It is believed that Starcom and ZenithMedia are vying for the Cadillac business, while Universal McCann and Zenith are gunning for Chevrolet.
A decision is expected within a month.
Earlier this year, SGM retained Leo Burnett as its creative agency for Cadillac after a six-month review, and appointed McCann-Erickson to work on Chevrolet. General Motors announced plans to export Cadillac into China next year, when China relaxes quotas on car imports.
Anticipating heightened competition as new trade rules open doors for many new brands to come to market, SGM recently unveiled a series of price-cuts for its Buick range. Buick is currently serviced by Bates on the creative side and Zenith for media, and is not thought to be up for review.
SGM, a joint-venture between General Motors and Shanghai Automotive Industry Corporation, sold over 200,000 vehicles last year, 80 per cent more than 2002. Its share of the passenger car market stands at just below 10 per cent. Overall car sales in China last year nestled just under two million.