 Autochannel (press release) | General Motors gives Buick, Pontiac and GMC ad business to one agency DetNews.com, MI - General Motors Corp. said today that one advertising agency will handle creative work for GM's Buick, Pontiac and GMC brands effective October 1. ... Burnett wins 2 GM ad accounts General Motors to Change Ad Agency Ad agency gains Buick, GMC after Cadillac loss |