(Bloomberg) - Volkswagen AG's former chief executive officer Martin Winterkorn will leave his post running the company's biggest shareholder at the end of the month, cutting another of his ties with the carmaker amid an investigation into cheating on emissions tests.

VW Chairman Hans Dieter Poetsch, who already sits on the Porsche Automobil Holding SE board, will take over for Winterkorn on Nov 1, the Stuttgart-based company said in a statement on Saturday (Oct 17).

The holding company, controlled by the Porsche and Piech families, owns more than half of VW's voting shares.

"It's a good sign but it comes very late," said Ferdinand Dudenhoeffer, director of the Center for Automotive Research at the University of Duisburg-Essen. "Anything else would have been unimaginable."

Talks are underway for Winterkorn to leave his remaining posts as chairman of VW's publicly traded Audi brand and the group's truck holding company, said the people, who asked not to be identified because the discussions are private.

Winterkorn resigned as Volkswagen CEO in September after the German carmaker admitted to cheating on US emissions tests.

Fallout from the disclosure has since spread to encompass as many as 11 million cars around the world. Cleaning up the mess will cost much more than the 6.5 billion euros (S$10.2 billion) Volkswagen already set aside for the task, Winterkorn's replacement as CEO, Matthias Mueller, has said.

Winterkorn took the position of Porsche SE CEO in 2009, shortly after the company's planned takeover of Volkswagen failed because of ballooning debt.

Working with then-Chairman Ferdinand Piech, he helped arrange a fix that gave Volkswagen the Porsche sports-car brand and solidified the families' control over the carmaking group via the holding company.

Winterkorn remains chairman of VW's publicly traded Audi AG unit as well as the group's truck holding company.