PRESS RELEASE

CoStar Group, Inc. (NASDAQ: CSGP) today announced that a federal judge in Los Angeles has entered a wide-ranging injunction against Apartment Hunters, Inc., (apartmenthunterz.com) based in Dana Point, California, finding it liable for publishing listings and photographs stolen from CoStar's Apartments.com. The judge ordered Apartment Hunters to stop its misconduct, add a copyright filter to its system, and pay $10,000 per day, per photograph if further copyright infringement occurs.  On top of the judgment, Apartment Hunters will also immediately pay CoStar $10,000 per stolen listing and $10,000 per infringed image.

"CoStar creates thousands of valuable U.S. jobs for researchers and photographers who work hard to collect apartment information that helps millions of Americans find their next apartment online,” said Andrew Florance, CoStar Founder and CEO.  "When companies like Apartment Hunters republish information stolen from our website it destroys the ability of honest hardworking people to innovate and make a living.  Likewise, if investors provide a billion dollars to CoStar to fund extensive collection of information that is valuable to millions of renters, those investors need to know that a company like Apartment Hunters cannot casually publish that information and call it their own. The judge’s order to Apartment Hunters to stop misappropriating Apartments.com listings, and to immediately pay CoStar $10,000 per stolen listing and $10,000 per infringed image, sends a clear message that theft is not a viable business model. "

Despite Apartment Hunters refusal to admit that it had intentionally stolen the listings and photos it published on its websites, the judge found Apartment Hunters liable for misappropriating listings and infringing photos found on Apartments.com.  The sweeping federal injunction prohibits Apartment Hunters from further misappropriation of listings and infringement of photos, and forces Apartment Hunters to use new third-party monitoring software to seek to block further infringement.  

"We brought this case based on clear evidence that Apartment Hunters was misappropriating our listings and infringing our photographs," said CoStar General Counsel Jon Coleman. "Apartment Hunters inappropriately and unsuccessfully tried to blame brokers for uploading the listings and photos, but ultimately could not evade the truth and justice.  The liability finding and injunction represent a big win for our Company and all of our stakeholders. We will continue to take all necessary steps to protect our customers and vindicate our intellectual property rights, including swift action against those companies whose idea of competition amounts to copying our content, whether listings, data or photographs."

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About CoStar Group

CoStar Group, Inc. (NASDAQ: CSGP) is the leading provider of commercial real estate information, analytics and online marketplaces. 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. LoopNet is the most heavily trafficked commercial real estate marketplace online with more than 10 million registered members. Apartments.com, ApartmentFinder.com, ApartmentHomeLiving.com and Westside Rentals form the premier online apartment resource for renters seeking great apartment homes and provide property managers and owners a proven platform for marketing their properties. Through an exclusive partnership with Move, a subsidiary of News Corporation, Apartments.com is the exclusive provider of apartment community listings across Move's family of websites, which include realtor.com®, doorsteps.com and move.com.  CoStar Group's websites attracted an average of nearly 24 million unique monthly visitors in aggregate in 2016.  Headquartered in Washington, DC, CoStar maintains offices throughout the U.S. and in Europe and Canada with a staff of over 3,000 worldwide, including the industry's largest professional research organization. For more information, visit www.costargroup.com.

This news release includes "forward-looking statements" including, without limitation, statements regarding CoStar's expectations, beliefs, intentions or strategies regarding the future. These statements are based upon current beliefs and are subject to many risks and uncertainties that could cause actual results to differ materially from these statements. The following factors, among others, could cause or contribute to such differences: the risk that CoStar is unable to collect the damages or other amounts from Apartment Hunters that are stated in this release, the risk that Apartment Hunters and its management team fail to comply with the injunction and the agreement with CoStar, and the risk that despite being vigilant we are unable to take swift action against infringers of our intellectual property.  More information about potential factors that could cause actual results to differ materially from those discussed in the forward-looking statements include, but are not limited to, those stated in CoStar's filings from time to time with the Securities and Exchange Commission, including in CoStar's Annual Report on Form 10-K for the year ended December 31, 2016, which is filed with the SEC, including in the "Risk Factors" section of the filing, as well as CoStar's other filings with the SEC available at the SEC's website (www.sec.gov). All forward-looking statements are based on information available to CoStar on the date hereof, and CoStar assumes no obligation to update such statements, whether as a result of new information, future events or otherwise.