CoStar Group (CSGP) CAO reports tax-withholding share disposition on Form 4

Rhea-AI Filing Summary

COSTAR GROUP, INC. Chief Accounting Officer Cynthia Cammett reported a routine tax-related share disposition. On March 15, 2026, 1,194 shares of common stock were withheld at a price of $43.63 per share to cover tax obligations, rather than sold on the open market. Following this transaction, she directly holds 25,148 shares, indicating she retains the vast majority of her equity position.

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)
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		1,194	D	$43.63(1)	25,148	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, Attorney-in-Fact	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).
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 for Cynthia Cammett?

CoStar Group reported that Chief Accounting Officer Cynthia Cammett had 1,194 shares of common stock withheld to cover tax obligations. This was a tax-withholding disposition, not an open-market sale, and is a typical mechanism when equity awards vest or are exercised.

Was Cynthia Cammett’s CoStar Group (CSGP) Form 4 transaction a stock sale?

No, the Form 4 shows a tax-withholding disposition of 1,194 shares at $43.63 per share, not an open-market sale. These shares were delivered to satisfy tax liabilities associated with equity compensation, a routine administrative transaction rather than a discretionary sale.

How many CoStar Group (CSGP) shares does Cynthia Cammett hold after this Form 4?

After the tax-withholding disposition, Cynthia Cammett directly holds 25,148 shares of CoStar Group common stock. This indicates that the 1,194 shares used to satisfy tax obligations represent a relatively small portion of her overall reported equity position in the company.

What price was used for Cynthia Cammett’s tax-withholding shares in CoStar Group (CSGP)?

The tax-withholding disposition used a price of $43.63 per share for the 1,194 CoStar Group common shares. A footnote notes this matches the closing price of the company’s stock on Nasdaq on March 13, 2026, the last preceding business day.

What does transaction code “F” mean in CoStar Group (CSGP) insider filings?

Transaction code “F” on the Form 4 indicates payment of an exercise price or tax liability by delivering securities. For CoStar Group, Cynthia Cammett’s filing shows an “F” code for 1,194 shares, confirming the shares were used to cover tax obligations related to equity compensation.

Is Cynthia Cammett’s CoStar Group (CSGP) Form 4 likely to be a major signal for investors?

The Form 4 reflects a routine tax-withholding disposition of 1,194 shares, with 25,148 shares still held directly. Because this is an administrative step to cover tax liabilities rather than an open-market sale, it generally carries limited signaling value about her view of the stock.