DETROIT—Union workers at Detroit's two largest auto makers are on track for big profit-sharing payouts for this year.

Officials at the United Auto Workers union have told members employed at General Motors Co. to expect profit-sharing checks for as much as $7,000 early next year, according to two people briefed on the matter. Over at Ford Motor Co., which is more profitable than GM in North America, the 2012 payouts could top $8,000, based on a pay formula spelled out in the UAW contract.

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