Why most prediction market traders lose

People assume losing traders are bad at forecasting. Mostly they are not — they are roughly as good at picking winners as anyone else, and they still lose. The damage happens around the forecast, not in it.

1. Betting the story instead of the number

A compelling narrative is not an edge, because the market has heard it too. If you cannot state your probability *and* the price *and* the gap between them, you do not have a position — you have an opinion with money attached. The fix is mechanical: write your number down before you look at the price.

2. Ignoring the cost of being there

A 2-point disagreement with a −110 line is not a small edge, it is a loss: the vig is over four points. Every gap has to clear the round-trip cost before it counts as anything. Most "edges" people act on do not.

3. Sizing by conviction

Feeling strongly about a market is not information about its variance. Betting big on the ones that feel good and small on the ones that do not is how a real edge gets converted into a random walk — because the ones that feel good are disproportionately the ones where you have talked yourself into something.

4. Trading markets you do not understand

Every market has people in it who know more than you about that specific thing. On an obscure market, the person taking the other side is often one of the three people on earth who follows it closely. Breadth is not an advantage here; it is adverse selection. Pick a lane where public information is genuinely enough.

5. No record, so no learning

Without a log of what you predicted, at what price, and what happened, memory does the accounting — and memory is generous. Ask someone with no records what their hit rate is and they will overstate it, every time, without lying. You cannot fix a process you cannot see.

6. Confusing activity with edge

There is no requirement to have a position. Most markets, most days, are priced about right, and the correct action is nothing. Traders who need action find reasons, and reasons found under pressure are worse than reasons found in the ordinary course of looking.

What the fixed version looks like

1. 1Estimate before you price. Write it down.
2. 2Subtract the full round-trip cost. What is left is the edge.
3. 3Size on a fixed fraction of that edge, not on feel.
4. 4Cap correlated exposure — five markets on one election are one bet.
5. 5Log every call and grade it when it settles.
6. 6Skip freely. No edge is a complete answer.

You do not need to beat the market on many questions. You need to know which few you are beating it on, and to bet those in a size that survives being wrong about some of them.