GFP Real Estate and Northwind Group have agreed to buy 7 Hanover from Guardian Life Insurance Company of America for $308.5 million.
Guardian has had its headquarters in the 29-story building, which is in lower Manhattan, since 1999.
The life, annuity and disability issuer plans to move its headquarters farther north, and to the west, to Hudson Yards.
Cushman & Wakefield's Doug Harmon and Adam Spies brokered the 7 Hanover deal. The parties expect to complete the transaction in September 2019.