25 billions euros has been pumped into Greece's top four banks in recent years. They're all majority-owned by the country's bank rescue fund. Greek bank stocks have also lost almost a third of their value this year - while equities have generally staged a recovery. Why then are U.S. billionaire investor John Paulson - and reportedly several other American hedge funds - ready to invest? Richard Hunter is Head of Equities at Hargreaves Lansdown.