J.D. Power and LMC Automotive released their latest report on automotive sales for August and September, noting that fleet sales in September will return to a share of 18 percent, compared with the drop in share to 11 percent that occurred in August.

"Fleet sales have been averaging between 20 and 22 percent annually and typically have a much lower margin than retail sales," said Jeff Schuster, senior vice president of forecasting at LMC Automotive. "Therefore, fleet sales below 18 percent contribute to the overall financial health of the industry."

In general, the pace of new-vehicle sales in September slowed slightly due to fewer selling days and the Labor Day holiday. Total automotive sales in Sept. are expected to rise 4 percent, having been positively affected by fleet sales for the month.

LMC Automotive said its 2013 forecast for total light-vehicle sales will be 15.6 million units, but that retail light-vehicle sales are tracking just ahead of expectations and the company expects they will come in at 12.9 million units.