Step-by-step explainers for reading odds, choosing a platform and managing risk.
Polymarket does not decide its own outcomes: UMA’s Optimistic Oracle does. Proposals and $750 bonds, the two-hour challenge window, disputes, the UMA token-holder vote, who keeps which bond, and the controversies.
PredictIt is the original US political prediction market. How its contracts, 10% profit fee and 5% withdrawal fee work, what changed with its $3,500 limit, and when Kalshi or Polymarket is the better choice.
The Brier score is the average squared gap between a forecast and what happened. The formula, worked examples, what counts as a good score, the skill score, and how to score Polymarket and Kalshi prices.
Expected value tells you whether a trade pays on average. The EV formula for prediction market contracts, worked examples with fees, break-even probability, annualised returns, and the mistakes that turn +EV into losses.
Kelly sizing tells you what share of your bankroll to put on a trade with an edge. The formula for a $1 contract, worked examples, why most traders use half Kelly, and the mistakes that make Kelly dangerous.
Hedging locks in profit or limits a loss by betting on the other side. How to hedge a Kalshi or Polymarket position, how to hedge a sportsbook futures ticket with one simple rule, partial hedges, and what hedging costs.
A market order fills now at whatever the book offers; a limit order waits for your price. How each works on Kalshi and Polymarket, what they cost in fees and slippage, Polymarket’s GTC, GTD, FOK and FAK types, and how to cash out early.
Every market settles on its written rules, not on what traders think happened. Who decides outcomes on Kalshi and Polymarket, how UMA disputes work, what happens with injured or scratched players, postponed games and revised data.
Bots quote prices, chase arbitrage and copy whales on Polymarket and Kalshi. How a trading bot is built on each API, what fees did to bot strategies in 2026, how copy trading really works, and the malware wave aimed at Polymarket bot users.
