Pearl Properties has purchased the Art Institute of Philadelphia building at 1618-22 Chestnut St. and will rent three of its lower stories to Gap Inc. for the retailer's second Center City Old Navy store.

Old Navy has leased 23,464 square feet for a flagship store in the art deco building, according to Steven H. Gartner, an executive vice president at commercial real estate services firm CBRE Inc., who brokered the lease.

Pearl Properties closed on its purchase of the building, the former headquarters of radio station WCAU, on Monday, Gartner said. The Art Institute will move its lower-story functions to other parts of the building, where it will remain as a tenant, he said.

Old Navy will continue to operate its branch at the Gallery at Market East shopping mall when the new Chestnut Street location opens in mid-2016, Gartner said.

jadelman@phillynews.com

215-854-2615 @jacobadelman