SACRAMENTO, Calif.—The identity of one of two jackpot winners of the near-record Mega Millions lottery drawing remains unknown.

The California Lottery said in a statement Thursday afternoon that the person who had purchased a winning ticket at a gift shop in San Jose had not come forward to claim their prize, now revised up to a whopping $648 million. The name of a second winner in Georgia has already been announced.

Split between the two tickets, the lottery commission said, the jackpot comes to a total of $324 million per winner. If the winners choose to take their winnings as a lump sum, they would receive $173.8 million before taxes.

The winner has one year from the date of the drawing to claim the prize.