When completed, Kilroy Realty’s “Exchange on 16th” will include 736,000 square feet of office space at 16th and Owens in the Mission Bay Block 40 project. Dropbox just signed a lease to take up all of it. 

The tech company is moving its San Francisco headquarters there from the current location at 333 Brannan St. in South Beach.

Per SocketSite, the lease will be for 15 years but doesn’t include future retail space in the building, which will be added at a later date. 

The sheer size of office space being rented makes it the largest office space lease in the history of San Francisco. Even Facebook’s 181 Fremont St. plans, calling for a “mere” 432,000 square feet of space, pale in comparison to the Dropbox building’s size.

Dropbox plans to make the move late next year when Block 40 is completed.