Someone filled out a winning Powerball ticket at this Circle K in Riverside, Calif., on Sept. 18, 2013.
Two Powerball tickets worth $1.7 million were sold in Southern California, but no one has come forward to claim the prizes.
Two tickets matched five numbers, meaning two people are about $900,000 richer.
One ticket was sold at an Arco gas station, at 9600 S. Avalon Blvd., in Los Angeles. The other ticket was sold at a Riverside Circle K, at 6908 Indiana Ave.
The news comes as officials announced that one Powerball ticket purchased at central South Carolina matched all six numbers in the latest drawing for Wednesday's estimated $400 million jackpot.
But as of Thursday morning, no one had come forward to claim the gigantic jackpot. Lottery Executive Director Paula Harper Bethea said winners do not have to come forward publicly.
"There’s somebody out there who’s $399.4 million richer," Bethea said at a news conference Thursday morning at the Murphy USA station in Lexington where the ticket was sold. "We don’t know who they are."
It's the largest Powerball winning ticket sold in South Carolina and the fourth largest in the history of the game.
The numbers from Wednesday's drawing were: 7 - 10 - 22 - 32 - 35 - with the Powerball of 19.
The jackpot's actual value is $399.4 million, with a direct cash option of $233 million. The winner has 180 days to come forward and must bring in the ticket to the South Carolina offices in Columbia.
Powerball is played in 43 states, Washington, D.C., and the Virgin Islands. Tickets cost $2 each.
Back in May, a record $590.5-million winning Powerball ticket was sold in a Zephyrhills, Fla., supermarket to 84-year-old Gloria MacKenzie. She opted for a $371 million lump sum payment.
The largest recent Powerball jackpot was $448 million on Aug. 7. It was divided among the holders of two winning tickets in New Jersey and one in Minneapolis. Six members in an office poll who had been afflicted by superstorm Sandy were among the winners in that drawing.
NBC Wire Services contributed to this report.