Chicago-based Equity Office Properties Trust has signed a national agreement with Bethesda, Md.-based CoStar Group to use the CoStar Property inventory tool in 18 top markets around the country. Under the deal, CoStar Property will help Equity Office Properties monitor market activity, analyze supply and demand fluctuations, and track portfolio performance.

CoStar Property is the newest addition to Equity Office Properties’ current range of research methods. The property owner also uses Torto Wheaton Research (a division of Los Angeles-based CB Richard Ellis), New York-based Reis Inc., West Chester, Pa.-based Economy.com and New York-based Bloomberg L.P., in addition to its own field research. According to Equity Office Properties officials, CoStar Property data allows for custom building analysis and daily updates on a national level, while other data services provide more general market analysis.

The Equity Office Properties-CoStar agreement includes New York, Boston, Chicago, Atlanta, Washington, D.C., Philadelphia, Dallas, Houston, Denver, Seattle, Stamford, Conn., and the California markets of San Jose, Oakland, San Francisco, Los Angeles, Orange County, Sacramento and San Diego.