By new GM, we mean the brands that General Motors continues to operate in the United States: Buick, Cadillac, Chevrolet, and GMC. By old GM, we mean the brands GM no longer operates in the United States: Hummer, Oldsmobile, Pontiac, Saab, and Saturn. GM's market share through the first five months of 2014 - 17.61% - is down from 17.97% during the first five months of 2013.