Why do most prediction market traders lose money?

There is a number that puts this whole category in perspective: across prediction markets, a large majority of participant accounts are net negative. It is not a secret, and it is not because the participants are stupid. It is because the structure is tilted in a way most people never see.

The illusion of a high win rate

The most dangerous metric in this space is win rate. Here is why.

Buy “Yes” contracts on ten different “90% favourites” at $0.90 each. Nine of them win — a 90% win rate that feels great. But look at the money:

• Nine wins pay $0.10 profit each = +$0.90
• One loss costs $0.90 = −$0.90

You broke even — at a 90% win rate. And that is before fees and the spread, which push you into negative territory.

The point is not that favourites are bad. The point is that win rate and profitability are unrelated in a market with asymmetric payoffs. People who brag about win rate are, almost always, losing money and not realising it.

Where the money actually goes

Three costs stack up on every round trip:

1. The spread — you buy at the ask and sell at the bid. On a $0.60 contract with a 2-cent spread, that is about 3.3% gone immediately.
2. The taker fee — highest near 50% probability, exactly where most casual traders trade.
3. Adverse selection — when you trade, the person on the other side often knows something you do not. You are systematically taking the worse side of informed flow.

Add those together and a casual trader needs a genuine probability edge of 5% or more just to break even. Most people do not have that edge — and do not know they need it.

Who does make money

The consistent winners fall into a few specific groups, none of which is “smart casual trader”:

• Market makers, who earn the spread and rebates instead of predicting outcomes.
• Speed arbitrageurs, who correct cross-venue price gaps in under a second.
• Specialists, who hold a real information advantage in a narrow niche (a court system, a specific league, a policy area).

Notice what is missing: people who are “good at predicting the news”. That is not a profession here, because everyone has the news.

The honest framing

The question to ask is not “can prediction markets make money?” — they can, for the groups above. The question is “which group am I in?” If the answer is “none of them”, the expected outcome is the same as it is for most participants: a slow bleed disguised as a series of near-misses.