Common Polymarket mistakes: a reference list for new traders
The 10 most common mistakes new Polymarket users make, in order of how much money each costs. Bookmark and consult before any bet.
Every expensive Polymarket mistake has a named cause. Here's a reference list — print it, pin it to your monitor, check before clicking buy.
The 10 most expensive mistakes
- Betting on extreme prices (<5¢ or >95¢) — risk/reward is brutal, liquidity is thin, slippage eats the margin.
- Not reading resolution criteria— many markets have ambiguous trigger conditions. “By end of year” can mean UTC midnight or the event organiser's local time.
- Ignoring liquidity — under-$10k markets move on your bet. A $50 bet can walk the book 2-3¢ and reduce your effective edge to zero.
- Over-sizing — no Kelly discipline means one bad run wipes the bankroll. Max 2% per bet, scaled by edge.
- Chasing losses — doubling up after losses bankrupts mathematically, not theoretically. Markets have no memory.
- Confusing accuracy with edge — 80% accurate on 80¢ priced favorites = basically zero profit.
- Betting sentiment, not probability— “I think X will happen” is not a probability. Write down a specific % before betting.
- Ignoring fees on small bets — $5 bets with $0.40 friction = 8% cost before EV. Minimum viable bet: $20-30.
- Holding through resolution delays — some markets resolve slowly or stall. Capital tied up = opportunity cost.
- Ignoring oracle risk — UMA oracle can misresolve. Highly contentious markets have disputed resolutions that take weeks.
Pre-bet checklist
- Price between 10¢ and 90¢?
- Liquidity ≥ $10k?
- Resolution criteria clear?
- Your probability written down (not just “feels likely”)?
- Edge ≥ 5pp after costs?
- Bet ≤ 2% of bankroll?
Six yeses = proceed. Five or fewer = skip. PolyGuru's analysis page runs all six checks automatically and shows the result with cited reasoning.
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