Prediction Market vs. Sportsbook

On a Prediction Market, the Contract Price is set by traders through an Order Book or Automated Market Maker, reflecting the crowd's collective Implied Probability. The platform earns Trading Fees and never holds a position. On a sportsbook, the oddsmaker sets lines that include a built-in Vig -- typically 4-8% -- ensuring the house profits over time regardless of outcomes. This structural edge means sportsbook bettors face a negative Expected Value on every wager by design. Prediction market traders, by contrast, can have positive expected value if they identify Mispricing relative to true probabilities. Profitable prediction market traders are never throttled or banned the way sharp bettors often are at sportsbooks, since the platform benefits from their Liquidity provision.

In the United States, prediction markets like Kalshi operate as CFTC-Regulated Exchange venues under federal commodity law, making them legal in all 50 states. Sportsbooks operate under state gambling licenses and are unavailable in many states. Geofencing restricts access to decentralized platforms like Polymarket for U.S. users, though regulated U.S. access resumed in late 2025. Prediction markets also differ in event scope: Kalshi lists contracts on Federal Reserve decisions, inflation data, hurricanes, and even box office earnings -- topics no sportsbook covers. Trading flexibility is another distinction: prediction market positions can be sold before Market Expiry at prevailing Market Price levels, giving traders more control than the fixed-odds wager model used by sportsbooks.