CoStar Group and Real Estate Forum Announce 2006 Power Broker Awards

CoStar Group, Inc. (Nasdaq: CSGP), the number one provider of information services to the commercial real estate industry, and Real Estate Forum magazine, the industry's leading news publication, are proud to announce the 2006 CoStar Power Broker award winners.

Awarded to top brokerage firms and dealmakers in 62 markets throughout the United States, the 2006 CoStar Power Broker Award winners conducted billions in lease and sale transactions last year. Only 2.3 percent of more than 118,000 broker agents and 1.3 percent of over 73,000 brokerage firms that were eligible for this highly coveted award were selected.

The CoStar Power Broker Awards, now in their fifth year, recognize brokerage firms and individual brokers for their volume of sales and leasing transactions of office, industrial and retail properties in CoStar's database as of year-end 2006 as well as transaction data supplied by the companies and brokers in each of the 62 markets.

Listings in CoStar's massive database are independently researched, verified and continuously updated by more than 1,000 professionals -- the largest commercial real estate research operation of its kind. Today, CoStar's database contains over 2 million commercial properties representing more than 38 billion square feet of inventory and over 760,000 for-sale and for-lease property listings in the United States, the United Kingdom and France.

A complete list of award winners by market can be found at http://www.costar.com/PowerBrokers/

CoStar's Power Broker Awards are also being co-sponsored by Real Estate Forum magazine, with the winners showcased prominently in upcoming editions of the print publication and online version, GlobeSt.com.

About CoStar Group, Inc.

CoStar Group, Inc. (Nasdaq: CSGP) is the number one provider of information services to commercial real estate professionals in the United States as well as 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 66 U.S. markets as well as 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.

About Real Estate Forum

Over the course of its 60-year history, Real Estate Forum, a publication of ALM, has evolved into the most respected name in commercial real estate business journalism. The magazine's core mission is to provide quality reporting and in-depth analysis of the issues, people and trends impacting the global property marketplace. ALM is a leading integrated media company, focused on the legal and business communities. ALM currently owns and publishes 33 national and regional magazines and newspapers. More information on ALM is available at http://www.alm.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, 2006, under the heading "Risk Factors." In addition to these statements, there can be no assurance that a broker's use of CoStar's information services will result in an increased volume of sales and leasing transactions for that broker. All forward-looking statements are based on information available to CoStar on the date hereof, and CoStar assumes no obligation to update such statements.