	8,262	$0.00	$0
2026-06-25	2026-06-23	Mccarthy Christine M	Director	Award	8,262	$0.00	$0

CSGP

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