CoStar Group Ownership & Insider Activity

CoStar Group (CSGP) institutional and insider ownership, recent insider transactions and ownership breakdown.

Insiders own 1.6% of shares outstanding. Institutional investors hold 76.5%.

Shares Outstanding

405.198M

Shares Float

402.258M

Insider Shares Owned

6.366M

Insider % Owned

1.6%

Institutional Shares Held

309.814M

Institutional % Held

76.5%

Ownership Breakdown

Congressional Trading Activity

Date	Member	Party	Chamber	Action	Amount
Aug 19, 2026	Gilbert Ray Cisneros	D	House	Purchase	$1,001 - $15,000
Apr 14, 2026	Gilbert Ray Cisneros	D	House	Sale (Partial)	$1,001 - $15,000
Mar 13, 2026	Gilbert Ray Cisneros	D	House	Purchase	$1,001 - $15,000
Jan 28, 2026	Gilbert Ray Cisneros	D	House	Purchase	$1,001 - $15,000
Dec 10, 2025	Gilbert Ray Cisneros	D	House	Purchase	$1,001 - $15,000
Oct 15, 2025	Gilbert Ray Cisneros	D	House	Purchase	$1,001 - $15,000
Sep 30, 2025	Gilbert Ray Cisneros	D	House	Purchase	$1,001 - $15,000
Sep 25, 2025	Lisa McClain	R	House	Sale	$1,001 - $15,000
Sep 22, 2025	Gilbert Ray Cisneros	D	House	Purchase	$1,001 - $15,000
Aug 13, 2025	Lisa McClain	R	House	Purchase	$1,001 - $15,000
Jul 31, 2025	Gilbert Ray Cisneros	D	House	Purchase	$1,001 - $15,000
Jul 9, 2025	Gilbert Ray Cisneros	D	House	Purchase	$1,001 - $15,000
Jun 30, 2025	Gilbert Ray Cisneros	D	House	Purchase	$1,001 - $15,000
Jun 27, 2025	Gilbert Ray Cisneros	D	House	Purchase	$15,001 - $50,000
Jun 25, 2025	Gilbert Ray Cisneros	D	House	Purchase	$1,001 - $15,000
May 15, 2025	Robert Bresnahan	R	House	Sale	$1,001 - $15,000
May 12, 2025	Jefferson Shreve	R	House	Sale	$15,001 - $50,000
Feb 24, 2025	Jefferson Shreve	R	House	Purchase	$15,001 - $50,000
Jan 21, 2025	William Keating	D	House	Purchase	$1,001 - $15,000
Jan 15, 2025	Julie Johnson	D	House	Sale	$1,001 - $15,000