Iowa Lottery spokeswoman Mary Neubauer said sales were strong over the holiday week for Saturday's drawing, which was estimated at $325 million before the numbers were picked. That was the fourth-largest jackpot in the game's history.
Neubauer says the jackpot for Wednesday's drawing could go even higher than the estimated $425 million because sales pick up in the days before record drawings.
The previous top Powerball prize was $365 million, won in 2006 by a ConAgra Foods Workers in Lincoln, Neb.
The Powerball numbers for Saturday were 22-32-37-44-50, and the Powerball was 34.