A report commissioned by Volkswagen suggests Ferdinand Piech should step down as supervisory board chairman, a source familiar with the matter told Reuters, though he added this may not be the final word.

The study by investment bank JP Morgan also found that representatives of Porsche, that has emerged as VW’s biggest shareholder, should not sit on VW’s board, to avoid potential conflicts of interest, the source told the news agency, confirming media reports.

“This is not wrong but it is hard to say that this is the full truth,” the source, who spoke on condition of anonymity, told Reuters, adding: “The picture may become richer. There may be more pieces of the puzzle to come.”

He reportedly said a contract being drawn up by VW and Porsche to spell out their business relationship could resolve conflict issues and noted it was up to shareholders to elect VW board members.

Reuters noted that the issue is whether Porsche’s role as a major VW investor with around a fifth of the voting rights in Europe’s biggest car maker presents unacceptable influence over a company that is also its business partner and competitor.

Piech’s family and the Porsche clan own all the voting rights to Porsche, on whose supervisory board Piech also sits, the report said.

The news agency added that VW chief executive Bernd Pischetsrieder told analysts that VW would remain independent from Porsche, would reserve the right to enter into partnerships with other car makers such as DaimlerChrysler and, to assuage fears of potential conflicts of interest with Porsche on its supervisory board, planned to introduce a new subcommittee to ensure that corporate governance standards were enforced.