Research · Arbitrage betting
Prediction markets vs sportsbooks: how event contracts differ from bets
Prediction markets vs sportsbooks: who sets the price, how contract prices convert to odds, and where federal regulation of sports event contracts stands.
Reviewed by Owen DavidsUpdated Oct 30, 2026Facts checked Oct 30, 2026
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Prediction markets vs sportsbooks differ in who sets the price and who regulates it. On an exchange such as Kalshi, users trade event contracts with each other and prices track the market's estimated probability. A sportsbook quotes its own odds. Event contracts are listed by CFTC-registered entities; sportsbooks are licensed by states.
Prediction markets vs sportsbooks at a glance
| Prediction market (event contracts) | Sportsbook | |
|---|---|---|
| Who sets the price | Users trading with each other | The sportsbook |
| How the price is shown | A probability, in cents | Odds (American, decimal) |
| Regulator | Federal: the CFTC | State gaming regulators |
| Cost to the bettor | Exchange fees | Margin built into the odds |
Kalshi describes its prices as tied directly to the probability of the event, from 0% to 100%, and says it matches buyers and sellers with opposing views; a matched Yes and No together put up $1.[1] In Massachusetts, for example, sportsbooks are licensed and taxed by the Massachusetts Gaming Commission.[4]
Converting contract prices to odds
Before fees, a contract price works like an implied probability:
| Contract price | Implied probability | Decimal odds | American odds |
|---|---|---|---|
| 25¢ | 25% | 4.00 | +300 |
| 40¢ | 40% | 2.50 | +150 |
| 60¢ | 60% | 1.67 | -150 |
| 75¢ | 75% | 1.33 | -300 |
Fees lower the effective payout, so compare after fees.[2] Convert sportsbook prices with the odds converter, and remove a sportsbook's margin with the no-vig calculator before comparing it with a contract price.
Where federal regulation stands
On June 10, 2026, the CFTC published a notice of proposed rulemaking that would amend its Regulation 40.11 and add an Appendix F to Part 40, creating a framework for deciding whether an event contract involves an "enumerated activity" such as gaming and, if so, whether it is contrary to the public interest. The proposal defines statutory terms including "involve" and "gaming." The release notes growth in event contracts, including contracts referencing sporting events.[3]
It's a proposal, not a final rule. How sports event contracts fit with state sports-betting laws is outside what this release settles, and we haven't reviewed the state-by-state position.
Comparing prices across both
The arithmetic for comparing a contract with a sportsbook price, or for an arbitrage across the two, is the same as for two sportsbooks (see Arbitrage betting explained), with two extra checks: fees on the exchange side, and whether both venues settle the event on exactly the same terms.
Frequently asked questions
What is the difference between a prediction market and a sportsbook?
On a prediction market, users trade event contracts with each other and the price reflects their views. A sportsbook quotes its own odds. They also sit under different regulators: event contracts under the federal CFTC, sportsbooks under state regulators.
How do I convert a contract price to betting odds?
Treat the price as a probability: a 40-cent contract implies 40%, which is decimal odds of 2.50 (+150). Fees reduce what you actually receive, so the effective odds are a little shorter.
Are sports event contracts legal?
That's contested. The CFTC proposed a framework in June 2026 for deciding whether contracts involving gaming are contrary to the public interest, and it is a proposal, not a final rule.
Can you arbitrage a prediction market against a sportsbook?
The math is the same as any arbitrage: if the combined implied probabilities across both venues are under 100% after fees, there's an arbitrage. Settlement rules must match exactly, which isn't guaranteed.
Sources
- 1.How are prices determined?, Kalshi Help CenterOfficial vendor documentation · accessed Oct 30, 2026
- 2.Kalshi Fee Schedule (July 2026 update, effective July 7, 2026), KalshiOfficial vendor documentation · accessed Oct 30, 2026
- 3.CFTC Seeks Public Comment on Notice of Proposed Rulemaking Concerning Event Contracts Involving Enumerated Activities (Release 9249-26, June 10, 2026), Commodity Futures Trading CommissionRegulatory publication · accessed Oct 30, 2026
- 4.Revenue (sports wagering licensees and tax rates, updated 10.20.2026), Massachusetts Gaming CommissionRegulatory publication · accessed Oct 30, 2026
About this page
- Editorial review
- Approved by Owen Davids on Oct 30, 2026
- AI assistance
- Drafted with AI assistance. Facts, sources and conclusions were checked by a human editor before publication.
- Facts last checked
- Oct 30, 2026
How we research and label evidence: our methodology.
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