All else being equal, Equity Office is one of the largest commercial landlords in the US. The company owns a commercial building portfolio (350 properties with 4,800 tenants) of more than 50 million sq. ft. of premiere Class A office space in the country's top markets, including Boston, Manhattan, Los Angeles, and Northern California. Equity Office has experience with major renovations and developments. The company also handles large corporate leases. Former chairman Sam "Grave Dancer" Zell founded Equity Office in 1976. The company is now owned by The Blackstone Group.