President Trump is considering breaking up big Wall Street banks, by splitting their consumer business from their investment operations.
"I'm looking at that right now," he told Bloomberg television.
US banks were cleared to own High Street banks and investment banking operations in 1999 when the Glass-Steagall Act was repealed.
"There's some people that want to go back to the old system, right? So we're going to look at that," he said.
The repeal of Glass-Steagall was blamed by some for laying the groundwork for the financial crisis in 2007-8.
President Trump expressed support for a "21st-century Glass-Steagall" before the election.
He has also promised to roll back legislation covering the banking sector, including the Dodd-Frank regulations introduced following the financial crisis.
Dodd-Frank was designed in part to protect consumer banking operations from riskier investment banking business.
Banks stocks initially fell before recovering ground.
Earlier US Treasury Secretary, Steve Mnuchin said he believed the American economy could be growing at a rate of three percent within two years, thanks to the administrations proposed tax reforms.
On the campaign trail Trump promised growth of 4% a year. The economy is currently growing at a rate of 0.7%.