"Toyota's sales may trail behind Volkswagen in the full-year as well."
GM's US sales climbed to 669,065 vehicles in the second quarter, according to industry researcher Autodata Corp.
The Chevrolet Cruze was the top-selling car in the US market in June and the Chevy Silverado full-size pick-up remained the second- most popular vehicle, behind only Ford's F-Series line.
Hyundai had a 11 per cent jump in first-half deliveries of 1.96 million units.
GM emerged from bankruptcy in 2009 after a US$52 billion taxpayer-funded bailout orchestrated by the Obama administration. The US Treasury still owns 32 per cent of GM's common shares.
The company boosted its second-quarter earnings before interest and taxes by US$1 billion by pushing through higher prices on its vehicles globally.
GM's said its share of global vehicle sales rose to 12.2 per cent in the quarter, from 11.6 per cent a year earlier.
GM's quarterly profit nearly doubled in the second quarter, beating expectations.