Italian bourse CEO says there are 'colossal' short positions on Italy in advance of referendum

``Big international investors are holding huge short positions on Italian assets, the CEO of the Italian exchange said on Tuesday, days before the country holds a referendum on constitutional reform that could unseat Prime Minister Matteo Renzi... Opinion polls conducted until a blackout period began last week showed the "no" vote comfortably in the lead, raising concerns of a political crisis and fueling market volatility.''