CoStar Group (CSGP)CEO bought ~$111K

~$111K

Approx. value · 3,100 sh @ $35.82

1.72M

Holds after · shares reported

Traded

May 1, 2026

Filed

May 4, 2026

The story around this disclosure

Every dated public record OQRO holds about the company from 60 days before to 120 days after, oldest first. It shows what was going on; none of it is a stated reason for the trade.

1. Feb 27, 2026Insider · First insider buy since Oct 2024CEO purchased ~$2.48M of CSGP shares in the open market
2. Mar 2, 2026Insider · 2 peopleInsiders: 2 purchases (~$952K)
3. Mar 6, 2026Insider · 3 insiders in a week, a first since 2006Director purchased ~$48K of CSGP shares in the open market
4. Mar 13, 2026CongressDisclosed purchase of CSGP — reported range $1,001 - $15,000
5. Mar 15, 2026Company filing · Form 8-K · Executive change, Reg FDChanged a top executive or board member, and shared information with investors“On March 15, 2026, the Board of Directors (the “Board”) of CoStar Group, Inc. (the “Company”) appointed Nana Banerjee to serve on the Board, effective immediately.”
6. Mar 26, 20265% stakeThe Vanguard Group reported a passive stake (13G)
7. Apr 14, 2026CongressDisclosed partial sale of CSGP — reported range $1,001 - $15,000
8. Apr 28, 2026Company filing · Form 8-K · Results, Reg FDReported its results, and shared information with investors
9. Apr 29, 20265% stakeVanguard Portfolio Management reported a passive stake (13G) of 9.1%
10. Apr 29, 20265% stakeVanguard Capital Management reported a passive stake (13G) of 7.5%
11. May 1, 2026 · this disclosureInsiderCEO purchased ~$111K of CSGP shares in the open market

What came next

1. May 1, 2026InsiderCEO purchased ~$2.4M of CSGP shares in the open market
2. May 28, 2026Company filing · Form 8-K · Material agreement, Reg FDSigned an important agreement, and shared information with investors
3. Jun 23, 2026Company filing · Form 8-K · Executive change, Shareholder voteChanged a top executive or board member, and held a shareholder vote (and 1 more item)“On June 23, 2026, at the Annual Meeting of Stockholders (the “Annual Meeting”) of CoStar Group, Inc. (the “Company” or “our”), the stockholders of the Company, upon the recommendation of the Board of Directors of the Company (the “Board”), approved the CoStar Group, Inc. 2026 Employee Stock Purchase Plan (the “2026 ESPP”), which was approved by the Board on April 27, 2026 and became effective upon stockholder…”
4. Jul 7, 2026Company filing · Form 8-K · Executive change, Reg FDChanged a top executive or board member, and shared information with investors“On July 13, 2026, the Board of Directors (the “Board”) of CoStar Group, Inc. (the “Company” or “CoStar Group”) appointed Robin Rossmann to serve as the Company’s Chief Financial Officer, effective July 31, 2026 (“Effective Date”).”
5. Jul 28, 2026Company filing · Form 8-K · ResultsReported its results
6. Aug 4, 2026InsiderCEO purchased ~$2.49M of CSGP shares in the open market
7. Aug 5, 2026InsiderDirector sold ~$106K of CSGP shares in the open market
8. Aug 7, 2026InsiderOfficer sold ~$147K of CSGP shares in the open market
9. Aug 14, 20265% stakeBaron Capital Group, Inc. reported a passive stake (13G) of 5.3%

How to read SEC Form 4

Form 4 is the filing that officers, directors and owners of more than 10% of a US-listed company must send to the SEC within two business days after they buy, sell or otherwise change their holding of the company's stock.

Full guide: What is an SEC Form 4?

What else is on file for CoStar Group

For CoStar Group, OQRO holds 3 insider filings (SEC Form 4 or Form 144), 1 Congress trade report and 19 fund holdings reports (13F) dated in the last 90 days.

These are records OQRO holds, counted by their date, not a measure of how much trading took place. Routine paperwork such as option exercises and tax withholding is left out. Everything for the company is on its CSGP page.

Other recent filings by Andrew C Florance, President and CEO

• SEC Form 4 at CoStar Group (CSGP)Aug 5, 2026
• SEC Form 4 at CoStar Group (CSGP)May 4, 2026
• SEC Form 4 at CoStar Group (CSGP)Mar 2, 2026
• SEC Form 4 at CoStar Group (CSGP)Oct 28, 2024

The full history of Andrew C Florance, President and CEO is on the profile page.

How this filing works

• SEC Form 4
• Open-market purchase
• Rule 10b5-1 trading plans

Other disclosures at CoStar Group

• House Clerk periodic transaction reportSep 10, 2026
• SEC Schedule 13GAug 14, 2026
• SEC Form 13F-HRAug 14, 2026
• SEC Form 13F-HRAug 14, 2026
• SEC Form 13F-HRAug 14, 2026
• SEC Form 13F-HRAug 14, 2026

Everything OQRO holds on this company is on its CSGP page.