Under a deal struck by General Motors and the United Auto Workers, 17.5% of the company's shares will be owned by a union healthcare trust, with an option for up to 20% over time. That's down from an earlier offer of 39%. In exchange for getting a 17.5% stake as well as other concessions from GM, the union is making healthcare concessions of its own. Retiree health benefits will be cut immediately, leaving thousands of retirees to pay more out-of-pocket for their healthcare.