Former IMF chief Rodrigo Rato stands trial today accused of overseeing a "corrupt system" that helped him and other executives misuse funds on hotels, parties and luxury shopping when he was a Spanish bank boss.Uncovered in 2013 by a journalist who saw a hacked email alluding to "black credit cards," the case threatens to land the former economy minister and onetime star of the ruling conservative Popular Party (PP) in jail and with a hefty fine. It is also another thorn in the PP's side after repeated failed attempts to form a government following two inconclusive elections, due to a lack of support that is in large part due to corruption scandals sullying the party.Rato will stand trial with 65 other former executives and board members at Caja Madrid and Bankia, whose near-collapse sparked an EU bailout of Spain's financial sector. They are accused of having paid for personal expenses with credit cards put at their disposal by both banks, without ever justifying them or declaring them to tax authorities.