CoStar Group, Inc. : CoStar Group to Report Fourth Quarter 2012 Financial Results on February 27, 2013

CoStar Group to Report Fourth Quarter 2012 Financial Results on February 27, 2013 Earnings Release to be Issued After Market Close on Wednesday, February 27; Conference Call to Discuss Fourth Quarter 2012 Financial Results Scheduled for 11:00 AM EDT on Thursday, February 28

WASHINGTON, DC, January 28, 2013 - CoStar Group, Inc. (NASDAQ: CSGP) will announce financial results for the fourth quarter of 2012 following the market close on Wednesday, February 27, 2013. Management will conduct a conference call to discuss the fourth quarter and full-year results at 11:00 AM EDT on Thursday, February 28, 2013.

To participate in the conference call, please dial [phone] (from the United States and Canada) or [phone] (from all other countries) and refer to conference code 279285. To listen to the conference call over the Internet, please access the audio webcast link available in the Investors section of CoStar's website atwww.CoStar.com/investors.aspx.

An audio recording of the conference call will be available for replay approximately one hour after the call's completion and will remain available for a period of time following the call. To access the recorded conference call, please dial [phone] (from the U.S. and Canada) or [phone] (from all other countries) using access code 279285. The webcast replay will also be available in the Investors section of CoStar's website for a period of time following the call.

About CoStar Group, Inc.

CoStar Group (NASDAQ: CSGP) is commercial real estate's leading provider of information, analytics and marketing services. Founded in 1987, CoStar conducts expansive, ongoing research to produce and maintain the largest and most comprehensive database of commercial real estate information. Our suite of online services enables clients to analyze, interpret and gain unmatched insight on commercial property values, market conditions and current availabilities. Through LoopNet, the Company operates the most heavily trafficked commercial real estate marketplace online with more than 6.5 million registered members and 3.5 million unique monthly visitors. Headquartered in Washington, DC, CoStar maintains offices throughout the U.S. and in Europe including the industry's largest professional research organization.www.costar.com.