CoStar Surpasses One Million Property Listings

Ritchie Commercial Broker Cyrus Weiss Won $25,000 when his San Francisco
Retail Property Became CoStar's One-Millionth Listing

BETHESDA, Md., May 15 /PRNewswire-FirstCall/ -- CoStar Group, Inc.
(Nasdaq: CSGP), the number one provider of commercial real estate
information/marketing solutions, today announced that the total number of for
sale and for lease listings in its online database of commercial real estate
information surpassed one million listings this week. This unprecedented
amount is believed to be the largest number of commercial property listings
ever assembled by a single information provider.
(Photo: here )
(Logo: here )
According to CoStar Group Founder and CEO Andrew C. Florance, crossing a
milestone of one million online listings marks the commercial real estate
industry's transition from primarily a paper-based industry to a
sophisticated, more-efficient, and more-transparent digital marketplace.
"CoStar pioneered the concept of commercial real estate firms outsourcing
their property information functions 20 years ago, fundamentally changing the
way commercial real estate professionals access, use and share property
information," Florance said. "The astounding number of listings being accessed
today across CoStar's information platform by tens of thousands of users
throughout the U.S. and U.K. is a clear indication of how far the industry has
changed from the outmoded and inefficient paper-based information exchange of
the past, to the greater efficiency, increased productivity and cost-savings
that result from using CoStar."
Among the major information providers currently serving commercial real
estate, only CoStar can bring the resources of a more than 900-person research
team to actively seek out, confirm and update listing information on
commercial properties.
From a competitive market share perspective, Florance said the
million-plus listings in CoStar's database far outpaces the amount of listings
available from other commercial real estate listing firms. "There's no
comparison. In fact, based on the listing totals reported by our next largest
competitors in both the U.S. and U.K., CoStar has more listings than both of
them combined," he said.
As confirmed by CoStar Research, the one-millionth property listing is a
three-level storefront retail and office building at 1674-76 Lombard Street in
San Francisco listed with CoStar this week by Cyrus Weiss of Ritchie
Commercial, a longtime CoStar client.
To commemorate this important milestone, Mr. Florance personally visited
Mr. Weiss to thank him for listing his property with CoStar, and to inform him
that he had won a new Toyota Prius hybrid car. While thrilled to learn that
his was the one millionth listing on CoStar, Mr. Weiss responded that he no
longer drove a car and that he preferred that his prize be awarded in CoStar
stock!
CoStar agreed and plans to deposit $25,000 into an account of Mr. Weiss'
choosing that he can then use to purchase CoStar stock.
Mr. Weiss uses CoStar Group information services to search for properties
and to market his listings. With one call to CoStar Research, Mr. Weiss made
his listing available to three key audiences as part of CoStar's multiple
channel, 'one-stop shop' service: to other commercial real estate service
providers through CoStar Property Professional(R); to Ritchie Commercial's
client base through the firm's web site via CoStar Connect(R); and to an
enormous online audience that visits www.CoStar.com, which includes 1.3
million unique visitors quarterly, all of whom have access to his listing
through CoStar Showcase(R).
About CoStar Group
CoStar Group, Inc. (Nasdaq: CSGP) is the number one provider of commercial
real estate information/marketing services to commercial real estate
professionals in the United States and United Kingdom. CoStar's suite of
services offers customers access via the Internet to the most comprehensive
database of commercial real estate information throughout the U.S. as well as
in the United Kingdom and France. Headquartered in Bethesda, MD, the company
has approximately 1,300 employees, including the largest professional research
organization in the industry. 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 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 Form 10-K for the year ended December 31, 2007 and CoStar's
Form 10-Q for the quarter ended March 31, 2008, under the heading "Risk
Factors." In addition to these statements, there can be no assurance that
CoStar's database of commercial real estate information has the largest number
of commercial property listings ever assembled by a single information
provider; that all subscribers will experience greater efficiency, increased
productivity and cost-savings from using CoStar; that Mr. Weiss will
ultimately choose to purchase CoStar stock with his award; and that the
Ritchie Commercial listing will be accessible as indicated in this release.
All forward-looking statements are based on information available to CoStar on
the date hereof, and CoStar assumes no obligation to update such statements.
SOURCE CoStar Group, Inc.

Timothy J. Trainor, Communications Director at CoStar Group, Inc.,
+1-301-280-7695, ttrainor@costar.com