BERLIN, June 14 (AFP): Qatar is ready to acquire at least a 25-per cent stake in German luxury sportscar maker Porsche, heavily in debt after increasing its shares in Volkswagen, German media reported.

"The emirate of Qatar and its advisor Credit Suisse on June 8 finished the preliminary examination of Porsche's books," the German news weekly Der Spiegel said in an article to appear in Monday's edition.

Ferdinand Piech, a co-owner of Porsche and former Volkswagen boss, does not have enough backing to turn down Qatar, the weekly said.