- Traders at Kalshi and Polymarket wanted their Sam Darnold bets voided after he exited early with an injury, but that’s not how prediction markets operate.
- Prediction markets can’t void trades like sportsbooks can void bets since predictions are peer-to-peer exchanges and don’t have a “house” like state-regulated sportsbooks.
- Contract rules declare player markets settle based on the final stats despite injury or ejection if the player participated in at least one play.
SEATTLE – Player prop markets on Kalshi are riskier than betting at state-regulated sportsbooks because prediction markets won’t void a trade due to injury. Wednesday night’s NFL season opener showed bettors and traders this important difference between predictions and legal sports betting when it comes to voiding bets/trades.
Sam Darnold’s injury on the sixth play of the game last night had fans begging for all his player prop markets to be voided. That’s not how it works with prediction markets, who operate as peer-to-peer exchanges without a house.
Since sportsbooks have a “house”, they can decide when or when not to void a wager. This has led to many operators to offer injury insurance, like BetOnline PlayerProtect, which BetOnline Sportsbook introduced in the NBA Playoffs that refunded parlays and straight bets that lost due to an injury.
Prediction markets don’t do this since they simply facilitate a transaction between buyers and sellers, rather than participating in the transaction themselves.
Kalshi Rules State Their Stance On Player Injury
Kalshi’s rules for their prediction market contracts make it clear that any player prop trades are action, so long as that player plays at least one snap.
Their terms and conditions read:
“If <entity> is a player, the player must participate in at least one play of <game> for markets to settle based on actual statistics. If a player is active but does not participate for at least one play during <game> all Contracts on that player for that <game> will resolve to the last fair price as determined by the Exchange in its sole discretion.”
Their rulebook also states that Kalshi has sole discretion to interpret a Contract’s Terms and Conditions. The kickoff to the 2026 NFL season made it clear that prediction markets handle voiding player props due to injury far differently than sportsbooks.
Kalshi trading volume surpassed $105 million for the NFL’s regular season opener. Last year, it was just $26.7 million so new traders should know the way these markets handle player prop markets.
