The Detroit automaker reported a 2.2% drop in third-quarter sales compared with a year earlier, slipping to 659,601 vehicles sold. Auto industry forecasters such as Cox Automotive and Edmunds had expected GM's sales to be down by more than 3% during that time.

GM's third-quarter sales are expected to be in line with the overall industry. Cox Automotive and Edmunds project third-quarter sales industrywide will be down roughly 2% compared to a year earlier.