What a difference a year makes. In 2012, it took until January 31 for a Southern European bank to issue senior unsecured bonds — and then it was an 18-month deal.

This year, Spain's Banco Bilbao Vizcaya Argentaria reopened the market globally on January 3, selling €1.5bn ($1.98bn) of five-year bonds-and paid less than the Spanish government to do so. That is encouraging news for Europe's banks, but also a sign of investors' increasing hunger for yield.