    <SEC-DOCUMENT>0001193125-24-117793-index.html : 20240426
    <SEC-HEADER>0001193125-24-117793.hdr.sgml : 20240426
    <ACCEPTANCE-DATETIME>20240426153057
    ACCESSION NUMBER:		0001193125-24-117793
    CONFORMED SUBMISSION TYPE:	DEFA14A
    PUBLIC DOCUMENT COUNT:		3
    FILED AS OF DATE:		20240426
    DATE AS OF CHANGE:		20240426

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			COSTAR GROUP, INC.
    		CENTRAL INDEX KEY:			0001057352
    		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-BUSINESS SERVICES, NEC [7389]
    		ORGANIZATION NAME:           	07 Trade & Services
    		IRS NUMBER:				522091509
    		STATE OF INCORPORATION:			DE
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		DEFA14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-24531
    		FILM NUMBER:		24883016

    	BUSINESS ADDRESS:
    		STREET 1:		1331 L STREET, NW
    		CITY:			WASHINGTON
    		STATE:			DC
    		ZIP:			20005
    		BUSINESS PHONE:		2023466500

    	MAIL ADDRESS:
    		STREET 1:		1331 L STREET, NW
    		CITY:			WASHINGTON
    		STATE:			DC
    		ZIP:			20005

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	COSTAR GROUP INC
    		DATE OF NAME CHANGE:	19990805
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>DEFA14A
    <SEQUENCE>1
    <FILENAME>d806524ddefa14a.htm
    <DESCRIPTION>DEFA14A
    <TEXT>
    Document 1 - file: d806524ddefa14a.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>2
    <FILENAME>g806524g01p01.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 2 - file: g806524g01p01.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>g806524g02p02.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 3 - file: g806524g02p02.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>