Outcome Trading: The Unified Framework for Sportsbooks and Prediction Markets
Outcome trading unifies sportsbooks and prediction markets under 1 framework. 5 shared formulas, platform-specific edges, and the math that bridges both.
What Is Outcome Trading?
Outcome trading is any transaction where you risk capital on the result of a discrete, verifiable event. An NFL moneyline bet at -150 is outcome trading. A Kalshi contract on whether the Fed cuts rates in June is outcome trading. A Polymarket position on the next Supreme Court retirement is outcome trading. The platforms differ. The regulation differs. The math is identical.
The term matters because the industries are converging. Sportsbooks are adding event contracts. Prediction markets are listing sports. DraftKings runs a CFTC-regulated prediction market. Robinhood routes orders through Kalshi. FanDuel partners with CME Group. The line between "sports betting" and "prediction market trading" is dissolving, and the traders who see both sides of the table have a structural edge over those who see only one.
Market Math exists to serve outcome traders. Not just sports bettors. Not just prediction market traders. Anyone who risks capital on binary, verifiable events and wants the math to be right. Every tool on this site works across both platform types because the underlying formulas do not change when you switch from American odds to contract prices.
Why Sportsbooks and Prediction Markets Are the Same Thing
Strip away the branding and regulation, and sportsbooks and prediction markets are both probability exchanges. You take a position at a price that implies a probability. If your estimate of the true probability is more accurate than the price, you profit. If it is less accurate, you lose. That is the complete framework.
The surface-level differences obscure this shared structure:
| Feature | Sportsbook | Prediction Market |
|---|---|---|
| Price format | American odds (-110) | Contract price ($0.52) |
| Counterparty | The house | Other traders |
| Cost structure | Hidden vig in the odds | Explicit fees on profits |
| Market types | Sports-heavy | Politics, economics, weather, sports |
| Exit | Usually locked until settlement | Trade out anytime on the order book |
These differences are real. They create different edges, different risks, and different optimal strategies. But the core math underneath is the same. Expected value determines whether a position is worth taking. Kelly sizing determines how much to risk. The vig or fee structure determines your breakeven threshold. Convert any position between formats with the prediction market converter and the equivalence becomes obvious.
Worked example. An NBA game is priced at -150 on a sportsbook (implied probability 60%) and Yes $0.57 on Kalshi (implied probability 57%). Are these the same bet? Yes. The sportsbook embeds vig. After de-vigging the line, the true implied probability is approximately 58%. Kalshi's price is 57%. The 1% gap is your starting point for finding edge. The arbitrage calculator tells you whether that gap survives fees on both sides.
The Convergence: Two Industries Becoming One
The sportsbook-to-prediction-market pipeline is accelerating. Here is what happened in the past 18 months:
Sportsbooks moving toward prediction markets. DraftKings launched DraftKings Predictions, a CFTC-regulated event contract platform. FanDuel partnered with CME Group to offer event contracts in all 50 states. These are not sportsbook bets. They are binary contracts that settle at $0 or $1, traded on regulated exchanges. The mechanics are prediction markets. The distribution channel is a sportsbook app.
Prediction markets moving toward sportsbooks. Polymarket already lists sports contracts globally. Kalshi added sports event contracts in 2025. The contract pricing is identical to a moneyline bet repackaged as a $0-$1 binary. A contract at $0.40 is the same as +150. The market converter proves it.
Brokerages entering the space. Robinhood and Coinbase now offer event contracts through Kalshi. Webull offers them at zero commission. These are retail investing platforms, not gambling companies, offering the same instruments that sportsbooks and prediction markets sell.
The convergence is not coincidental. Binary outcomes are the simplest possible financial instrument. Every platform that deals in risk eventually arrives at the same product. The wrapper changes. The regulations change. The math stays the same.
For outcome traders, this convergence creates opportunity. More platforms listing the same events means more price disagreements. More price disagreements means more cross-platform edge. The traders who move fluidly between sportsbooks, prediction markets, and brokerage event contracts will capture that edge. The ones locked into a single platform type will not.
The 5 Shared Formulas Every Outcome Trader Needs
Whether you are placing a moneyline bet or buying a prediction market contract, five formulas govern every decision. The inputs change. The math does not.
1. Expected Value (EV)
EV = (Win Probability x Profit) - (Loss Probability x Stake)
This is the only number that tells you whether a position is worth taking. Positive EV means the trade profits over time. Negative EV means it loses. Run every position through the EV calculator before risking capital.
Sportsbook example. A +200 underdog with 40% true probability. EV = (0.40 x $200) - (0.60 x $100) = +$20 per $100 risked. That is a strong +EV bet.
Prediction market example. A contract at $0.35 with 42% true probability. EV = (0.42 x $0.65) - (0.58 x $0.35) = $0.273 - $0.203 = +$0.07 per contract. Before fees. After Kalshi's fee structure, the net EV drops but remains positive.
Same formula. Different price format. Same decision framework. For the full breakdown of EV across both contexts, read the expected value guide and the prediction market strategy guide.
2. Vig and Fee Extraction
Every platform takes a cut. The mechanism differs, but the effect is identical: your breakeven probability is higher than the implied probability.
Sportsbooks embed their margin in the odds. A -110/-110 line implies 104.8% total probability. The extra 4.8% is the vig. Prediction markets charge explicit fees on profits. Kalshi takes approximately 7% of net gains. Polymarket earns through the bid-ask spread.
At most price points, prediction market fees cost 40-60% less than sportsbook vig. That structural cost advantage is one reason outcome traders benefit from accessing both platform types. Use the fee calculator to compare effective costs on any specific trade.
3. Kelly Criterion
Kelly % = (bp - q) / b
Where b = decimal odds minus 1, p = win probability, q = loss probability.
Kelly tells you how much of your bankroll to risk on any +EV position. It applies identically to sportsbook bets and prediction market contracts. The formula does not care about the platform. It cares about your edge and the odds.
In practice, use half Kelly or quarter Kelly. Full Kelly is mathematically optimal but produces stomach-churning drawdowns. This is true on sportsbooks, on Kalshi, on Polymarket. The math of bankroll management does not change when you switch platforms.
4. Implied Probability Conversion
Sportsbook odds and prediction market prices are different representations of the same thing: implied probability.
| Format | Example | Implied Probability |
|---|---|---|
| American (favorite) | -150 | 60.0% |
| American (underdog) | +200 | 33.3% |
| Contract price | $0.60 | 60.0% |
| Decimal odds | 2.50 | 40.0% |
Every outcome trading decision starts with converting the price to implied probability, then comparing it to your estimate of true probability. If your estimate is higher than the implied probability (after adjusting for fees), you have edge. The prediction market converter does this translation between all formats instantly.
5. Cross-Platform Arbitrage
When two platforms disagree on the same event by more than the combined fees, a risk-free profit exists. This is unique to outcome trading across platform types. A pure sportsbook bettor cannot access prediction market prices. A pure prediction market trader misses sportsbook lines. The outcome trader who watches both captures arbs that neither side sees alone.
Worked example. A political event trades at $0.42 on Kalshi (implies 42%) and the No side is available at +140 on a sportsbook (implies 41.7%). Combined implied probability: 83.7%. A 16.3% raw arb. After Kalshi's 7% winner fee, it narrows but remains profitable. The arbitrage calculator gives you the exact allocation split and guaranteed profit. For the full execution framework, read the cross-platform arbitrage guide.
Where Each Platform Type Has an Edge
Outcome trading is not about choosing sportsbooks over prediction markets or vice versa. It is about knowing where each platform type offers a structural advantage and routing accordingly.
Sportsbooks are sharper on mainstream sports. Decades of pricing data, sophisticated models, and massive liquidity make NFL, NBA, and MLB lines extremely efficient. The closing line at Pinnacle is widely considered the best estimate of true probability for major sports. Use it as your benchmark. Read the closing line value guide for why CLV matters.
Prediction markets are sharper on non-sports events. Election outcomes, economic indicators, Fed decisions, and geopolitical events attract subject matter experts who trade their information directly. The price discovery is often more accurate than polls, models, or expert panels. The prediction market vs polls comparison shows the accuracy gap.
Sportsbooks have thinner margins on reduced-juice lines. Books like Pinnacle offer -104 or -105 on liquid markets. That is a 2.4% hold. Cheaper than most prediction market fee structures at certain price points.
Prediction markets allow early exits. On a sportsbook, most bets lock until settlement. On a prediction market, you can sell your position at any time on the order book. This changes the risk calculus fundamentally. A hedging strategy that is impossible on a sportsbook becomes trivial on a prediction market.
Prediction markets cover events sportsbooks cannot. Will inflation exceed 4%? Will the government shut down? Who will be the next Fed chair? These contracts exist only on prediction markets. For the full breakdown of these structural differences, read the sportsbook vs prediction market comparison.
Common Mistakes Outcome Traders Make
Treating sportsbook odds and prediction market prices as directly comparable without adjusting for vig. A sportsbook line of -150 does not mean 60% probability. It means 60% probability with vig included. Strip the vig first, then compare to the prediction market price. The de-vig calculator does this automatically.
Ignoring fees when calculating EV. A contract that looks +EV before fees can be -EV after fees. This is especially dangerous on Kalshi for near-50% contracts where the fee takes the largest absolute bite, and on Polymarket when the spread is wide. Always calculate fee-adjusted EV.
Oversizing positions because "the math checks out." Finding +EV is necessary but not sufficient. Without proper position sizing, a string of correct +EV trades can still bankrupt you through variance. Half Kelly is the starting point for practical sizing.
Not accounting for correlation. Three individually +EV positions that all depend on the same underlying factor (voter turnout, economic sentiment, team health) create concentrated risk. Your effective exposure is higher than the sum of individual positions suggests. The correlation calculator quantifies the actual portfolio risk. Read the correlated positions guide for the full framework.
Why the Term "Outcome Trading" Matters
Language shapes how you think about markets. If you think of yourself as a "sports bettor," you look at sportsbooks. If you think of yourself as a "prediction market trader," you look at contract platforms. Both are half the picture.
Outcome trading as a framework forces you to see the complete landscape. The same event priced on different platforms. The same math applied through different interfaces. The same edge captured wherever the pricing is least efficient.
This is not a marketing term. It is a practical orientation. When DraftKings launches a prediction market and Robinhood routes event contracts through Kalshi and Polymarket lists NBA games, the traditional categories stop being useful. What remains useful is the math: EV, vig, Kelly, correlation, and the discipline to apply them consistently.
Market Math builds every tool to work across platform types. The EV calculator handles sportsbook odds and prediction market prices. The arbitrage calculator finds gaps between sportsbooks and prediction markets. The prediction market converter translates between formats. Because the math does not care what you call it.
The traders who will profit most over the next decade are the ones who see outcome trading as a single discipline, not two separate hobbies. The platforms are converging. The math was always the same.
Frequently asked questions
- What is outcome trading?
- Outcome trading is risking capital on the result of a discrete, verifiable event. It includes sportsbook bets, prediction market contracts, and event contracts on brokerage platforms. The term unifies these under one framework because the underlying math is identical.
- What is the difference between a sportsbook and a prediction market?
- Sportsbooks set odds and act as your counterparty (you bet against the house). Prediction markets use order books where you trade against other participants. Sportsbooks embed costs in the odds (vig). Prediction markets charge explicit fees. Both price the same underlying probabilities.
- Can you trade the same event on a sportsbook and a prediction market?
- Yes, and this creates arbitrage opportunities. Sports events are increasingly listed on prediction markets, and political events occasionally appear on sportsbooks. When both platforms price the same event differently, outcome traders can exploit the gap.
- What math do you need for outcome trading?
- Five formulas cover the core: expected value (whether a position is worth taking), vig/fee calculation (your true cost), Kelly criterion (how much to risk), implied probability conversion (translating between price formats), and cross-platform arbitrage (capturing pricing disagreements).
- Is outcome trading the same as gambling?
- The label depends on process, not platform. Traders who calculate expected value, size positions with Kelly, and verify edge systematically are trading. Those who skip the math are gambling. This distinction applies equally to sportsbooks, prediction markets, and stock options.