Insurance company Health Care Services Corporation leased about 65,000 square feet across two floors at the Aon Center, joining another office expansion to push the supertall to 94 percent occupancy.
The city’s buildings department issued a permit for work on the 39th and 40th floors, records show. Building owner 601W Companies is readying the space for Health Care Services Corporation to move in by the end of March, according to Steve Smith, executive vice president of the Telos Group, which oversees leasing of the 83-story tower.
Health Care Services, which operates Blue Cross Blue Shield health plans across five states, is expanding beyond its existing headquarters at the 54-story Blue Cross Blue Shield building next door.
601W also secured permits this month to build out a new tenant space for health care company Strata Decision Technology, which is expanding its footprint in the tower to about 67,000 square feet across the 49th and 50th floors, Smith said.
601W took out a $678 million loan on the 2.8-million-square-foot Aon Center in June, three years after it paid $713 million to buy the property from Piedmont Office Realty Trust.
Soon after the refinancing, 601W announced a $185 million plan to grab a slice of the city’s booming tourism industry by adding an exterior elevator shaft and a levered observation pod that would hang thrill-seeking visitors over the roof.
The Chicago Plan Commission approved the addition last month.
New York-based 601W also landed a $310 million loan last month for the acquisition and renovation of the 40-story tower at 1 South Wacker Drive, which was by far the priciest office sale recorded in Chicago in December.