Seven years after the collapse of Lehman Brothers jolted the global economy, the world's biggest banks may need to raise as much as US$1.2 trillion to meet new rules laid down by financial regulators.

After years of work, the Financial Stability Board (FSB), created by the Group of 20 nations in the aftermath of the crisis, published its plan for making sure giant lenders can be wound down and recapitalized in an orderly way, without taxpayer bailouts.

Under the rule for total loss-absorbing capacity, or TLAC, most systemically important banks must have liabilities and instruments “readily available for bail in” equivalent to at least 16 percent of risk-weighted assets in 2019, rising to 18 percent in 2022, the FSB said on Monday. A leverage ratio requirement will also be imposed, rising from 6 percent initially to 6.75 percent. The banks' shortfall under the 18 percent measure ranges from 457 billion euros to 1.1 trillion euros ($1.2 trillion), depending on the instruments considered, according to the FSB.