That is the claim of Norbert Haug, who is in charge of Mercedes' forays in both F1 and the premier German touring car category.
It had been suggested that BMW might turn to the more affordable DTM championship in 2010, after leaving formula one.
But Haug told the German newspaper Bild that Audi and Mercedes are to remain the only manufacturers in DTM next year.
"Next year there will be no other manufacturers," he said.
It is hoped that new rules for DTM in 2011 will entice more car manufacturers to join the series.