Platforms
Polymarket vs traditional sportsbooks
Sports prediction markets and traditional sportsbooks look similar but work very differently. Spreads, payouts, and house edge all favor prediction markets — sometimes dramatically.
If you bet on sports, you've probably used FanDuel, DraftKings, or another traditional sportsbook. The vibe of betting on Polymarket or Kalshi feels similar — pick a side, put money on it, win or lose — but the underlying mechanics are different in ways that affect your actual returns.
No house edge
Sportsbooks make money by setting odds where both sides combined add up to more than 100% — typically 105–110%. That extra 5–10% is the "vig" or "juice", and it's how the house guarantees a profit regardless of which side wins.
Prediction markets are peer-to-peer. The "Yes" and "No" prices add up to exactly $1.00 because shares are fully collateralized. The platform takes a small fee on transactions but doesn't bake in a house edge. You're betting against other traders, not against the venue.
On a popular game with -110/-110 sportsbook odds, the implied probabilities sum to about 105%. The same game on a prediction market sums to 100%. Over hundreds of bets, that 5% difference compounds into significant savings.
Liquidity is different
A sportsbook always has someone to bet against — the book itself. It always offers a price. A prediction market only has prices when other traders are willing to make them. On thinly traded games, you'll see wider spreads and worse fills.
For major events (Super Bowl, World Cup, NBA Finals), liquidity on Polymarket and Kalshi is excellent. For smaller markets, sportsbooks may give you better execution despite the vig.
Resolution and disputes
Sportsbooks have well-defined rules about when and how bets settle. Prediction markets do too, but they're newer and edge cases occasionally surface. We recommend reading how markets resolve before sizing up on contested or weather-affected events.
You can exit before resolution
On a sportsbook, if you bet $100 on Team A pre-game and Team A jumps out to a 21–0 lead, you're stuck holding the ticket until game end (unless your sportsbook offers cash-out, which is usually heavily discounted from fair value).
On a prediction market, you can sell your position at any time at the current market price. Team A goes up 21–0? The "Yes" price might rocket from 0.55 to 0.85, and you can sell at 0.85 to lock in 30 cents of profit per share. This is a fundamentally different product.
When a sportsbook is still better
- Live betting: Sportsbooks have invested heavily in live odds during games. Prediction markets exist but aren't as deep.
- Parlays and exotic bets: Multi-leg parlays, prop bets, and player performance bets are sportsbook native. Prediction markets focus on game outcomes.
- Promo bonuses: New-customer bonuses on sportsbooks can be worth hundreds. Prediction markets don't typically offer them.
- Speed: A sportsbook never refuses your bet. A prediction market might have no order on the other side at the moment you want to act.
For serious sports bettors
Hold both an account at a major sportsbook and one on Kalshi or Polymarket. For positions you want to take and hold to resolution, the prediction market is usually cheaper. For situational, in-play, or exotic bets, the sportsbook still wins.