DES MOINES, Iowa (AP) — Lottery officials say the next Mega Millions prize could surpass last year’s record $656 million jackpot. No one won the $425 million prize on Friday night. And officials Saturday raised the amount to $550 million for Tuesday’s drawing, the fourth-largest in U.S. history. The game’s lead director Paula Otto said Sunday that ticket sales were up by as much as 20 percent in states that reported their weekend numbers. Sales are expected to spike Tuesday.

Otto says lottery officials are in uncharted territory because there’s never been such a large jackpot in December, when tickets sales typically peak. It’s too early to know whether the jackpot will reach a record, but Otto says she expects it will come close.