COSTAR GROUP, INC. — Director's Dealing 2013

Oct 30, 2013

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: COSTAR GROUP INC (CSGP)
CIK: 0001057352
Period of Report: 2013-10-28

Reporting Person: FLORANCE ANDREW C (Director, President and CEO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2013-10-28	Common Stock, par value $0.01 per share	M	54400	$25.00	Acquired	347596	Direct
2013-10-28	Common Stock, par value $0.01 per share	S	54400	$179.08	Disposed	293196	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2013-10-28	Option to Acquire Common Stock	$25.00	M	54400	Disposed	2019-03-01	Common Stock (54400)	Direct

Footnotes

F1: Represents all shares of Common Stock owned, consisting of 145,962 shares of Common Stock and 201,634 shares of Common Stock subject to unvested Restricted Stock Grants.

F2: Average based on sales prices ranging from $177.92 to $179.67.

F3: Represents all shares of Common Stock owned, consisting of 91,562 shares of Common Stock and 201,634 shares of Common Stock subject to unvested Restricted Stock Grants.

F4: The option vested in three equal installments on March 2, 2010, March 2, 2011, and March 2, 2012.