CHICAGOOmnicom Group Inc. has renewed 112,000 sq. ft. at Michigan Plaza in the downtown, with the advertising and marketing firm now leasing about 212,000 sq. ft. at the 1.9-million.-sq.-ft., two-building complex.

MB Real Estate leases and manages the complex at 205 and 225 N. Michigan Ave. Mark Buth, executive vice president and Kathleen Bertrand, vice president, represented the building in the lease.

Buth said the renewal makes Omnicom the second largest tenant in the 31-year-old building, which recently underwent a capital infusion for tenant amenities such as a conference center and fitness facility. . “We spent several years strategizing and establishing the property as a hub for the marketing group, and those efforts have paid off substantially in the past year,” he said in a statement.