The Wm. Wrigley Jr. Co., a subsidiary of Mars Inc., is relocating its Global Headquarters from the historic Wrigley Building on Michigan Ave., currently home to a quarter of the company's nearly 1000 Chicago-based associates, to the company's campus on Goose Island in Chicago. The move will be completed by the end of 2012, bringing to a total of nearly 600 associates working on the Goose Island campus.