Early this morning (GMT) the BBC News released in their on line version that Porsche is to increase by 3,7% its stake in VW. As the piece suggests at Porsche they're not after a full take over just for a total stake of up to 31%. Otherwise and according to the German law P would have to bid for all of VW.

More info here

http://news.bbc.co.uk/1/hi/business/6492715.stm