Data on vehicles sold by the companies during the first six months of 2015 show the German automaker nudged out its Japanese rival to claim the top spot.

Volkswagen (VLKAF) sold 5.04 million vehicles from January to June, a slight dip from a year earlier. That compares to 5.02 million sold by Toyota (TM) over the same period. Group sales dropped 1.5% due to a weaker performance by its Toyota and Daihatsu brands.

Automakers are being challenged by softening conditions in markets like China and Russia, and Volkswagen is cautious about the outlook.

The carmaker, which also owns the Audi (AUDVF) and Porsche (POAHY) brands, described its performance so far this year as "satisfactory" in a difficult environment.

-CNN