[Form 4] CoStar Group Inc Insider Trading Activity

Rhea-AI Filing Summary

John W. Hill, a director of CoStar Group, Inc. (CSGP), reported acquiring 3,177 shares of the company's common stock on 09/09/2025. The reported transaction shows a price of $0 and brings his beneficial ownership to 20,481 shares following the transaction. The Form 4 was signed by Gene Boxer, Attorney-in-Fact, on 09/11/2025. The filing identifies Hill as a director and is a single-reporting-person Form 4. No derivative securities or other transactions are disclosed in this filing.

Insights

Corporate Governance Expert

TL;DR: Insider reported an acquisition of 3,177 shares, modestly increasing director ownership to 20,481 shares.

The Form 4 shows a director-level acquisition with a reported price of $0, which may reflect a non-cash issuance method though the filing does not explain the reason. From a governance perspective, any director purchase is a signal of alignment with shareholders, but the absolute size here is small relative to typical institutional holdings and the filing contains no additional context on source or intent.

Securities Analyst

TL;DR: Reported non-derivative acquisition of 3,177 shares increases reported beneficial holding to 20,481 shares.

This Form 4 documents a straightforward non-derivative transaction dated 09/09/2025 by a director. The report lists 3,177 shares acquired and a post-transaction beneficial ownership of 20,481 shares. The filing contains no information on sale transactions, option exercises, or derivative positions, limiting material market-impact implications.

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^*

Hill John W

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
09/09/2025

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	09/09/2025		A		3,177	A	$0	20,481	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:

Remarks:

	/s/ Gene Boxer, Attorney-in-Fact	09/11/2025
	** 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 transaction did John W. Hill report on Form 4 for CSGP?

The filing reports a non-derivative acquisition of 3,177 shares of CoStar Group common stock on 09/09/2025.

How many CoStar (CSGP) shares does the reporting person own after the transaction?

The Form 4 shows beneficial ownership of 20,481 shares following the reported transaction.

What price is listed for the shares acquired by the director on the Form 4?

The transaction list shows a price of $0 for the acquired shares as reported on the Form 4.

Who signed the Form 4 and when was it signed?

The Form 4 was signed by Gene Boxer, Attorney-in-Fact on 09/11/2025.

Does the Form 4 report any derivative securities or dispositions?

No. The filing contains no entries in Table II and reports no dispositions; only the stated non-derivative acquisition is shown.