Last week, Mr. Trump signed into law a bipartisan bill that will free thousands of small and medium-size banks from the Dodd-Frank law, and on May 21, he signed a law rescinding a consumer rule aimed at preventing discrimination by auto lenders. The Fed and the Office of the Comptroller of the Currency recently proposed easing limits on how much the largest banks can borrow and the Fed also proposed changes to the stress tests that banks must undergo each year to determine whether they can withstand an economic downturn.

Mr. Trump’s acting director of the Consumer Financial Protection Bureau, Mick Mulvaney, has also engaged in a rapid series of regulatory changes since November, including halting new investigations, freezing new hires and preventing the agency from collecting certain data from banks.

Regulators said on Wednesday that the primary intent of the Volcker Rule would remain intact and that banks would not be allowed to return to the wild days of proprietary trading, when traders made big bets with the bank’s money and sometimes lost huge sums. But they said the rule needed to be simplified so that banks could more easily comply with it and Washington could adequately enforce it.

“The proposal will address some of the uncertainty and complexity that now make it difficult for firms to know how best to comply, and for supervisors to know that they are in compliance,” the Fed chairman, Jerome H. Powell, said at a board of governors meeting. “Our goal is to replace overly complex and inefficient requirements with a more streamlined set of requirements.”

The Volcker Rule, while not the most significant postcrisis regulation, is arguably the most recognizable. It was included at the behest of Paul Volcker, a former Fed chairman who warned that Wall Street was recklessly gambling with house money. On Wednesday, Mr. Volcker, now the chairman of a nonpartisan think tank called the Volcker Alliance, welcomed efforts to simplify compliance with the rule but said in a statement, “What is critical is that simplification not undermine the core principle at stake — that taxpayer-supported banking groups, of any size, not participate in proprietary trading at odds with the basic public and customers’ interests.”