The U.S. futures regulator approved on Monday a rule that puts tighter limits on how brokerage firms can use customer funds, a measure that the now-bankrupt MF Global had encouraged the agency to delay.

The measure was finalized by the Commodity Futures Trading Commission by a 5-0 vote. The rule was initially proposed by the CFTC in October 2010.

The push to finalize the rule gained momentum after MF Global's collapse. The firm filed for bankruptcy on October 31 after investors got spooked by its large bets on European sovereign debt. Regulators are still searching for hundreds of millions of dollars in missing customer money.

(Reporting by Christopher Doering)