US light vehicle sales fell 10.5% in June, reflecting the comparison with the same period last year when sales were boosted by aggressive incentives campaigns. Potential car buyers are also thought to be holding off from purchase ahead of incentives campaigns.

As expected, the domestic makers bore the brunt of the sales decline. GM sales were 25.7% down on last year. Sales slipped 15.5% at Chrysler Group and 6.8% at Ford.

But Toyota was up 14.4% over last year.

The seasonally adjusted annualised sales rate (SAAR) for June was 16.3m light vehicles.

GM had warned that its June sales would be down significantly because of aggressive discounts last summer.

Paul Ballew, GM's executive director of global market and industry analysis, said comparisons with last year were difficult because of the promotion, which allowed all customers to purchase vehicles at the price given to employees.

"The Employee Discount for Everyone program and the success of that program was probably a once-in-a-decade home run for the industry and certainly for ourselves," Ballew said.

He said this June's performance was in line with the company's expectations.

GM's truck sales fell 37% in June, while cars were down less than 0.5%.

Year-to-date, GM's sales fell 12.2%.

At Ford, sales of light trucks plummeted 14.6%, but car sales were up 8.6% on last year, helped by high demand for cars such as the Ford Fusion.