CoStar Group (CSGP) CEO adds 71,430 shares in open-market purchases

Rhea-AI Filing Summary

CoStar Group, Inc. President and CEO Andrew C. Florance reported buying additional company stock. He made two open-market purchases of the company’s common stock, totaling 71,430 shares. One trade covered 3,100 shares at $35.82 per share and the other 68,330 shares at $35.17 per share.

Insider Trade Summary

Net Buyer: 71,430 shares ($2,514,208)

Net Buy 2 txns

Insider FLORANCE ANDREW C

Role President and CEO

Bought 71,430 shs ($2.51M)

Type	Security	Shares	Price	Value
Purchase	Common Stock, par value $0.01 per share	68,330	$35.17	$2.40M
Purchase	Common Stock, par value $0.01 per share	3,100	$35.82	$111K

Holdings After Transaction: Common Stock, par value $0.01 per share — 1,719,765.03 shares (Direct, null)

Footnotes (1)

1. Average based on sales prices ranging from $34.67 to $35.67. Average based on sales prices ranging from $35.68 to $36.00.

Key Figures

Total shares purchased: 71,430 shares First trade size: 3,100 shares First trade price: $35.82 per share +2 more

5 metrics

Total shares purchased 71,430 shares Aggregate open-market purchases reported on Form 4

First trade size 3,100 shares Open-market purchase at $35.82 per share

First trade price $35.82 per share Price for 3,100-share purchase of common stock

Second trade size 68,330 shares Open-market purchase at $35.17 per share

Second trade price $35.17 per share Price for 68,330-share purchase of common stock

Key Terms

open-market purchase, Form 4, Common Stock, par value $0.01 per share, transaction code "P"

4 terms

open-market purchase financial

"transaction_action: "open-market purchase" for each transaction"

An open-market purchase is when an investor or a company buys shares on a public stock exchange at the going market price, rather than through a private deal. It matters to investors because these purchases change how many shares are available, can push the stock price up or signal confidence from large buyers, and often affect per-share metrics like earnings—think of it like someone buying lots of apples off a grocery shelf, reducing supply and potentially raising the price.

Form 4 regulatory

"INSIDER FILING DATA (Form 4)"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

Common Stock, par value $0.01 per share financial

"security_title: "Common Stock, par value $0.01 per share""

transaction code "P" regulatory

"transaction_code: "P" with description "Purchase in open market or private transaction""

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

FLORANCE ANDREW C

(Last) (First) (Middle)

C/O COSTAR GROUP, INC.

1201 WILSON BLVD.

(Street)

ARLINGTON VIRGINIA 22209

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
COSTAR GROUP, INC. [ CSGP ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President and CEO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/01/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock, par value $0.01 per share	05/01/2026		P		68,330	A	$35.17(1)	1,719,765.03	D
Common Stock, par value $0.01 per share	05/01/2026		P		3,100	A	$35.82(2)	1,722,865.03	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Average based on sales prices ranging from $34.67 to $35.67.

2. Average based on sales prices ranging from $35.68 to $36.00.

Remarks:

	/s/ Gene Boxer, Attorney-in-Fact	05/04/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What did CoStar Group (CSGP) CEO Andrew Florance report in this Form 4?

Andrew C. Florance reported buying CoStar Group common stock in the open market. He executed two separate purchases, increasing his direct ownership position in the company’s shares according to the totals disclosed in the filing.

How many CoStar Group (CSGP) shares did the CEO buy in total?

The CEO bought a total of 71,430 CoStar Group common shares. This total comes from two separate open-market purchases reported in the Form 4 insider trading disclosure for common stock with a par value of $0.01 per share.

At what prices did the CoStar Group (CSGP) CEO acquire the shares?

Andrew C. Florance bought 3,100 shares at $35.82 per share and 68,330 shares at $35.17 per share. These prices reflect the average transaction prices disclosed for each trade in the Form 4 filing.

What transaction code is used for the CoStar Group (CSGP) CEO’s trades?

Both transactions use code “P,” indicating open-market or private purchase transactions. This code confirms the trades were acquisitions of common stock rather than sales, grants, or derivative exercises under Section 16 reporting rules.

Are the CoStar Group (CSGP) CEO’s holdings direct or indirect in this filing?

The filing labels the CEO’s reported ownership as direct, using the code “D” for nature of ownership. This means the shares from these reported purchases are held directly rather than through an intermediary entity or indirect ownership structure.