Why most people lose money on Polymarket (the honest answer)

Look at any Polymarket user's lifetime P&L chart and one pattern repeats: slow accumulating losses punctuated by one or two wins. The pattern isn't bad forecasting — it's predictable process failures. Here's the causal chain.

1. Betting without measuring edge

Most users bet on events they feel strongly about. Feelings don't move prices — information does. If your estimate is 70% and the market is 65¢, you have +5pp edge. If your estimate is 70% and the market is 72¢, you have negativeedge and shouldn't bet, even if you feel certain.

2. Chasing longshots

“$5 to win $167” on a 3¢ longshot feels like free lottery. But you need 3%+ true probability, net of 2% slippage and 20¢ gas, which pushes breakeven to ~5%. Nearly no 3¢ market is 5% likely — that's what makes it 3¢.

3. Chasing losses

After 3 losses, users double up to “get back even.” Markets have no memory — the next bet's expected value doesn't know you're in a drawdown. Martingale on an unbounded loss tree bankrupts you. Always.

4. No bankroll rules

Betting any fixed $ amount regardless of bankroll or edge is uninformed sizing. Use fractional Kelly(¼ or ½ of full Kelly) so one bad run doesn't wipe you out. Rule of thumb: never more than 2% of bankroll on a single bet, regardless of edge.

5. Forgetting fees

At $10 bets with ~$0.40 combined slippage + gas, you pay 4% friction. Even a 10% gross edge becomes 6% net. Most users model 0% friction and quietly bleed.

The fix: a pre-bet checklist (edge ≥ 5pp, confidence ≥ 55%, price between 10¢ and 90¢, bet ≤ 2% of bankroll, liquidity ≥ $10k). PolyGuru's analysis page runs this check automatically.