CoStar Group, Inc. (CSGP)
Nasdaq: CSGP · Services-Business Services, NEC · Arlington, VA · filing with the SEC since 1998
Grade6.1
◀ Past 6.8● Present 5.5▶ Future 6.1
Who owns CoStar Group, Inc.
As filed with the SECHolders of 5% or more
4
Vanguard Portfolio Management holds 9.12% of Common Stock, as its SCHEDULE 13G filed Apr 29, 2026 says.
Directors and officers
18
report now, of 27 people on the record since 2006. Their holdings as a group are not read here.
Institutions as a whole
n/a
The record does not read the share held by managers that file Form 13F, so none is printed and no split of the rest is estimated. What it holds is the 4 named at left.
Holders of 5% or moreshare of the class, as filed
Vanguard Portfolio Management
SCHEDULE 13G · filed Apr 29, 2026 · Common Stock
Vanguard Capital Management
SCHEDULE 13G · filed Apr 29, 2026 · Common Stock
Blackrock, Inc.
SCHEDULE 13G/A · filed Apr 23, 2025 · Common Stock
Baron Capital Group, Inc.
SCHEDULE 13G · filed Aug 14, 2026 · Common Stock ($0.01 par value)
The Vanguard Group
SCHEDULE 13G/A · filed Mar 26, 2026 · Common Stock · reported falling below 5%
What CSGP reports owning in othersstakes of 5% or more, and other ties
Other ties the annual report names
Matterport
A company bought · acquisition · Feb 2025 · owns, named in the 10-K filed Feb 26, 2026
Visual Lease
A company bought · acquisition · Oct 2024 · owns, named in the 10-K filed Feb 26, 2026
On the Market
A company bought · acquisition · Nov 2023 · owns, named in the 10-K filed Feb 26, 2026
Arlington Office Tower
A company bought · asset acquisition · owns, named in the 10-K filed Feb 26, 2026
92 subsidiaries in 16 countries, from the list filed with the 10-K filed Feb 26, 2026.
Insider tradesForm 4
4sales
7purchases
0sales on a scheduled plan
2people selling
$500,000sold, in dollars
$8.5Mbought, in dollars
Open-market trades on Form 4 from Nov 10, 2025 to Nov 10, 2026. A scheduled plan is a selling program set in advance under SEC rule 10b5-1. The trades are listed as filed and do not feed the grade.
By calendar yearSoldBought
2026 runs to Nov 10, 2026. Dollars as filed, summed by the transaction date.
People who traded in the window6 of 27 on the roster
| Person | Role as filed | Sales | Sold | On a plan | Buys | Bought |
|---|---|---|---|---|---|---|
| Cann Cynthia Cammett | Chief Accounting Officer | 2 | $300,000 | 0 | 0 | $0 |
| Hill John W | director | 2 | $300,000 | 0 | 0 | $0 |
| Florance Andrew C | Founder and CEO | 0 | $0 | 0 | 4 | $7.5M |
| Saint Frederick G. | President, Marketplaces | 0 | $0 | 0 | 1 | $900,000 |
| Glaser Rachel C | director | 0 | $0 | 0 | 1 | $0 |
| Sams Louise S | director | 0 | $0 | 0 | 1 | $0 |