COSTAR GROUP, INC. — Director's Dealing 2012

Sep 20, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: COSTAR GROUP INC (CSGP)
CIK: 0001057352
Period of Report: 2012-09-18

Reporting Person: KLEIN MICHAEL R (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-09-18	Common Stock, par value $0.01 per share	S	27011	$82.94	Disposed	394379	Direct
2012-09-19	Common Stock, par value $0.01 per share	S	29840	$83.34	Disposed	364539	Direct
2012-09-20	Common Stock, par value $0.01 per share	S	43149	$81.74	Disposed	321390	Direct

Footnotes

F1: Average based on sales prices ranging from $82.72 to $83.27.

F2: Represents all shares of Common Stock owned, consisting of 391,771 shares of Common Stock and 2,608 shares of Common Stock subject to unvested Restricted Stock Grants.

F3: Average based on sales prices ranging from $82.69 to $84.01.

F4: Represents all shares of Common Stock owned, consisting of 361,931 shares of Common Stock and 2,608 shares of Common Stock subject to unvested Restricted Stock Grants.

F5: Average based on sales prices ranging from $81.32 to $83.24.

F6: Represents all shares of Common Stock owned, consisting of 318,782 shares of Common Stock and 2,608 shares of Common Stock subject to unvested Restricted Stock Grants.