A co-sponsor of far-reaching Wall Street reform legislation concedes it was a "mistake" to set the limit too low on banks that would get "extra supervision" in the wake of the 2008 financial crisis.

In an interview with radio host John Catsimatidis on Sunday's "The Cats Roundtable," former Massachusetts Democratic Rep. Barney Frank talked about the pros and cons of the 2012 reform measure the Dodd-Frank Act.

"We put in [Dodd-Frank] that banks got the extra supervision if they were $50 billion," he said. "That was a mistake. We should have made it much higher $125 billion or more, and indexed it."

Frank, an expert on bank stocks and now a board member of the New York-based Signature Bank, also said he supports relaxing federal regulations on "smaller and medium-size banks."

And he predicted higher interest rates and bigger deficits under President-elect Donald Trump.

• Trump's Transition Team Pledges to Reform Banking Laws
• A Post-Trump SEC Could Shake up Current Policy