CME Group Inc. said trading would be open from 5 p.m. until 2 p.m. and closed only for the three hours in the late afternoon.
The Chicago Sun-Times reported Saturday that CME is going from 17 hours per day to 21 hours to stave off a rivalry with the Intercontinental Exchange.
Convenience aside, the new hours will eliminate a two-hour delay that used to allow traders to digest early morning U.S. Department of Agriculture reports before trading began each day.
Now, without the delay, trading could become more volatile, said Mathew Rees, executive vice president of the futures brokerage R.J. O'Brien & Associates.
It would also give some traders an edge, if they can get their hands on the reports before others do, the newspaper said.