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Costar Group, Inc.

CSGP
Exchange
Nasdaq
Industry
Services-Business Services, NEC
SEC CIK
0001057352

In the last 90 days, Costar Group, Inc. insiders filed 1 open-market purchase and 2 sales; 760 institutions reported holding it in 13F filings for Q2 2026, worth $11.7B in total; superinvestors Akre Capital Management and Weitz Investment Management hold it.

Holders of 5% or more of CSGP

Holders whose latest Schedule 13D or 13G filing reports 5% or more of Costar Group, Inc., largest stake first. The change is against the holder's previous filing.

Holders of 5% or more of CSGP
HolderLatest formStakeChangeFirst filedLatest filingFiling
BlackRock, Inc.13G/A7.50%31.8M shares–Apr 23, 20251 filingApr 23, 2025SEC

Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.

13D and 13G filings

2 Schedule 13D and 13G filings on Costar Group, Inc., newest first, including old-format filings without a stake.

Schedule 13D and 13G filings on CSGP
Filed (ET)FilerFormStakeChangeEvent dateFiling
Mar 26, 20265:42 PM ETVanguard Group Inc13G/A0.00%0 shares–Below 5%Mar 13, 2026SEC
Apr 23, 20258:39 PM ETBlackRock, Inc.13G/A7.50%31.8M shares–Mar 31, 2025SEC

Form 144: proposed insider sales

Notices from officers, directors and other affiliates planning to sell Costar Group, Inc. shares.

No Form 144 notices for Costar Group, Inc. are on file.