Three market types, three different games. Overround, commission, fees — and why your choice of platform type matters more than your choice of provider.
Most people choose a platform based on brand, marketing, or a friend's recommendation. This is backwards. The single most important decision is which type of market you trade on — because the type determines the structural cost you pay on every single trade, before you even try to find an edge.
Think of it as a ladder. Each step up removes a structural disadvantage:
A traditional bookmaker (Tipico, bet365, William Hill) sets the odds and takes the opposite side of your bet. They are your counterparty — and they have a massive structural advantage: the overround.
The overround is the percentage by which the implied probabilities of all outcomes exceed 100%. In a perfectly efficient market, the probabilities of all outcomes sum to exactly 100%. A bookmaker might offer odds that sum to 108%, meaning they take an 8% cut before anyone wins or loses anything.
At Tipico, overrounds regularly hit 110–115% on popular football markets. At bet365, it's typically 105–110%. This means that even a perfectly calibrated bettor with zero skill loses 5–15% of their turnover to the house over time. And when you do manage to win consistently? They limit or close your account.
An exchange (Betfair, Smarkets) removes the bookmaker entirely. Instead of trading against the house, you trade against other users. The exchange just matches buyers and sellers and takes a commission on net winnings — typically 2–5%.
This is fundamentally better because there's no built-in margin on the odds. The odds reflect actual supply and demand from other traders, not the bookmaker's artificially skewed prices. And the commission only applies to your profits, not your total stake.
The improvement is dramatic: roughly 40% of exchange users achieve profitability vs. about 3% at traditional sportsbooks. But exchanges still have limitations — they're mostly sports-only, liquidity can be thin on smaller markets, and Betfair's "premium charge" taxes their highest-volume winners.
Prediction markets (Kalshi, Polymarket) take the exchange model and extend it in three important ways:
First, the fee structure is even lower — typically around 1%, compared to 2–5% at exchanges. Second, they cover far more than sports: politics, economics, weather, culture, tech. This opens up genuine diversification — you can build a portfolio of uncorrelated positions across completely different domains. Third, they never discriminate against winners. Your account is never limited, restricted, or banned for being profitable.
To break even long-term, your edge must exceed the platform's structural cost. At Tipico (10%+ overround), you need 10%+ edge — almost impossible. At Pinnacle (2% overround), you need 2% edge — hard but achievable. At Kalshi (1% fee), you need just 1% edge. The platform choice determines the difficulty setting of the game.
| Dimension | Bookmaker | Exchange | Prediction Market |
|---|---|---|---|
| Your counterparty | The house | Other users | Other users |
| Cost structure | 4–15%+ overround | 2–5% commission | ~1% fee |
| Winner policy | Limits & bans | Mostly okay | No discrimination |
| Market categories | Sports only | Sports (+ some politics) | Multi-category |
| Can you sell early? | Cashout (poor terms) | Yes (full orderbook) | Yes (full orderbook) |
| Regulation | Gambling licenses | Gambling licenses | CFTC or crypto |
| Best for | Casual entertainment | Informed sports traders | Systematic traders |
If you're reading this series, the answer is almost certainly "prediction markets" as your primary venue, with Pinnacle as a reference pricing source and Betfair/Smarkets for specific sports markets where exchange liquidity is deeper.
See our Market Directory for detailed profiles of every platform.