Image courtesy of Elkus Manfredi Architects

A 372,000-square-foot Seaport District office building fully leased to Cengage Learning, Man Consulting and Boston Consulting Group has been acquired by a California investor for $450 million.

Developer Tishman Speyer sold the property to CommonWealth Partners, a Los Angeles-based real estate firm that owns class A office buildings and mixed-use properties in major U.S. metros. At $1,208 per square foot, the price is the highest ever paid for a Boston office property, Tishman Speyer said.

Tishman Speyer paid $71 million for the former Anthony’s Pier 4 restaurant property in 2014 and partnered with a pair of Chinese insurers on the $500 million development, which includes a second building with 106 luxury condominiums and a 1-acre public park scheduled for completion in 2019.

Developers leased 202,000 square feet to Boston Consulting Group in June 2016, and Cengage leased 117,000 square feet to replace its 20 Center Channel St. headquarters and complete the lease-up.