Updated from 12:30 p.m. EDT
, one of the world's largest advertisers, said Monday that it would consolidate all of its $2.6 billion in media planning duties at one advertising agency.
GM, which currently uses 17 ad agencies to handle both national and local advertising, has narrowed the field to three contenders -- the
Interpublic Group of Cos.
in New York, privately held
Bcom3 Group's Starcom MediaVest Group
in Chicago and
Carat North America
, a unit of British-based
The review is one of the biggest ever of its kind, and the stakes for the competing agencies are huge. Carat, for example, would more than double its U.S. account billings should it pick up the account. Senior executives at each agency are leading their respective pitches for the business, according to the trade publication
The decision to consolidate comes three months after John Middlebrook took over as the Detroit-based automaker's marketing chief, following Phil Guarascio's retirement.
The proposed consolidation would follow the shift of more than $3 billion in media-buying duties to Interpublic's
in Warren, Mich., several years ago. Mediaworks will continue to handle media buying for the company, said Peg Holmes, a GM spokeswoman.
The three finalists are expected to submit proposals by the end of July, and a final decision is expected this fall. The winner will handle ad planning for five GM vehicle divisions -- Chevrolet, GMC, Oldsmobile, Buick and Cadillac -- and GM's regions around the U.S.
Middlebrook told the trade publication
that he does not plan any major shifts in ad spending or strategy beyond possibly consolidating media planning duties, a move that is being made to increase operating efficiencies.
GM's shares closed down 1 1/4, or 2%, at 60 7/16 Monday.