"Grubb & Ellis Realty Investors is very pleased to have executed this lease, particularly in light of the formidable economic challenges confronting the national and Chicago real estate markets," Kent Peters, EVP of Asset Management, says. "In the midst of a difficult leasing atmosphere, we have been able to further stabilize Congress Center and realize additional revenue on behalf of investors."

Mark Parrish, SVP of Grubb's Chicago office, represented Grubb & Ellis Realty Investors in the deal, while GSA was represented by Jason Volpe and Jason Lichty of Studley. GSA's lease brings the building to 84% occupied, with other tenants including Amtrak, Azko Nobel and North American Insurance. The building offers proximity to Union Station, the Chicago Transit Authority lines and Congress Expressway.

Grubb & Ellis reportedly assumed the building, at 525 W. Van Buren St., in 2007, after merging with NNN Realty Advisors, the parent company of real estate investment firms including Triple Net Properties, which last purchased the 16-story property five years ago. The building was completed in 2001 and has a 40-space indoor parking garage in addition to a 1,700-car parking garage. The building has a two-story lobby with 20-foot ceilings and column-free floors with a center-core design.