The Super Bowl is the biggest sports-betting event of the year, with Americans expected to set a record by wagering more than $1.5 billion on the big game.

Now, for the first time, nearly everyone in the U.S. will be able to get in on the action. That’s thanks to a rivalry as bitter as any on the field.

Prediction-market companies Polymarket and Kalshi are challenging FanDuel and DraftKings-1.54% who popularized and dominated online sports betting over the past eight years. Prediction markets have used a legal loophole that permits wagering on sports outcomes everywhere.

California, Texas and nine other states haven’t legalized sports betting. But prediction markets—which are regulated federall, allow a way in.

The American Gaming Association estimates people wagered $35 billion on the NFL alone and nearly $150 billion across all sports in 2024. Numbers for 2025 are expected to be higher. Americans legally bet a record $1.39 billion on the Super Bowl last year, and that’s likely to be broken this year.