Sports Prediction Markets: Odds & Probabilty 🏟️

Are sports event contracts legal?

Yes, but through a different legal framework than sportsbooks. Sports contracts are regulated by the Commodity Futures Trading Commission (CFTC) as derivatives, not by state gaming commissions as gambling. This distinction is why Kalshi can offer sports markets in California and Texas while sportsbooks like BetMGM cannot. It’s also why FanDuel and DraftKings quickly entered the market with an MVP product to capture the demand in states that don’t offer online sports betting.  

How it works legally

Event contracts fall under the Commodity Exchange Act, which gives the CFTC authority to regulate derivatives markets. Platforms like Kalshi operate as Designated Contract Markets (DCMs)—the same regulatory status held by the Chicago Mercantile Exchange. Under federal law, CFTC jurisdiction preempts state gambling regulation for registered exchanges.

Kalshi tested this in court. When the CFTC tried to block election contracts in 2024, a federal judge ruled that event contracts are not “gaming” under federal law. That ruling opened the door for sports contracts in January 2025. A California federal court later upheld this framework against tribal challenges in November 2025.

State challenges

Not everyone agrees with the ruling. More than 30 states have filed amicus briefs supporting state authority over sports event contracts. The question around whether CFTC registration preempts state gambling law remains unresolved and will likely require appellate or Supreme Court review. In response, Kalshi, Crypto.com, Robinhood, Coinbase, and Underdog formed the Coalition for Prediction Markets in December 2025 to defend federal regulation.

Compare sports prediction sites

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Welcome BonusThe promotional bonus offered to new users when signing up with this promo code.	Deposit $10, Get $20 Trading Bonus	Trade $25, Get up to $500	Bonus on Sign-up	Trade $10, Get $10
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Min DepositThe minimum amount you need to deposit to be eligible for the welcome bonus.	$10	$25	$10	$10
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	Get Started Risk Disclaimer Polymarket Risk Disclaimer 18+ Only. Restrictions and eligibility requirements apply. Not available in all jurisdictions. Trading is risky. 100% loss can occur. See polymarket.com/tos for more information. The Polymarket US App serves as an independent software provider and affiliate of Polymarket US and Polymarket Clearing, the CFTC-regulated exchange and clearing organization.	Get Started T&C's apply. Kalshi Terms & Conditions Deposit and trade at least $25 on Kalshi within your first 7 days to claim a bonus of anywhere from $15 to $500. The bonus is available for trade only and is not cashable. Must be used within 7 days. Eligible US states only.	Get Started T&C's apply. FanDuel Terms & Conditions Credited within 72 hours of meeting the requirements. The bonus itself is non-withdrawable, but winnings from bonus-funded trades are immediately withdrawable. If the bonus trade wins, you keep the winnings portion but not the original bonus stake. Must be 18+	Get Started T&C's apply. OG Predictions Terms & Conditions Your first trade must be $10 to qualify for the $10 offer within the first seven days of your account. 18+ only.

Click any promo code to copy it. Terms and conditions apply. Must be 18+ to participate.

How sports contracts differ from sportsbooks

If you’ve used DraftKings Sportsbook or FanDuel Sportsbook, prediction market betting works the same but differently. Here is a quick table to help explain why odds, payouts, and available markets don’t match what you see on a sportsbook.

How the exchange model works

Sportsbooks are basically dealers, or market makers. They set lines, take bets, and profit when bettors lose. If you win consistently, they may limit your account, which is often the complaint with regulated betting.

Prediction markets are exchanges. They match buyers and sellers and take a small cut on each transaction. The platform doesn’t care who wins (or loses), sites charge a fee either way. There’s no incentive to limit winning traders because the platform isn’t on the other side of your position.

What you give up with prediction markets

Sportsbooks offer features that prediction markets currently lack. No platform offers parlays on event contracts yet, though Kalshi has hinted at “new structures” coming. Player props are limited compared to sportsbooks. And the variety of alt lines, teasers, and exotic bets available on DraftKings Sportsbook doesn’t exist in the prediction market format. You won’t receive the promos you’re used to, either. The markets offer sign up bonuses, but these are usually capped at $10-$75.

What you gain with prediction markets

You can trade in and out of positions before the event settles. If you buy Chiefs to win the Super Bowl at $0.25 and the price moves to $0.40, you can sell for a profit without waiting for the game. This makes event contracts function more like stocks than bets. You also won’t get limited for winning.

Here’s a quick tutorial using Kalshi as the example.

How to read sports contract prices

Event contracts trade between $0.01 and $0.99. The price represents the market’s implied probability that the outcome occurs. A $0.65 contract means the market estimates a 65% chance of that outcome.

How payouts work

Every contract settles at either $1.00 (outcome happens) or $0.00 (outcome doesn’t happen). Your profit or loss is the difference between your purchase price and the settlement price.

Example: Seahawks are Yes contract trading at $0.58. You buy 100 contracts for $58. If the Seahawks win, you receive $100 (profit of $42). If they lose, you receive $0 (loss of $58).

Want to run your own numbers?

Our payout calculator shows exactly what you’d win or lose at any contract price and position size. You can also use our P&L calculator to calculate your profit / loss across the major markets.

Converting implied probability to American odds

If you’re used to sportsbook odds, this table shows the equivalent in implied probability which is what you will see at Kalshi:

Probability vs. American vs. Fractional odds:

Use our sports odds calculator to translate between contract prices, implied probability, fractional and American odds.

The spread (how Kalshi and Polymarket make money)

On a sportsbook, vig is built into the odds (-110 on both sides instead of +100). On prediction markets, the equivalent is the spread between Yes and No prices.

Example: Chiefs to win. Yes trading at $0.52. No trading at $0.50. The $0.02 gap is the spread. If you buy Yes at $0.52 and immediately sell at $0.50, you lose $0.02 per contract. Tighter spreads mean more efficient markets.

Platform fees are separate from the spread. Kalshi charges a variable fee based on contract price (highest near $0.50, lowest near $0.01 or $0.99). Polymarket currently charges zero trading fees on its US platform for sports contracts.

What’s your break-even?

Our break-even calculator factors in entry price, fees, and exit scenarios so you know exactly what price you need to sell at to come out ahead.

Types of sports event contracts

Available markets vary by platform. Kalshi and Polymarket offer the widest selection and highest liquidity. DraftKings, Fanatics, and FanDuel launched with more limited offerings.

Liquidity guide: High = tight spreads, easy to enter/exit large positions. Medium = tradeable but wider spreads. Low = thin order books, harder to execute.

NFL, referred to as Pro Football on prediction markets

The NFL generates the most volume across all prediction market apps. Super Bowl markets alone have exceeded $30M in trading volume across the top two apps and we also have Week 1 odds coming out.

NBA, Pro Basketball

The NBA has strong game-by-game volume, particularly on Polymarket where individual games routinely see $1M+ in trading.

NHL / Ice Hockey

This has significantly lower volume than the NFL or NBA markets, but Polymarket offers more game-by-game coverage than all other apps. The NHL became the first major US league to sign licensing deals with prediction markets (Kalshi and Polymarket) in October 2025.

College sports

College football playoff and March Madness drive significant seasonal volume. Bowl games and tournament matchups are available on Kalshi. Limited access so far on DraftKings or FanDuel, which is expected at this stage.

Soccer/Football

Polymarket leads soccer coverage due to its global user base, while Kalshi focuses on major tournaments. Domestic league matches are primarily available on Polymarket though you can find a handful on Kalshi. We expect all North American apps to offer World Cup contracts. 

Other sports

Kalshi offers the widest variety beyond major leagues, including golf majors, UFC/MMA, tennis Grand Slams, MLB, eSports and even darts. Coverage on other platforms is limited.

Other market categories: Politics – Crypto – Mentions – Elections

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