Traditional Monday miseries were compounded this week in Detroit as top US automaker General Motors learned its March sales were down year-on-year by 14.3%.

Gloom too at Ford Motor Company, albeit on a lesser scale, as executives chewed on a 4.6% sales decline.

In marked contrast, Japanese giant Toyota broke out the sake to celebrate a 6.9% uplift in units traded. There was cause too for mild jubilation at DaimlerChrysler's Chrysler unit, where sales edged-up 1.6%.

According to GM sales analyst Paul Ballew, incentive marketing by rivals was "a bit more aggressive than we expected to see", notably on leased vehicles. Chrysler, Ballew noted, was "especially aggressive".

He pinpointed mid-size SUVs as the weakest link in GM's sales chain. "The category is under a lot of pressure," he said

Among European manufacturers, Volkswagen led the pack with sales rising by nearly 19%, thanks to new Passat and Jetta models. .

Despite attempts by the industry to curb incentivization, the practice remains at near-record levels, not least among Japanese and European manufacturers. In terms of sweeteners, however, they were eclipsed by the extravagance of US manufacturers

Total US car and light truck sales, according to preliminary March figures from Autodata, are estimated at a seasonally-adjusted annual rate of 16.7m vehicles, up year-on-year by about 2.5%.

Data sourced from Financial Times Online; additional content by WARC staff