US new vehicle sales sales dropped 6% last month compared with April, according to Ward's AutoInfoBank.

Poor May sales by General Motors were blamed for helping car sales drop to their lowest monthly rate for almost four years.

This was despite rebates and reduced interest rates that spread from Detroit-based brands to some top-selling Japanese nameplates during the month.
GM sales fell 11.9%, much the same as Ford's 11.5% drop, while Chrysler Group posted a 4.4% rise.

However, GM raised earnings estimates for the quarter to $2.50 a share from $2 and hiked production estimates, too.

Executives said several factors, such as the ending of special offers for employees and lease buyers, contributed to what they called a one-month sales aberration.

GM reportedly said its overall incentive spending did not reduce and that incentive spending was expected to increase in the second quarter.

Chrysler posted strong Dodge Ram pickup sales in May, up 19% on April's result, together with healthy Jeep Liberty volume.

Fourth-ranked Toyota boosted sales 1.4% in May while arch-rival Honda's sales dropped 4.6%. Nissan boosted volume 1.6% and Hyundai Motor recorded a 9.8% sales increase, bettered by its Kia Motors division's 13.7%.

Various reports suggest that fleet and rental car sales have started to rise following a slump after the September 11 terrorist attacks.

Though Ford retail sales were down 16% in May, fleet sales rose 2%.