US money market funds have increased their exposure to eurozone banks, in the latest sign of returning confidence in the stability of Europe's monetary union.

Exposure to eurozone banks of US prime money market funds at the end of September was 16 percent higher on a dollar basis than a month earlier, according to Fitch Ratings. The third consecutive monthly rise followed a pledge in late July by Mario Draghi, European Central Bank president, to do "whatever it takes" to preserve the euro's integrity.