CoStar Showcase Receives Tremendous Market Reception at ICSC Event, Total Subscriptions Surpass $2 Million

BETHESDA, Md., June 4 /PRNewswire-FirstCall/ -- CoStar Group, Inc. (Nasdaq: CSGP), the figure 1 supplier of commercial existent estate
information/marketing solutions, today announced that CoStar Showcase(R)
(), its new online place selling service, has
surpassed $2 million in initial subscription orders. More than 300 houses have
signed up to marketplace their lists through the advanced new service, which
officially debuted at the International Council of Shopping Centers (ICSC)
RECon event held last calendar month inLas Vegas.

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"Based on the enthusiastic response CoStar Showcase received at ICSC, and
continued strong involvement from our clients, it's unclutter there is substantial
demand among commercial place people for a more than effectual manner to
market their place lists online," said CoStar Group Laminitis and CEO

Andrew C. Florance. "We believe CoStar Showcase offerings a better solution, and
we couldn't be more than pleased with the marketplace response for our new online
marketing service. While some of these contracts include a trial time period and an
option to cancel, the response to day of the month clearly bespeaks these clients find
CoStar Showcase to be a very compelling and effectual solution for marketing
their lists online."

The one thousands of up-to-date, research-verified place lists available
free and without enrollment at offering an enormously
valuable resource for those searching for available office, retail,
warehouse/industrial, multifamily, land and other commercial properties. By
going to , visitants can utilize the free place hunt tool
to entree one thousands of available for sale and for rental listings, which are
updated and maintained by CoStar's ain research service, the industry's
largest.

About CoStar Group, Inc.

CoStar Group, Inc. (Nasdaq: CSGP) is the figure 1 supplier of
information/marketing serves to commercial existent estate people inthe
United States as well as theUnited Kingdom. CoStar's suite of services
offers clients entree via the Internet to the most comprehensive database of
commercial existent estate information throughout the U.S. arsenic well as in the
United Kingdom andFrance. Headquartered inBethesda, MD, the company has
approximately 1,300 employees, including the biggest professional research
organization in the industry. For more than information, visit
.

This news release includes "forward-looking statements" including, without
limitation, statements regarding CoStar's expectations, beliefs, purposes or
strategies regarding the future. These statements are subject to many risks
and uncertainnesses that could do existent consequences to differ materially from
these statements. More information about possible factors that could cause
actual consequences to differ materially from those discussed in the
forward-looking statements include, but are not limited to, those declared in
CoStar's filings from clip to clip with the Securities and Exchange
Commission, including CoStar's Form 10-K for the twelvemonth ended December 31, 2007
and CoStar's Form 10-Q for the one-fourth ended March 31, 2008, under the heading
"Risk Factors." In improver to these statements, there can be no assurance
that clients volition go on to demo strong involvement for CoStar Showcase; that
there is significant demand among commercial place people for a more
effective manner to marketplace their place lists online; that CoStar Showcase
offers a better solution; that the response to day of the month bespeaks the clients find
CoStar Showcase to be a very compelling and effectual solution for marketing
their lists online; that the lists available at
will supply an enormously valuable resource for those searching for available
commercial properties; or that visitants to that usage the
free place hunt tool will be able to entree one thousands of available for
sale and for rental listings. All forward-looking statements are based on
information available to CoStar on the day of the month hereof, and CoStar presumes no
obligation to update such as statements.

SOURCE CoStar Group, Inc.