But as these three banks aren't publicly traded, the Spanish government said it would give the holders of their newly created ordinary shares the option of selling them to the country's deposit guarantee fund.

WSJ: Spain Brings the Pain to Bank Investors

Many argue the euro zone's survival now depends on rapid moves towards full political and fiscal union, with a single European banking supervisor, a common deposit guarantee fund and resolution fund, a central European treasury operation and common issuance of bonds a formidably high hurdle.

WSJ: Nobel Prize for EU an Inspired Decision

They would also like to see a joint bank deposit guarantee scheme and a fund for winding down banks.

BBC: Europe: Condition acute for eurozone

However, German Finance Minister Wolfgang Schaeuble said he and the International Monetary Fund had been in favour of "respecting the deposit guarantee for accounts up to 100, 000" euros.

BBC: Cyprus parliament vote on bailout postponed