COSTAR GROUP, INC. — Director's Dealing 2013

Jul 31, 2013

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: COSTAR GROUP INC (CSGP)
CIK: 0001057352
Period of Report: 2013-07-29

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

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2013-07-29	Common Stock, par value $0.01 per share	M	4000	$25.00	Acquired	293196	Direct
2013-07-29	Common Stock, par value $0.01 per share	M	37374	$51.92	Acquired	330570	Direct
2013-07-29	Common Stock, par value $0.01 per share	S	37374	$155.86	Disposed	293196	Direct
2013-07-29	Common Stock, par value $0.01 per share	M	4234	$43.99	Acquired	297430	Direct
2013-07-29	Common Stock, par value $0.01 per share	S	4234	$157.00	Disposed	293196	Direct
2013-07-30	Common Stock, par value $0.01 per share	M	30520	$43.99	Acquired	323716	Direct
2013-07-30	Common Stock, par value $0.01 per share	S	30520	$157.03	Disposed	293196	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2013-07-29	Option to Acquire Common Stock	$25.00	M	4000	Disposed	2019-03-01	Common Stock (4000)	Direct
2013-07-29	Option to Acquire Common Stock	$51.92	M	37374	Disposed	2016-12-11	Common Stock (37374)	Direct
2013-07-29	Option to Acquire Common Stock	$43.99	M	4234	Disposed	2018-02-26	Common Stock (4234)	Direct
2013-07-30	Option to Acquire Common Stock	$43.99	M	30520	Disposed	2018-02-26	Common Stock (30520)	Direct

Footnotes

F1: 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.

F2: Represents all shares of Common Stock owned, consisting of 128,936 shares of Common Stock and 201,634 shares of Common Stock subject to unvested Restricted Stock Grants.

F3: Average based on sales prices ranging from $155.00 to $158.88.

F4: Represents all shares of Common Stock owned, consisting of 95,796 shares of Common Stock and 201,634 shares of Common Stock subject to unvested Restricted Stock Grants.

F5: Represents all shares of Common Stock owned, consisting of 122,082 shares of Common Stock and 201,634 shares of Common Stock subject to unvested Restricted Stock Grants.

F6: Average based on sales prices ranging from $157.00 to $157.26.

F7: The option vested in three equal installments on March 2, 2010, March 2, 2011 and March 2, 2012.

F8: The option vested in three equal installments on December 12, 2007, December 12, 2008 and December 12, 2009.

F9: The option vested in three equal installments on February 27, 2009, February 27, 2010 and February 27, 2011.