Although financial terms were not disclosed, Prime Group Realty Trust, which owns the building with Orlando-based Estein & Associates USA, Ltd., is marketing space at 131 S. Dearborn St. at rates beginning at $22 per sf. That would put the value of the deal at $100 million of its life.

"We believe that Bank One Center's state-of-the-art infrastructure and amenities meet our needs for high-quality office space," says Seyfarth Shaw managing partner Stephen Poor. Jones Lang LaSalle managing director Melissa Copley and senior vice president Steve Steinmeyer represented the law firm in negotiations with Prime Group Realty Trust president and chief executive officer Jeffrey A. Patterson and senior vice president John F. Bucheleres.

Seyfarth Shaw has other US offices in Atlanta, Boston, Houston, Los Angeles, New York, Sacramento, San Francisco and Washington, DC. The firm has 240 attorneys working in its Chicago office.