"Too-big-to-fail" legislation unveiled yesterday in Washington is needed to rein in the biggest U.S. banks because the Dodd-Frank Act has failed to guard taxpayers against future bailouts, the bill's sponsors said.

The four largest banks — JPMorgan Chase & Co., Bank of America Corp., Citigroup Inc. and Wells Fargo & Co — "are nearly $2 trillion larger than they were" before getting U.S. aid to help them weather the 2008 credit crisis, Senator Sherrod Brown said in a news conference.

"If big banks want to continue risky practices, they should do so with their own assets," said Brown, an Ohio Democrat. "Our bill will ensure a level playing field for all financial institutions by ending the subsidy for Wall Street megabanks and requiring banks to have adequate capital."