What Does 63% Mean?
In a prediction market, if a YES contract trades at $0.63, traders often read it as the market implying about a 63% chance.
But that is implied probability, not true probability.
No one knows the true probability. The price is the result of current buy and sell orders.
Where Does the Price Come From?
Event contract prices come from the order book.
Someone bids 0.62 for YES, someone offers 0.64, and trades may print around 0.63.
That price includes:
- Participants’ views
- Market liquidity
- Bid-ask spread
- Trading fees
- Market maker inventory risk
- News and sentiment shocks
Do not treat price as a truth dashboard.
Implied Probability vs. Fair Price
Suppose you believe an event has a 70% chance.
If YES trades at 0.50, you may see value.
If YES trades at 0.68, you may still be directionally right, but after fees, spread, slippage, and uncertainty, your edge may be very thin.
Your view: 70%
Market price: 68%
Apparent edge: 2%
After costs: maybe no edge
Many prediction market losses come from being roughly right but paying too much.
When Can Prices Be Distorted?
- The market just opened and has little volume
- News just hit
- Resolution is near but rules are disputed
- A large trader temporarily moves price
- Liquidity is thin
Ask Before Trading
- What is my own probability estimate?
- Is the gap versus market price large enough?
- How much edge do spread and fees remove?
- If price does not move, am I willing to hold until resolution?
- Do the rules support my interpretation?
Quiz
Q1. A $0.63 YES contract usually means:
A. Market-implied probability around 63% B. The platform guarantees the event
Q2. Is implied probability the same as true probability?
A. Yes B. No
Q3. Why can you be directionally right and still lose?
A. You paid too much and costs removed the edge B. Probability is always useless
Answer Key
Q1: A Q2: B Q3: A
Further reading: CFTC — Event Contracts · Investopedia — Order Book · Wikipedia — Prediction Market
For education only. Event contracts can settle at zero. Read the rules first.
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