Traditional sportsbooks set prices and take the other side of your bet. Exchanges and prediction markets work differently: they match you with other people who want the opposite position, and charge a fee or commission instead of building a margin into every price. That difference matters both for where you bet and for how you estimate fair odds.
How a betting exchange works
On an exchange, users post offers ("I will back Team A at +110") and others accept them. The exchange takes a commission, typically a small percentage of net winnings or a per-contract fee, instead of a vig.
Advantages for bettors:
- Tighter prices on liquid markets (often close to fair)
- Winners are not limited the same way, since the exchange is not taking the risk
- Prices move with the crowd's money, including professionals
Downsides:
- Liquidity can be thin on smaller markets
- Fees must be included in your EV math
- Fewer promotions
Prediction markets and event contracts
In the US, some platforms offer sports outcomes as event contracts that pay $1 if an outcome happens. A contract trading at 58¢ implies about a 58% chance. These platforms operate under federal commodities regulation (the CFTC) rather than state gaming licenses, which has led to legal disputes with some states. Availability and legal status vary and continue to change, so check what applies where you live.
Several sports-focused exchanges also operate under similar federal frameworks, offering peer-to-peer sports markets in many states.
Converting exchange prices to odds
- Contract price (in cents) ≈ implied probability
- 58¢ → 58% → fair American odds about −138
- Account for fees: a fee on winnings lowers your effective payout
Example: buy at 58¢ with a 2¢ fee per contract if it wins. Your effective win is 40¢ on 58¢ risked → decimal ≈ 1.69 → about −145.
Why sharp bettors watch exchanges
Liquid exchange and prediction-market prices reflect real money from many participants with no built-in vig, which makes them useful reference prices for fair lines, alongside sharp sportsbooks. (Fair odds explained · What is a sharp sportsbook?.)
OddsHype includes several exchanges and prediction markets among its sharp sources (with lower weights than the sharpest books, and only when quotes are fresh), and shows exchanges as bettable options only in states where they are not blocked.
Exchanges vs sportsbooks: when to use which
| Sportsbook | Exchange / prediction market | |
|---|---|---|
| Promos | Many | Few |
| Margin | Built into price | Commission/fee |
| Limits for winners | Often | Less of an issue |
| Market depth | Deep on everything | Deep on big markets, thin on niche |
| Props | Huge menus | Growing, more limited |
Many sharp bettors use both: sportsbooks for promos and soft prices, exchanges for fair prices and volume.
Frequently asked questions
Are betting exchanges legal in the US?
Some exchanges and prediction markets operate under federal commodities regulation, but legal status varies and has been challenged in some states. Check the rules where you are.
How do prediction market prices convert to odds?
A contract's price in cents approximates its implied probability; 60¢ ≈ 60% ≈ −150, before fees.
Do exchanges limit winning bettors?
Exchanges match users against each other rather than taking the risk themselves, so they generally do not need to limit winners the way sportsbooks do.