Olmstead Properties is one of the oldest privately held full-service real estate firms in the country. Founded in 1930, Olmstead today owns more than 30 income-producing properties, mostly Class-B office space. It also owns a number of condominiums throughout Manhattan. Olmstead prides itself both on owning nearly three-quarters of the properties in its portfolio and on its aggressive approach to leasing and management. Olmstead also has been aggressive in protecting its turf, such as in 2010 when it sued hotel real estate investment trust Hersha Hospital Trust for $10 million, claiming the trust hired a contractor damaged one of its buildings during demolition for a stalled hotel project near Penn Station. Olmstead also threated to force out a cancer research center out of one of its Varick Street properties, causing New York University to file suit against Olmstead. The firm also has a wide variety of allies, however. In 2015 Olstead partnered with affordable housing developer Jonathan Rose Companies to purchase DKNYs offices in the Garment District.