CoStar Group (NASDAQ: CSGP) counsel withholds 428 shares for tax liability

Rhea-AI Filing Summary

CoStar Group, Inc. General Counsel and Secretary Gene Boxer reported a small share disposition related to tax withholding. On March 15, 2026, 428 shares of common stock were delivered at a price of $43.63 per share to satisfy a tax liability. This was reported as a tax-withholding disposition rather than an open-market sale. Following the transaction, Boxer continued to hold 95,517 shares of CoStar common stock directly.

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^*

Boxer Gene

(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)
	General Counsel and Secretary

3. Date of Earliest Transaction (Month/Day/Year)
03/15/2026

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	03/15/2026		F		428	D	$43.63(1)	95,517	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. On March 13, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $43.63.

Remarks:

	/s/ Gene Boxer	03/17/2026
	** 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).
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FAQ

What insider transaction did Gene Boxer report at CoStar Group (CSGP)?

Gene Boxer reported a tax-related share disposition involving 428 CoStar Group common shares. The shares were delivered to satisfy a tax liability, rather than sold in the open market, and were reported as a tax-withholding disposition on a Form 4 filing.

What price was used for Gene Boxer’s tax-withholding shares at CoStar Group (CSGP)?

The tax-withholding disposition used a price of $43.63 per CoStar Group common share. A footnote states this was the Nasdaq closing price on March 13, 2026, the last preceding business day before the March 15, 2026 transaction date.

How many CoStar Group (CSGP) shares does Gene Boxer hold after this Form 4?

After the reported tax-withholding disposition of 428 shares, Gene Boxer directly holds 95,517 shares of CoStar Group common stock. This remaining balance is disclosed in the Form 4 as his total direct ownership following the March 15, 2026 transaction.

Was Gene Boxer’s CoStar Group (CSGP) Form 4 transaction an open-market sale?

No, the transaction was not an open-market sale. It is classified as a tax-withholding disposition, where shares are delivered to cover a tax liability, rather than being sold to another investor through normal market trading.

What role does Gene Boxer hold at CoStar Group (CSGP) in this Form 4 filing?

In this Form 4 filing, Gene Boxer is identified as an officer of CoStar Group, serving as General Counsel and Secretary. The reported transaction reflects activity in his personal direct holdings of CoStar’s common stock.