The maximum number of contracts or dollar amount you can hold on a single market. Varies by platform.
Position limits cap the maximum exposure you can take on a single event contract. They exist for regulatory and risk management reasons.
PredictIt historically had the tightest limits ($850, now expanded to $3,500). Kalshi's limits vary by market. Polymarket and Robinhood generally have no hard limits but may restrict size on individual markets.
Position limits affect strategy: tight limits make it harder to size bets with Kelly, and they make large-scale arbitrage difficult. Multi-platform strategies help work around single-platform limits.
An exchange where participants trade contracts based on the outcome of future events, with prices reflecting collective probability estimates.
Kelly CriterionA formula for optimal bet sizing that maximizes long-term bankroll growth based on your edge and the odds.
BankrollThe total amount of money set aside exclusively for betting or trading. Never money you can't afford to lose.