How Prediction Market Odds Work

Last updated: July 22, 2026

The TL;DR:

There's no bookmaker setting odds on Predict: the market sets the price, and that price is the crowd's live estimate of probability.

A share's price in cents is its implied probability. A share trading at 65¢ suggests a 65% chance of that outcome.

The bid-ask spread shows how settled the market is currently. Tight spreads mean traders broadly agree, while wide ones indicate uncertainty.

Prices move as new information becomes clear and traders act on it, so the odds update continuously instead of being fixed at kickoff.

"Odds" Isn't Really the Right Word

"The odds" in a prediction market differ from those seen at a sportsbook.

A bookmaker sets odds to guarantee itself a cut, regardless of outcome. But a prediction market has no bookmaker: prices come from traders putting their money behind their positions, and they're matched against whoever wants to take the opposite side.

That's why, on Predict, you'll see prices and probabilities rather than odds. The mechanics are closer to a stock exchange than a sportsbook.

How Share Prices Work as Implied Probabilities

Every share on Predict resolves to either $1 or $0: $1 if it matches the outcome, $0 if it doesn't.

Because of that binary payout, a share's price sits somewhere between 0¢ and $1, and that price is the market's live estimate of how likely the outcome is. A YES share trading at 65¢ implies the market currently sees roughly a 65% chance of YES happening.

Suppose Candidate McCandidateFace's YES shares in an election market trade at 72¢. That price says the market currently prices McCandidateFace's odds of winning at about 72%. If you buy at 72¢ and McCandidateFace wins, your share pays out $1, a 28¢ profit. If they lose, the share is worth $0.

Prices adjust as traders buy and sell, so that implied probability is a live number, not a one-time forecast set when the market opens.

Reading the Order Book

Prices come from the order book: every open buy order (a bid) and sell order (an ask) waiting to be matched.

The best bid is the highest price a buyer is currently offering. The best ask is the lowest price a seller will accept. The gap between them is the spread.

A tight spread (e.g., a cent between bid and ask) means that traders broadly agree on the probability. A wide spread means the market hasn't settled: either there's a serious difference of opinion, or not enough people trading yet for the price to converge.

You can trade at the current best price with a market order, or set your own price and wait for a match with a limit order.

Why Prices Move

Prices shift for the same reason odds do at a sportsbook: new information changes what people think will happen. A leaked poll, an injury report, a rate decision. Traders react by buying or selling, and the price moves to reflect it.

Unlike posted odds, there's no fixed schedule for this. A prediction market updates the moment someone is willing to trade at a new price, not just when a bookmaker chooses to move the line.

As a market approaches resolution, prices tend to converge toward $0 or $1 as uncertainty resolves, unless the outcome stays genuinely close until the end.

Multi-Outcome Markets: Prices That Sum to $1

Not every market is a straight YES/NO. Multi-outcome markets let more than two results trade against each other: who wins a tournament, which candidate wins a primary, and so on.

The mechanics are the same. Each outcome's price is its implied probability, and across all outcomes in a market, prices sum to roughly $1 (100%). If five candidates are trading at 45¢, 20¢, 15¢, 12¢ and 8¢, that's the market pricing a 45% chance for the front-runner, and so on down the field.

Converting a Price to a Probability

The math is simple: divide the price in cents by 100. A share at 35¢ implies a 35% probability. A share at 8¢ implies 8%.

There's no vig to back out first, unlike converting sportsbook odds to a "fair" probability. The price you see is already the market's probability estimate.

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Frequently Asked Questions

Why does Predict call it "price" instead of "odds"?

Because there's no bookmaker setting odds with a built-in edge. On Predict, prices come directly from traders buying and selling shares, and those prices already are the market's probability estimate.

How do I convert a price to a percentage?

Divide the price in cents by 100. A share trading at 60¢ implies a 60% probability.

What does a wide bid-ask spread mean?

That traders disagree on the probability, or that there isn't enough trading activity yet for the price to settle. A tight spread means the market has largely converged on one number.

Are prediction market prices always accurate?

Not always, but historically well. Because traders put real money behind their view, prices tend to reflect the best available public information more efficiently than polls or pundits, though a thinly-traded market can still be wrong or slow to update.

Why do multi-outcome prices sum to about $1?

Because exactly one outcome will pay out $1 and the rest $0. If outcome prices summed to much more or less than $1, traders could profit by buying or selling the full set, and that opportunity gets traded away quickly.

Odds & Pricing Glossary

Implied probability

The probability a share's price represents: price in cents divided by 100.

Bid

An open order to buy a share at a specified price.

Ask

An open order to sell a share at a specified price.

Spread

The gap between the best bid and best ask. Narrow spreads signal agreement on price; wide ones signal uncertainty or thin trading.

Order book

The live list of all open bids and asks for a market, ranked by price.

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