CoStar Group's LoopNet Traffic Jam Campaign Wins "Best of Show" in 2013 Summit Awards

CoStar Group's LoopNet Traffic Jam Campaign Wins "Best of Show" in 2013 Summit
Awards

Honor Recognizes Excellence in Integrated Marketing Campaign for LoopNet
Premium Lister

WASHINGTON, June 6, 2013 (GLOBE NEWSWIRE) -- CoStar Group, Inc. (Nasdaq:CSGP),
commercial real estate's leading provider of information, analytics and
marketing services, today announced that it received "Best of Show Campaign"
honors in the Summit International Awards for a national, integrated marketing
campaign supporting its LoopNet Premium Lister product.

Combining print, digital and outdoor multi-media, the campaign focused on the
theme that if a property isn't advertised with a premium listing on
LoopNet.com, it might as well be invisible. The campaign launched in 2012 with
a series of direct mail and email communications and online display ads. In
January 2013, the campaign culminated with LoopNet's ground-breaking "LA
Traffic Jam" event, when a live audience witnessed a stunning visual effect
that made a 12-story building in downtown Los Angeles appear to vanish before
their eyes. The award-winning marketing campaign was developed by Creative i,
a Palo Alto-based integrated communications firm.

"Premium Lister leverages LoopNet.com's powerful online marketing platform to
help commercial real estate brokers and owners achieve maximum exposure for
their listings with tenants and buyers," said CoStar Founder and CEO Andrew C.
Florance. "This powerful product is deserving of an equally impactful
marketing campaign, and we are thrilled with the results. Receiving this
recognition from Summit International is a tremendous honor in addition to the
positive response we've received from our clients."

The 2013 Summit Creative Award competition received more than 5,000
submissions from 25 countries. Over the past 19 years, the Summit
International Awards organization (SIA) has established itself as one of the
premier arbiters of creative excellence. Entries in 23 major categories were
judged against a stringent set of standards. International judges searched for
innovative and creative concepts, strong executions and the ability to
communicate and persuade.

About the Summit International Awards

The Summit International Awards (SIA) organization is dedicated to furthering
excellence in the marketing communications industry. It administers three
distinguished advertising and marketing award competitions throughout the year
with the goal of raising the awareness of companies and individuals who have
the creative and marketing talent to go beyond the ordinary.

The SIA is the oldest and most prestigious organization that administers an
advertising award exclusively for firms with limited billings. Throughout its
19-year history, its Creative Award has established itself as a premier
arbiter of creative and communication excellence. Using stringent evaluation
criteria and blind judging processes, its competitions reward only those firms
whose work exemplifies the best in its class. For more information, visit
http://www.summitawards.com/.

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 7 million
registered members. CoStar operates websites that have approximately 10
million unique monthly visitors in aggregate. Headquartered in Washington, DC,
CoStar maintains offices throughout the U.S. and in Europe with a staff of
approximately 2,000 worldwide, including the industry's largest professional
research organization. For more information, visit www.costar.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. 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 CoStar's Annual Report on Form
10-K for the year ended December 31, 2012, and CoStar's Quarterly Report on
Form 10-Q for the quarter ended March 31, 2013, under the heading "Risk
Factors" in each of these filings. 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.

CONTACT: ALL INQUIRIES:
         Mark Klionsky
         (202) 623-5252
         mklionsky@costar.com