Popular GMC subbrands Denali, AT4 attract more diverse customers

VAIL, Colo. — GMC used to just be General Motors' truck brand. But the automaker has groomed it into a purveyor of high-profit, loyalty-driving subbrands, with the hugely successful Denali line and an expanded collection of AT4 off-roaders poised to soon make up about half of GMC's sales.