[Form 4] CoStar Group Inc Insider Trading Activity

Rhea-AI Filing Summary

The filing shows that Rachel C. Glaser, a director of CoStar Group, Inc. (CSGP), acquired 3,143 shares of CoStar common stock on 09/09/2025 at a reported price of $0 (indicating a non‑cash award or gift reporting convention). After the transaction she beneficially owned 3,143 shares directly. The Form 4 was signed by an attorney‑in‑fact on 09/11/2025.

Insights

Financial Analyst

TL;DR: A small, non‑cash acquisition of 3,143 shares by a director; likely immaterial to valuation but notable as insider activity.

The transaction records an acquisition of 3,143 shares with a reported price of $0, which in Form 4 practice can reflect a stock grant, exercise with offset, or other non‑cash issuance rather than a market purchase. The size is modest relative to a large‑cap issuer and does not alone indicate a material shift in ownership or control. Investors typically note insider buys as a behavioral signal, but this filing lacks further detail on the grant type or reason.

Corporate Governance Expert

TL;DR: Director reported a direct acquisition of 3,143 shares; disclosure is routine but missing explanatory detail on transaction nature.

From a governance perspective, timely disclosure under Section 16 is appropriate. The form shows direct ownership and that the reporting person is a director. The $0 price field suggests a non‑cash award or similar issuance, but the filing provides no explanatory remarks. Proper signature by an attorney‑in‑fact is provided, fulfilling filing formalities.

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

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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^*

Glaser Rachel C

(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		3,143	A	$0	3,143	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 Rachel C. Glaser report on Form 4 for CSGP?

The Form 4 reports an acquisition of 3,143 shares of CoStar Group common stock by Rachel C. Glaser on 09/09/2025.

What price was reported for the shares acquired by the director on Form 4?

The reported price is listed as $0 in the filing, indicating a non‑cash issuance or similar reporting convention.

How many shares does the reporting person beneficially own after the transaction?

Following the reported transaction, the filing shows 3,143 shares beneficially owned.

What is Rachel C. Glaser's relationship to CoStar Group (CSGP)?

The Form 4 identifies Rachel C. Glaser as a Director of CoStar Group, Inc.

When was the Form 4 signed and filed for this transaction?

The signature block shows the form was signed by an attorney‑in‑fact on 09/11/2025.