The Commercial Union Assurance Building is a 94 m (308 ft), 16-storey office building located in the financial district of San Francisco, California. The building was completed in 1921 and is the same height of the San Francisco City Hall. Both the San Francisco City Hall and the Commercial Union Assurance Building were San Francisco's tallest building(s) until 1922. The much taller 555 California Street is to the west of this Renaissance Revival styled building.