COSTAR GROUP, INC. — Director's Dealing 2012

Feb 23, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: COSTAR GROUP INC (CSGP)
CIK: 0001057352
Period of Report: 2012-02-21

Reporting Person: Radecki Brian J (Chief Financial Officer)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-02-21	Common Stock, par value $0.01 per share	A	44000	—	Acquired	76530	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-02-21	Option to Acquire Common Stock	$58.95	A	13900	Acquired	2022-02-20	Common Stock (13900)	Direct

Footnotes

F1: Includes a grant of 9,900 shares of restricted common stock that vest in three equal installments on February 21, 2013, February 21, 2014, and February 21, 2015, and a grant of 34,100 shares of restricted common stock that vest upon CoStar Group, Inc.'s achievement of $90 million of cumulative earnings before interest depreciation and amortization (EBITDA) over a period of four consecutive calendar quarters by March 31, 2017.

F2: Represents all shares of common stock owned, consisting of 19,163 shares of Common Stock and 57,367 shares of Common Stock subject to unvested restricted common stock grants.

F3: The option vests in three equal installments on February 21, 2013, February 21, 2014, and February 21, 2015.