Former New Jersey Gov. Jon Corzine stepped down Friday from his position as head of the brokerage firm MF Global.

His resignation came in the midst of an FBI investigation into $600 million of missing customer money.

The firm declared bankruptcy this week after Corzine's risky bets on European debt backfired.

Regulators said MF Global moved the missing money out of client accounts as the company started to slide towards bankruptcy.

Corzine said his resignation is voluntary.

He declined a $12.1 million severance package.