[Form 4] COSTAR GROUP, INC. Insider Trading Activity

Rhea-AI Filing Summary

CoStar Group, Inc. reported an insider stock sale by its Chief Accounting Officer. On 11/13/2025, the officer sold 1,841 shares of CoStar Group common stock at an average price of $68.79 per share. The filing notes this average is based on sales prices ranging from $68.78 to $68.85. After this transaction, the officer directly beneficially owned 23,211 shares of CoStar Group common stock.

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

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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^*

Cann Cynthia Cammett

(Last) (First) (Middle)

C/O COSTAR GROUP, INC.

1201 WILSON BLVD.

(Street)

ARLINGTON VA 22209

(City) (State) (Zip)

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

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Accounting Officer

3. Date of Earliest Transaction (Month/Day/Year)
11/13/2025

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

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

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

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	11/13/2025		S		1,841	D	$68.79(1)	23,211	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 $68.78 to $68.85.

Remarks:

	/s/ Gene Boxer, Attorney-in-Fact	11/17/2025
	** 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.

FAQ

What insider transaction did CoStar Group (CSGP) report in this Form 4?

The filing reports that an officer of CoStar Group, Inc. sold 1,841 shares of the company’s common stock on 11/13/2025.

Who is the reporting person in the CoStar Group (CSGP) Form 4 and what is their role?

The reporting person is an officer of CoStar Group, Inc. serving as the Chief Accounting Officer.

At what price were the CoStar Group (CSGP) shares sold in this insider transaction?

The 1,841 shares of CoStar Group common stock were sold at an average price of $68.79 per share, based on sales prices ranging from $68.78 to $68.85.

How many CoStar Group (CSGP) shares does the insider own after the reported sale?

Following the reported transaction, the officer directly beneficially owned 23,211 shares of CoStar Group common stock.

Were any derivative securities reported in this CoStar Group (CSGP) Form 4?

The section for derivative securities is included in the form, but the provided content only shows details for a sale of non-derivative common stock.

Is this CoStar Group (CSGP) Form 4 filed by one or multiple reporting persons?

The Form 4 is indicated as being filed by one reporting person, not by a group.

What type of security was involved in the CoStar Group (CSGP) insider sale?

The transaction involved CoStar Group, Inc. common stock, par value $0.01 per share.