BMW said sales of its brands, which include Mini and Rolls-Royce, shed 18.3 percent in May on a 12-month basis, a figure that was nonetheless better than April's drop of 24 percent.
Daimler's Mercedes-Benz division said May sales were off by 12.4 percent, but that was almost half the loss of nearly 24 percent reported in April. In Germany, which represents roughly one-quarter of all Mercedes sales, the group even saw an increase of 11 percent.
Audi limited its losses to 6.1 percent compared with May 2008, a statement said. Volkswagen's high-end auto brand, therefore continued to fare better than its rivals, but the result was still a deterioration from its fall of 5.6 percent in April.
For the first five months of 2009, BMW delivered 487,906 vehicles, or 21.1 percent fewer than in the same period of 2008. "I am globally optimistic concerning an improvement in our sales throughout the year," BMW sales director Ian Robertson said in a statement.
Mercedes-Benz sold 433,100 cars, which was also a drop of 21.1 percent.
Audi sold 374,350 cars, for a more modest decline of 12.1 percent.
At Mercedes, the launch of the E Class limousines has been a success, while sales of A and B Class cars have remained essentially stable on the year.
Meanwhile, the German Economy Ministry revised its figure for March industrial orders higher to a rise of 3.7 percent, the first increase in six months, and added that April orders had stayed at the same level.
The figures demonstrated a "noticeable improvement in the medium-term perspective" for German industries, according to a ministry statement.
Germany's €2,500 ($3,500) car scrapping bonus has underpinned the sales of small cars in particular, with new car registrations jumping by 40 percent in May, according to data released by the auto federation VDA.
More powerful, expensive cars such as those sold by Audi, BMW and Mercedes have not really benefitted from the government's plan however.