About SL Green Realty Corp. SL Green Realty Corp., Manhattan's largest office landlord, is a fully integrated real estate investment trust, or REIT, that is focused primarily on acquiring, managing and maximizing the value of Manhattan commercial properties. As of March 31, 2024, SL Green held interests in 57 buildings totaling 32.4 million square feet. This included ownership interests in 28.7 million square feet of Manhattan buildings and 2.8 million square feet securing debt and preferred equity investme ...