Although the Central Bank has raised the minimum capital standard for Irish banks to 12%, as per the terms of the EU/ IMF bailout agreement, the actual capital that AIB, Bank of Ireland, EBS and Irish Life & Permanent will be required to hold is actually a good bit higher.

AIB, for instance, has to meet a 14% core capital requirement by the end of February 2011. The bank will now have to raise nearly €10bn in additional funds in the next three months to stay within the regulatory guidelines – about double the amount pencilled in under the Central Bank's benchmark capital assessment last March.

Bank of Ireland has a shorter distance to travel, as the Central Bank has determined it will need to hit a target of 12.5%. That comes with a bill of €2.2bn – almost as much as the bank had to raise from its record-breaking fundraising last May. The bank said last week it would raise the money through internal means, existing shareholders and the capital markets, but analysts are assuming the money will come by increasing the state shareholding.

EBS has about €1bn to go to get to 13.5% by its end-of-year deadline. IL&P has until May to put together €243m in fresh capital to reach 12.7%, which executives believe can be done through internal resources alone.

The differing capital levels reflect the expectation by Central Bank officials that certain banks will lose far more on bad loans than others. The additional capital above the 12% mark is seen as a buffer to absorb anticipated provisions.

AIB is obviously perceived as the weakest, while Bank of Ireland is still regarded as the strongest. IL&P is outside Nama and therefore less vulnerable, but some analysts fear its trouble could arise later if the Central Bank is very aggressive in its stress tests of mortgage loan books during the next capital assessment in March.