Sears is no longer headquartered in this building, having sold the building and moved out to Hoffman Estates, Illinois in 1992.
The building's structure is a "bundled tube" system of nine squares with sides of 75 feet (for an overall width of 225 x 225 ft btw. exterior column lines and 229' at outside faces). Height to width ratio is 6.45:1. The tower was completed for $160 Million and used 76,000 tons of steel, 72,000 cubic yards of concrete, 17,500 tons of mechanical equipment. At peak construction, over 2,400 workers were on site representing 60 different subcontractors. There are 76 single-deck elevators in addition to 14 double-deck elevators, bringing the total to 104 cabs. Other impressive quantities include 25,000 miles of plumbing and 2,000 miles of electrial wire.
The two level mechanical penthouse brings the total floor count to 110.
The "Skydeck Pavilion" entrance on Wacker Drive was added in 1985, the large antennas in 1982, and the 4 HDTV antennas in 1999 (or thereabouts). Extra height was added to the western antenna on 5th June 2000.