Which banks are at risk?
This is the billion-euro question.
Banking analysts are forecasting 10-14 will not make it – with "unlisted German, smaller Italian, Portuguese, Greek and eastern European banks" the biggest concern by geography, according to analysts at Berenberg.
Read MoreHow many European banks would pass U.S. stress tests?
Those most frequently mentioned as in danger include Ireland's Permanent TSB and Austria's Volksbanken, both of which have been bailed out by their respective governments already. HSH Nordbank, a German Landesbank which has a large shipping business, is also at risk if there is a writedown of its shipping assets. Some Dutch banks' property lending portfolios are also a cause for concern, according to credit analysts at Lloyds.
Spain's Banco Popular Espanol, Germany's Commerzbank, and Unicredit, Italy's largest bank by assets, are also in a difficult position, although opinion is divided on whether they will make it through the tests. Commerzbank and Unicredit have been selling off riskier assets this year ahead of the tests.