Statement of Changes in Beneficial Ownership (4)

FORM 4 [ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^* Wheeler Scott T	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 Financial Officer
(Last) (First) (Middle) C/O COSTAR GROUP, INC., 1331 L STREET NW	3. Date of Earliest Transaction (MM/DD/YYYY) 3/15/2021
(Street) WASHINGTON, DC 20005 (City) (State) (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	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. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. 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)
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock, par value $0.01 per share	3/15/2021		A		1598	A	⁽¹⁾	29006 ⁽²⁾	D
Common Stock, par value $0.01 per share	3/16/2021		M		3600	A	$342.13	32606 ⁽³⁾	D
Common Stock, par value $0.01 per share	3/16/2021		M		2133	A	$398.15	34739 ⁽⁴⁾	D
Common Stock, par value $0.01 per share	3/16/2021		S		7326	D	$843.28 ⁽⁵⁾	27413 ⁽⁶⁾	D
Common Stock, par value $0.01 per share	3/16/2021		G	V	265	D	$0	27148 ⁽⁷⁾	D
Common Stock, par value $0.01 per share	3/8/2021		G	V	111	D	$0	27037 ⁽⁸⁾	D
Common Stock, par value $0.01 per share	3/8/2021		G	V	37	A	$0	73	I	By Abraham James Wheeler Trust ⁽⁹⁾
Common Stock, par value $0.01 per share	3/8/2021		G	V	37	A	$0	73	I	By Anna Karin Wheeler Trust ⁽¹⁰⁾
Common Stock, par value $0.01 per share	3/8/2021		G	V	37	A	$0	73	I	By Jacob Paul Wheeler Trust ⁽¹¹⁾

*Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)*
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. 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		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 of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)
Option to Acquire Common Stock	$342.13	3/16/2021		M			3600	⁽¹²⁾	2/27/2028	Common Stock	3600.0	$0	0	D
Option to Acquire Common Stock	$398.15	3/16/2021		M			2133	⁽¹³⁾	2/6/2029	Common Stock	2133.0	$0	4267	D

Explanation of Responses:
(1)	Pursuant to the Management Stock Purchase Plan, all or a portion of the reporting person's annual cash incentive amount was converted to Deferred Stock Units (each equivalent to one share of common stock) at $837.86 per unit, and the Company awarded the reporting person Restricted Stock Units that vest in full after four years for an equal number of shares of common stock.
(2)	Represents all shares of Common Stock owned, consisting of 5,009 shares of Common Stock, 18,221 shares of Common Stock subject to unvested Restricted Stock grants, 2,888 shares of Deferred Stock Units and 2,888 shares of unvested Restricted Stock Units.
(3)	Represents all shares of Common Stock owned, consisting of 8,609 shares of Common Stock, 18,221 shares of Common Stock subject to unvested Restricted Stock grants, 2,888 shares of Deferred Stock Units and 2,888 shares of unvested Restricted Stock Units.
(4)	Represents all shares of Common Stock owned, consisting of 10,742 shares of Common Stock, 18,221 shares of Common Stock subject to unvested Restricted Stock grants, 2,888 shares of Deferred Stock Units and 2,888 shares of unvested Restricted Stock Units.
(5)	Average based on sales prices ranging from $840.55 to $846.07.
(6)	Represents all shares of Common Stock owned, consisting of 3,416 shares of Common Stock, 18,221 shares of Common Stock subject to unvested Restricted Stock grants, 2,888 shares of Deferred Stock Units and 2,888 shares of unvested Restricted Stock Units.
(7)	Represents all shares of Common Stock owned, consisting of 3,151 shares of Common Stock, 18,221 shares of Common Stock subject to unvested Restricted Stock grants, 2,888 shares of Deferred Stock Units and 2,888 shares of unvested Restricted Stock Units.
(8)	Represents all shares of Common Stock owned, consisting of 3,040 shares of Common Stock, 18,221 shares of Common Stock subject to unvested Restricted Stock grants, 2,888 shares of Deferred Stock Units and 2,888 shares of unvested Restricted Stock Units.
(9)	Of the shares gifted by reporting person on March 8, 2021, 37 were irrevocably gifted to the Abraham James Wheeler Trust for the benefit of the reporting person's son. The reporting person disclaims beneficial ownership of the securities held by the trust except to the extent of his pecuniary interest therein.
(10)	Of the shares gifted by reporting person on March 8, 2021, 37 were irrevocably gifted to the Anna Karin Wheeler Trust for the benefit of the reporting person's daughter. The reporting person disclaims beneficial ownership of the securities held by the trust except to the extent of his pecuniary interest therein.
(11)	Of the shares gifted by reporting person on March 8, 2021, 37 were irrevocably gifted to the Jacob Paul Wheeler Trust for the benefit of the reporting person's son. The reporting person disclaims beneficial ownership of the securities held by the trust except to the extent of his pecuniary interest therein.
(12)	The option vested in three equal installments on February 28, 2019, February 29, 2020 and February 28, 2021.
(13)	The option vests in three equal installments on February 15, 2020, February 15, 2021 and February 15, 2022.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Wheeler Scott T C/O COSTAR GROUP, INC. 1331 L STREET NW WASHINGTON, DC 20005			Chief Financial Officer