The euro area's biggest banks will be asked to earmark funds equivalent to more than twice their minimum capital requirements to make sure a possible emergency doesn't cost taxpayers, according to Elke Koenig, head of the Single Resolution Board.

The Brussels-based SRB, the resolution authority for 142 banks including Deutsche Bank AG and BNP Paribas SA, will use the minimum capital requirement set by the European Central Bank as a proxy for funds that would be needed to absorb losses and allow recapitalization in a crisis, Koenig said in an interview this month. The ECB last year set an average requirement for the highest-quality capital of 9.9% of risk-weighted assets.

Requiring banks to have at least the same amount again in loss-absorbing liabilities will ensure that they can recapitalize themselves quickly after restructuring, Koenig said. This minimum requirement of own funds and eligible liabilities, or MREL, is calculated at the “30,000-foot level,” and more precise levels tailored to each bank will follow after the ECB sets new capital requirements and changes are made to capital, bank-failure and insolvency rules, she said.