The name says "corporate" but it's really about the government. A real estate investment trust (REIT), Corporate Office Properties Trust owns and manages some 175 properties totaling some 17 million sq. ft. of leasable space. The REIT focuses on large suburban business parks near federal government hubs and military installations. More than 85% of its office space is located in in the Greater DC/Baltimore regions; other major markets include Northern Virginia, San Antonio, and Hunstville, Alabama. Subsidiaries provide property management, construction and development, and HVAC services. Founded in 1998, the REIT's largest tenants are the US Government and defense information technology concerns.