How Prediction Markets Resolve: Settlement Rules

A prediction market does not settle on what “obviously happened.” It settles under a written contract. That contract defines the question, deadline, evidence source, edge cases, and process that turn winning shares into $1 and losing shares into $0.

The headline attracts attention. The resolution rule controls the money. Reading it before trading is the prediction-market equivalent of checking what you are signing.

Resolution and settlement are related but different

Resolution is the formal determination of the winning outcome. Settlement is the financial step that credits winning contracts and makes losing contracts worthless.

For the payout arithmetic behind that final $1 or $0 value, see what a 60-cent prediction-market contract means.

An event can appear finished before the market resolves. A television network may call an election, a referee may signal a final score, or a company may announce a number. The contract may require a different source, a certification, a correction window, or a specific deadline.

The five parts of a good resolution rule

1. Exact outcome. What fact makes Yes win?
2. Time window. Must it happen before a particular date, time, or time zone?
3. Resolution source. Which league, agency, publication, database, or official record controls?
4. Edge cases. What happens after a postponement, recount, cancellation, tie, merger, correction, or ambiguous announcement?
5. Fallback process. What happens if the named source is unavailable or inconclusive?

If one of these is missing, the trade includes rule risk in addition to event risk.

Why two similar markets can settle differently

Consider two contracts that sound like “Will Candidate A win?” One may settle when a major news organization calls the race. Another may wait for state certification. A third may ask who is inaugurated by a date.

Those are different contracts. A recount, court case, withdrawal, or replacement can separate their outcomes. Prices can differ because traders are evaluating both the event and the wording.

Sports markets have the same issue. “Team wins the game” needs rules for postponements, suspended games, forfeits, venue changes, and official statistical corrections. Season markets need to define whether playoffs count and what happens when schedules change.

How Polymarket says resolution works

Polymarket’s official documentation says its markets are resolved using the UMA Optimistic Oracle. Once the result is clear, an outcome can be proposed with a bond. The proposal then enters a challenge period; the current help article describes a two-hour window. An undisputed, validated proposal can finalize. A disputed proposal follows UMA’s dispute process.

The process does not replace the individual market rule. The oracle applies that rule. Polymarket tells users to find the predefined resolution rules under the market’s order book, and states that winning shares receive $1 while losing shares become worthless after resolution.

How centralized exchanges differ

A centralized exchange such as Kalshi publishes market-specific rules and determines outcomes under its exchange framework rather than Polymarket’s on-chain oracle process. The practical lesson is the same: do not transfer assumptions from one venue to another.

Read the rule attached to the exact ticker or contract. A screenshot of a headline without the rule can omit the most important condition.

Common settlement traps

• Projected versus certified. A projection can be persuasive without being the named resolution event.
• Before versus by. Contract language and time zones can determine whether a boundary event counts.
• Announced versus effective. A policy can be announced on one date and take legal effect later.
• Game result versus series result. One contest and a best-of series are separate markets.
• Initial release versus revised data. Economic statistics are often corrected; the rule should identify which release controls.
• Source silence. If the named source never publishes a clear answer, a fallback clause becomes important.

What invalid, ambiguous, or canceled can mean

Do not assume an invalid market always pays 50 cents or automatically refunds the original amount. Platforms and products can handle invalidity differently, and multi-outcome markets can create additional rules.

Look for terms such as “invalid,” “canceled,” “void,” “insufficient information,” and “all other outcomes.” If the market does not state the treatment clearly, the uncertainty should be part of your decision not to trade it.

Settlement timing affects capital

A correct position can remain unsettled while the required source catches up. During that period, capital may remain tied to the contract and trading can be limited or closed.

This matters when comparing two otherwise similar markets. A contract that settles on an official publication several weeks later is not economically identical to one that resolves shortly after the event. Time has a cost even when both eventually pay $1.

A pre-trade resolution checklist

1. Copy the exact market question into your notes.
2. Identify the date, time, and time zone.
3. Open the named resolution source and confirm that it exists.
4. Search the rule for postponement, cancellation, correction, tie, and dispute language.
5. Ask what evidence would make your expected real-world outcome fail to satisfy the written contract.

If you cannot explain the settlement rule in one sentence, you do not yet understand the position.

Frequently asked questions

When do winning prediction-market contracts pay? After the result required by the contract has been determined and finalized under the venue’s process. The event ending and the contract settling are not always simultaneous.

Can a market settle differently from the news? Yes, if the news reports a different fact or uses a different threshold than the contract. The named source and wording control.

Can I trade during a dispute? Availability depends on the market and platform state. Never assume you can exit after the event.

What is resolution risk? It is the risk that ambiguous wording, evidence, timing, or a dispute causes a result or delay different from what you expected.

Sources and methodology

Polymarket mechanics were checked against its official How Are Prediction Markets Resolved? documentation. For every live trade, the market-specific rule and the venue’s current terms supersede this general explainer.