The Volcker Rule could have unforeseen consequences, but it's needed to protect consumers and the economy from banks making "wild flyer bets that are just for the house," outgoing CFTC Commissioner Bart Chilton told CNBC before casting his vote.
The Commodities Futures Trading Commission, the Federal Reserve, the Securities and Exchange Commission, and two other U.S. agencies are expected to approve the rule Tuesday.
If approved, the final version would become effective April 1, 2014, according to a joint press release issued Tuesday morning, with the Fed extending the conformance period until July 21, 2015.
Banks have been fighting this part of the Dodd-Frank Wall Street reforms since the law passed in 2010.
(Read more: Volcker Rule, curbing bank risk-taking, nears vote)