Sports prediction markets

How sports markets differ from sportsbooks

A sportsbook is a bookmaker: it sets the odds, takes the other side of your bet, and bakes its profit into the price (the "vig" — that's why both sides of a spread bet pay -110). Polymarket is an exchange: you trade against other users through an order book, and nobody sets odds for you. The practical differences:

• No vig, but there is a spread. Instead of -110 on both sides, you pay the gap between the best buy and sell prices. On liquid championship markets the spread is small; on niche markets it can be brutal.
• No point spreads — just yes/no. Markets ask "Will the Chiefs win the Super Bowl?", not "Chiefs -3.5." You trade the outright outcome, which is simpler but offers fewer ways to express a nuanced view.
• You can sell mid-season. This is the real edge of the exchange model: buy a team at 12¢ in October, watch them go on a run, sell at 45¢ in January — no need to wait for the final whistle.

What you can trade

• Championship winners — Super Bowl, NBA Finals, World Series, Champions League, and more. The deepest sports liquidity lives here.
• Finals and playoff matchups — which teams reach the final, conference winners.
• Awards — MVP, Rookie of the Year, and similar voted awards (note: voters, not stats, decide these — a different kind of uncertainty).
• Season-long props — occasionally offered, e.g. win totals or record-related questions.

You generally won't find game-by-game lines like a sportsbook offers. Prediction markets cover the big, slow-moving questions, not tonight's point spread.

Pricing vs. the books

On major championships, prediction market prices and sportsbook futures usually sit close together — both are set by sharp crowds. The gaps appear at the edges: smaller leagues, awards voting, and longshots where the order book is thin. Some traders compare the two and buy where the price is better, but remember the all-in cost: a 2¢ better price means nothing if the spread and fees eat 4¢. See our fees guide for the full math.

In-season trading: the rhythm

Sports prices move on a predictable cycle: injuries, results, and narratives. A star quarterback's injury can crater a team's price in minutes; a surprise playoff run sends a longshot soaring. Two patterns to understand:

• Buy the dip after bad news, not the spike after good news. Markets overreact to single games — a contender losing in week 3 often gets priced like their season is over. If your preseason analysis was sound, the dip is the entry.
• Favorites bleed slowly, longshots die fast. A 70¢ favorite drifts down over a losing streak; a 5¢ longshot goes to zero on one bad weekend. Size accordingly.

The responsible framing

Sports is where discipline goes to die, because fandom feels like information. Watching every game does not give you an edge over a market that includes professional oddsmakers, models, and syndicates. The honest reasons to trade sports markets: you enjoy the engagement, the stakes are small enough to be entertainment spending, and you've accepted that losing is the most likely outcome of any individual trade.