Qatar may buy VW or Porsche stake
Porsche owns more than 50% of Volkswagen
The Gulf state of Qatar is considering buying a big stake in either Volkswagen or its majority owner Porsche.
VW said in a statement that it would welcome the investment because it would speed up its merger with Porsche.
The Qatar Investment Authority (QIA) is in advanced talks about buying up to 25% of Porsche, according to a report in the Financial Times.
Porsche owns more than 50% of VW, but suspended attempts to buy a controlling stake of 75% when it ran out of money.
Porsche took on 9bn euros ($12.2bn; £8bn) of debt to increase its stake in VW, but that debt is now creating tension between the two companies.
Had Porsche succeeded in controlling VW, it could have used the larger company's financial muscle to refinance its debt, but having failed to do so, it has been forced to apply to the German government for an emergency 1.75bn euro emergency loan.
VW and Porsche own stakes in each other through a complicated family history that unites the two carmakers and the German state of Lower Saxony, which holds a 20% stake in VW and can block strategic decisions under the "VW law".
VW chairman Ferdinand Piech is the grandson of Ferdinand Porsche, the founder of the car company that bears his name. He has a seat on Porsche's board.
Mr Piech strained relations recently by saying that Porsche had to trim its debt if the merger was to move ahead.
Porsche's holding company is chaired by Mr Piech's cousin, Wolfgang Porsche.
Qatar's interest in Porsche follows the purchase in March by Aabar, an Abu Dhabi state investment fund, of a 9.1% stake in German carmaker Daimler for 1.95bn euros.
Daimler and Aabar said they would work together on the development of electric vehicles and establish a training centre in Abu Dhabi for the auto industry.
An investment by Qatar into Porsche could involve a similar agreement.
Among the more high profile stakes held by the Gulf State of Qatar are a 27% stake in Sainsbury's and 15% of the London Stock Exchange.