Director Louise S. Sams buys 1000 CoStar Group (CSGP) shares

Rhea-AI Filing Summary

CoStar Group director buys additional shares. Louise S. Sams, a director of CoStar Group, Inc., purchased 1000 shares of common stock in an open-market transaction at a price of $48.3600 per share. Following this purchase, Sams directly holds a total of 20409 CoStar Group shares.

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^*

Sams Louise S

(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)
03/06/2026

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	03/06/2026		P		1,000	A	$48.36	20,409	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:

Exhibit 24 - Power of Attorney

	/s/ Gene Boxer, Attorney-in-Fact	03/09/2026
	** 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.

FAQ

What insider transaction did CoStar Group (CSGP) disclose for Louise S. Sams?

CoStar Group director Louise S. Sams bought 1000 common shares in an open-market transaction. The purchase price was $48.3600 per share, increasing her direct holdings to 20409 shares of CoStar Group, Inc. common stock after the transaction.

How many CoStar Group (CSGP) shares did Louise S. Sams buy and at what price?

Louise S. Sams purchased 1000 shares of CoStar Group common stock at $48.3600 per share. This open-market purchase increased her direct ownership position, as reported in the Form 4 insider trading filing for CoStar Group, Inc.

What is Louise S. Sams’ total CoStar Group (CSGP) share ownership after this Form 4 transaction?

After the reported transaction, Louise S. Sams directly owns 20409 shares of CoStar Group common stock. This total reflects the addition of 1000 shares purchased in an open-market transaction at $48.3600 per share, according to the insider trading disclosure.

Was the recent CoStar Group (CSGP) insider transaction a purchase or sale?

The recent CoStar Group insider transaction was a purchase. Director Louise S. Sams executed an open-market buy of 1000 common shares at $48.3600 per share, increasing her direct holdings to 20409 CoStar Group, Inc. shares following the transaction.

What type of security did Louise S. Sams trade in CoStar Group (CSGP)?

Louise S. Sams traded CoStar Group’s common stock, par value $0.01 per share. She bought 1000 shares in an open-market purchase at $48.3600 per share, and now directly holds a total of 20409 common shares, as reflected in the Form 4 filing.