Volkswagen’s board of management has released a statement that current CEO Dr. Bernd Pischetsrieder (inset) will step down at the end of the year to be replaced by Audi's chief executive, Martin Winterkorn (pictured above).

The move is sudden because it comes only six months after the supervisory board unanimously voted to extend Pischetsrieder's contract until April 2012.

A supervisory board source said officials had agreed not to discuss why Pischetsrieder was leaving, but told Reuters that VW would offer him a new function within the group, possibly for “special assignments.” Rumors suggest that VW’s Chairman, Ferdinand Piech, had a hand in the move as his family controls Porsche, who is Volkswagen’s largest shareholder.

Needless to say, this issue remains unresolved and we’ll be covering it in detail as more information emerges.