Porsche’s announcement that it planned to boost its stake in VW beyond the mandatory 30 percent triggering a takeover bid came in the wake of sharp rises in car stocks Friday, with Volkswagen stock surging 13 percent.

This caps a recent more-than 30-per-cent rise in VW shares following signs that the carmaker’s hefty cost-cutting program was starting to produce results and speculation that Porsche was planning a move on Volkswagen.

The big jump in auto shares last week were also fuelled by talk that trans-Atlantic carmaker DaimlerChrysler AG was considering selling off its troubled US Chrysler offshoot.

Earlier this year DaimlerChrysler chief Dieter Zetsche said that “all options” were on the table fuelling speculation about the loss-making Chrysler’s future.

Shares in Stuttgart-based DaimlerChrysler, which also manufactures Mercedes Benz cars, rose 6.6 percent 62.13 euros (82.60 dollars) in Frankfurt Friday amid hectic trading in European car shares that helped pushed leading bourse indexes up by more than two percent.

This was despite DaimlerChrysler dismissing as rumors reports that it had reached a deal to hive off Detroit-based Chrysler following a joint bid from a private equity firm and possibly a Canadian auto supplier Magna International.

DaimlerChrysler’s denial has also failed to dampen market talk that it was keen to resolve the future of its Chrysler’s subsidiary before next month’s stockholders’ meeting in Berlin.

The possibility that DaimlerChrysler might sell off its North American business comes some nine years after Stuttgart-based Daimler and Chrysler agreed to forge their operations in what was billed at the time “a merger of equals.”

Either way, the new sense of upheaval and change surrounding the German car industry comes amid fierce competition in the global auto market.

“Cooperations and alliances are not uncommon even today, but in the not-too-distant future they will be a part of everyday life. Both Porsche and Volkswagen will be prepared for this,” Porsche said outlining its plans for VW.

The prospects of a change of ownership of VW represents the latest round in Europe’s biggest carmaker’s recent turbulent corporate history, which included last year’s dramatic departure of the German-based group’s chief executive and a sex-and-bribery scandal.

This coincided with a push by Porsche to build up a 27.3 percent stake in VW’s. Now Porsche said on the weekend that it planned to raise its stake in VW up to 31 percent.

Under German law, building a stake above 30 percent requires a company to launch a takeover bid.

“Porsche is firmly convinced that a closer bond with VW through an increase of the stake to more than 30 percent of the Volkswagen ordinary shares will produce benefits for both partners without diluting or indeed endangering the identity of Porsche,” it said in a statement.

Up until now, Porsche has insisted that it had no plans to raise its stake to 30 percent or more. And on Saturday Porsche spokesman Anton Hunger said: “We are not aiming for a majority.”

Nevertheless, Porsche, which is controlled by the family of VW chairman and former chief Austrian-born Ferdinard Piech, had been widely expected to push to strengthen its influence on Volkswagen.

“VW will become an Austrian family company,” said German car industry analyst Ferdinand Dudenhoeffer.

At the same time, Volkswagen’s second-biggest stakeholder, the German state of Lower Saxony, welcomed the Porsche move.

“In the light of the worldwide challenges it is a blessing for VW to have the state of Lower Saxony and Porsche as two reliable partners,” said Lower Saxony Premier Christian Wulff.

Porsche said its decision to raise its stake beyond 30 percent also came in the wake of moves to dismantle or water down the so-called Volkswagen Law, which limits investors from taking a controlling interest in the carmaker.

Already new VW’s chief Martin Winterkorn, the former head of Volkswagen’s luxury offshoot, Audi, has moved to make his mark on the group by unveiling details of a major shakeout in Volkswagen, including a management restructuring.

Apart from its mass brands - VW, Skoda and Seat - Volkswagen’s stable of cars also include premium brands - Bentley, Bugatti and Lamborghini.