COSTAR GROUP, INC. — Director's Dealing 2013

Mar 13, 2013

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: COSTAR GROUP INC (CSGP)
CIK: 0001057352
Period of Report: 2013-03-11

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

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2013-03-11	Common Stock, par value $0.01 per share	A	33600	—	Acquired	298944	Direct
2013-03-12	Common Stock, par value $0.01 per share	F	3495	$101.06	Disposed	295449	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2013-03-11	Option to Acquire Common Stock	$102.16	A	56300	Acquired	2023-03-10	Common Stock (56300)	Direct

Footnotes

F1: Represents all shares of Common Stock owned, consisting of 90,443 shares of Common Stock and 208,501 shares of Common Stock subject to unvested Restricted Stock Grants.

F2: Represents all shares of Common Stock owned, consisting of 93,815 shares of Common Stock and 201,634 shares of Common Stock subject to unvested Restricted Stock Grants.

F3: The option vests in three equal installments on March 11, 2014, March 11, 2015, and March 11, 2016.