Fourteen European banks will have to scrape together billions of euros in new funds to prop up their deposits, after failing stress tests set by regulators.
The European Banking Authority (EBA) says another 10 banks also failed the stress tests of their finances, but have already taken steps to bolster their balance sheets.
The review was based on the banks' financial health at the end of 2013.
The health check was carried out by the EBA to determine whether they could withstand another financial crisis.
The list of 14 includes four Italian banks, two Greek banks, two Belgian banks and two Slovenian banks.
The worst affected was Italian bank Monte dei Paschi, which had a capital shortfall of €2.1 billion.
The BBC reports concerns about banks were a central element in the eurozone financial crisis and in some countries their weakness remains a factor holding back economic growth.
Four UK banks were subjected to the test; Royal Bank of Scotland, HSBC, Lloyds Banking Group and Barclays. None failed, though Lloyds passed narrowly.