What are YES and NO shares in a prediction market?

Short answer

YES and NO shares are the two tradeable tokens in a binary prediction market. YES shares pay out if the event occurs, NO shares pay out if it does not, and together they always settle to a fixed total — typically one dollar.

What to know

A binary prediction market works by splitting a single question into two complementary positions. If you believe an event will happen, you can buy YES shares. If you believe it will not happen, you can buy NO shares. When the market resolves, one side receives the full payout and the other receives nothing.

The price of each share reflects the crowd's collective judgment about probability. A YES share trading at forty cents implies the market collectively estimates a forty percent chance the event occurs. A NO share on the same market would trade near sixty cents, since the two prices sum to approximately one dollar. This relationship holds throughout the life of the market because arbitrage keeps the pair in balance.

Shares can be bought and sold before the market resolves. If new information arrives that makes an outcome more likely, YES shares tend to rise in price and NO shares tend to fall, and vice versa. This means participants can exit positions early without waiting for the final outcome, locking in a gain or cutting a loss depending on how the market has moved.

When the outcome is officially confirmed by the market's resolution source, winning shares redeem for the full payout — usually one dollar each — while losing shares expire worthless. The resolution source is determined in advance and is typically a reputable public record, such as an official result, a regulatory announcement, or a news organization.

Key points

• YES shares pay the fixed settlement amount if the stated event happens; NO shares pay if it does not happen.
• The prices of YES and NO shares on the same outcome add up to roughly one dollar, reflecting complementary probabilities.
• Share prices move continuously as participants trade, so the market price at any moment represents an implied probability.
• You can sell your shares before resolution; you do not have to hold until the outcome is decided.
• Both sides of a market can only resolve in one direction — one share type ends at full value, the other at zero.
• The resolution criteria are fixed when the market opens, so participants know in advance exactly what determines the outcome.

How it compares

• Opinion polls ask people what they think will happen but carry no financial stake; prediction market prices are backed by real money, which creates an incentive to form careful judgments.
• Traditional sports betting offers fixed odds set by a bookmaker; prediction markets set prices dynamically through continuous trading, so the price can shift as conditions change.
• Stock shares represent ownership in a company with no fixed expiry; YES and NO shares are binary contracts that settle to a known value on a specific date.
• A coin-flip bet is purely random; prediction market share prices incorporate available information, so they can reflect genuine differences in probability across participants.

FAQ

What happens if I hold YES shares and the event does not happen?

Your YES shares expire worthless and you receive nothing for them. The full settlement value goes to holders of NO shares instead.

Can I sell my shares before the market resolves?

Yes. Shares trade continuously, so you can sell at the current market price at any time before resolution. The amount you receive depends on what other participants are willing to pay at that moment.

Why do YES and NO prices add up to roughly one dollar instead of exactly one dollar?

In practice, small trading fees or bid-ask spreads can cause the sum to differ slightly from one dollar. In a frictionless market the two prices would sum to exactly one dollar because they represent mutually exclusive and exhaustive outcomes.

What determines who resolves the market?

The resolution source is specified in the market's terms before trading begins. It is typically a named public authority, official record, or established news source. Participants can review the resolution criteria before taking any position.

Is a fifty-cent share price a signal to buy?

Not necessarily. A price near fifty cents simply means the market is close to evenly split on the outcome. It does not mean the share is undervalued or overvalued — only that participants collectively see roughly equal odds.

What if the outcome is ambiguous or the event is cancelled?

Many markets include explicit rules for edge cases such as postponements, cancellations, or disputed outcomes. Common resolutions include returning the original price to all participants or resolving based on the closest applicable outcome. The specific handling depends on the rules stated when the market was created.