PRESS RELEASE DETAIL


Dec 27, 2007

CoStar Group Joins NASDAQ Financial-100 Index

2004-07-01 2004 CoStar Group Joins NASDAQ Financial-100 Index

BETHESDA, MD -- CoStar Group, Inc. (NASDAQ: CSGP), today announced that it has been adde...

2004-07-01 2004 CoStar Group Joins NASDAQ Financial-100 Index

BETHESDA, MD -- CoStar Group, Inc. (NASDAQ: CSGP), today announced that it has been added to the NASDAQ Financial-100 Index effective at the beginning of trading this morning.

The NASDAQ Financial-100 Index includes 100 of the largest domestic and international financial companies listed on The NASDAQ Stock Market based on market capitalization. The Index contains financial institutions and related holding companies, insurance companies, real estate companies, broker dealers, investment companies and financial services.

CoStar has produced strong revenue and earnings growth since its IPO in 1998. In its most recent reported public financials, the Company had over $100 million in annualized revenues, and its market capitalization currently has grown to over $800 million.

"We are pleased to be included in this prestigious Index," stated CoStar Group President & CEO Andrew C. Florance. "It is very gratifying to have such prominent recognition of our strong financial achievement."

About CoStar Group, Inc.

CoStar Group, Inc., (NASDAQ: CSGP) is the leading provider of information services to commercial real estate professionals in the United States and the United Kingdom. CoStar's suite of services offers customers access via the Internet to the most comprehensive database of commercial real estate information on over 55 U.S. markets, London and the United Kingdom. Based in Bethesda, MD, the company has approximately 900 employees in 38 offices throughout the United States and the United Kingdom, including the largest professional research organization in the industry.

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-Q for the quarter ended March 31, 2004, under the heading "Risk Factors." All forward-looking statements are based on information available to CoStar on the date hereof, and CoStar assumes no obligation to update such statements.
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