WASHINGTON — Declaring that “the time is now” to break up the largest banks, Sen. Bernie Sanders, I-Vt., unveiled a bill Wednesday that would cap a financial institution’s total exposure at 3% of the nation’s GDP.

Firms exceeding that cap would be unwound. A summary of the bill said it would result in the breakup of the six largest financial institutions, which currently have a combined exposure of 68% of GDP.

“Today, the four largest financial institutions in this country are on average 80% larger than they were before we bailed them out,” Sanders, a 2016 presidential contender, said in an online video to unveil the bill. He was joined by Rep. Brad Sherman, D-Calif., who will introduce a companion bill in the House.

The six institutions exceeding the cap, according to the summary, are JPMorgan Chase, Citigroup, Wells Fargo, Goldman Sachs, Bank of America and Morgan Stanley. The bill would also require insurance companies and other nonbanks with more than $50 billion of assets to report their total exposures to regulators.

Companies exceeding the 3% cap would have two years to undergo a restructuring. A breakup would be overseen by the Federal Reserve Board’s vice chair of supervision, or the Fed chair in the case that no vice chair is appointed.

While the bill would not impact credit unions, the movement -- and CU trade groups in particular -- have spent much of the last decade telling regulators and lawmakers that CUs were being punished for the actions of big banks that led to the financial crisis and recession, while credit unions did not engage in risky or abusive practices many for-profit institutions took part in.

The National Association of Federally-Insured Credit Unions last month released a white paper calling for a modernized version of the Glass-Steagall Act, and while NAFCU CEO Dan Berger stopped short of calling for the break up of big banks, he said that decision should be left up to Congress.

Carrie Hunt, EVP and general counsel at NAFCU, said the trade group had not yet taken a formal position on Sanders’ plan and would have to study it closely.

“How we address too big to fail is a complex issue,” she said. “We certainly don’t want anything to disrupt the overarching economy that the United States has, in particular as it relates to the international arena. At the same time, we still think there is a huge threat with too big to fail, and if you were to look at some of those graphs and charts in our Glass-Steagall white paper, you’d see just how concentrated [the United States is] in some of those big financial institutions.”