A European Union law up for a vote on Monday will only fully shield taxpayers from bailing out troubled banks if there is a global framework as well, a top UK regulator said on Monday.
Bank of England Deputy Governor Paul Tucker said the EU law on bank recovery and resolution would be a milestone towards a global system and help convince markets that governments were no longer willing to rescue "too big to fail" lenders.
Since governments had to shore up banks during the 2007-09 financial crisis, regulators have wanted to stop markets assuming big banks would not be allowed to go out of business.
The European Parliament's economic affairs committee holds a first vote in Strasbourg, France at 1830 GMT. It has joint say with EU states on the law that gives regulators powers to impose losses on creditors, replace management and take other steps when a bank gets into trouble.
In a speech in the Netherlands, Tucker said there had been "marked convergence" recently on a global approach to winding down banks which typically have operations in many countries.
But more political impetus was needed as it would still be a "nightmare" to wind down a big bank, he added.
The EU law will have powers to force big banks to hold a cushion of bonds that can be converted into equity to shore itself up without taxpayer cash. Tucker said a discussion on such a cushion at the global level was still needed.
This "loss-absorbing" cushion should be equivalent to the amount of capital a lender holds in its capital buffer with an added margin for safety, he said.
The biggest banks will have to hold a core capital cushion of up to 9.5 percent by 2019 though many are already at or above this level due to market and supervisory pressures.
Banks should not hold large amounts of bonds of other banks and nor should insurers hold chunks of bank debt, Tucker said.
He backed EU consensus that depositors with up to 100,000 euros ($128,000) in their account should not suffer losses in a bail out, a step Monday's vote is expected to confirm.
There was also case for some uninsured depositors, such as small businesses and charities to be shielded also, he added.
EU finance ministers agreed last week that large, uninsured depositors should be subject to losses and the vote on Monday is expected to back this, on condition that any losses are imposed only after the bank's bondholders have been tapped first.
Even with an EU system in place, many banks will still need to restructure themselves to be wound up easily, Tucker said. The EU's financial services chief Michel Barnier will say in the autumn whether big banks should be broken up.