Several lotto players in Philadelphia, New York and and other states won $1 to $2.5 million for choosing five numbers correctly but getting the Powerball wrong.
The $400 million prize is Powerball's fourth biggest jackpot in its history. A Florida woman won the largest ever jackpot back in May with $590.5 million.
Larger prizes usually attract more ticket buyers, so organizers expect the jackpot to get even bigger before Wednesday's drawing.
"It’s all based on sales because that’s what feeds the jackpot,” a New York Lottery rep told NBC News.