<SEC-DOCUMENT>0001057352-16-000169-index.html : 20161101
<SEC-HEADER>0001057352-16-000169.hdr.sgml : 20161101
<ACCEPTANCE-DATETIME>20161101173831
ACCESSION NUMBER:		0001057352-16-000169
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20161031
FILED AS OF DATE:		20161101
DATE AS OF CHANGE:		20161101

ISSUER:		

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

	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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			NASSETTA CHRISTOPHER J
		CENTRAL INDEX KEY:			0001078095

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-24531
		FILM NUMBER:		161965755

	MAIL ADDRESS:	
		STREET 1:		77 WEST WACKER DRIVE
		STREET 2:		SUITE 3900
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60601
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_147803629810379.xml
<DESCRIPTION>FORM 4
<TEXT>
Document 1 - file: wf-form4_147803629810379.html

Document 1 - RAW XML: wf-form4_147803629810379.xml

</DOCUMENT>
</SEC-DOCUMENT>