General Motors headquarters at the Renaissance Center in Detroit
General Motors posted strong sales gains in March, driven by fuel-efficient and crossover vehicles. Reuters

General Motors Co. (NYSE: GM), the No. 1 U.S. car maker, reported Tuesday 15.5 percent year-over-year U.S. sales growth in June and its best sales month since September 2008.

All four GM brands, Chevrolet, GMC, Buick and Cadillac, reported double-digit sales growth, with Cadillac leading the pack at 26.8 percent growth. Overall, GM sold 248,710 vehicles in June and projected a seasonally adjusted annual rate of sales of 14 million for June, in line with the high end of analyst expectations.

The combination of new products, available credit, lower fuel prices and modest economic growth was a stronger influence on consumer behavior than economic and political uncertainty, Kurt McNeil, GM vice president for U.S. sales and operations, said Tuesday.

GM shares rose 85 cents to $20.42, more than 4 percent, in early Tuesday trading.