Twelve checks for a prediction market trade: eight before you buy (rules, end date, where you may trade, break-even after fees, spread and depth, your own probability, position size, overlapping bets) and four after (clarifications, payout timing, an exit plan, a record). Print it or tick the boxes on screen.
Before you buy
The rules name the event, the resolution source and edge cases; the title is a summary. How
Trading stops at the end date; deadlines are often 11:59 PM US Eastern Time. How
polymarket.com and Polymarket US have different access rules by country and state. How
A taker pays shares x rate x p x (1 - p); the break-even chance is the price plus that fee per share. How
A wide spread or a thin book means your average fill is worse than the price shown. How
Without a number of your own there is no way to know whether the price is too high. How
Stake a share of your bankroll you can lose; full Kelly swings hard, half or quarter Kelly less so. How
Several bets on the same election or team can all lose together. How
After you buy
A clarification can change what counts; it clears the order book. How
Undisputed markets settle within hours of the end; disputes add days. How
A price target or a news event that changes your view, set before emotions do it for you. How
Price, size, fees and your probability at entry: the only way to learn whether your forecasts are any good. How
Frequently asked questions
What should I check before buying on Polymarket?
The rules and resolution source, the end date and time zone, whether you may trade from your location, the break-even chance after fees, the spread and depth, your own probability, the position size and how it overlaps your other bets.
Is this financial advice?
No. It is a list of things to look at; the decision and the risk are yours.
Free to share and print under CC BY 4.0 with a link to this page. Companion sheet: Polymarket odds cheat sheet. Polymarket View is independent and not affiliated with Polymarket; not financial advice.