How Kalshi and Polymarket markets resolve: settlement rules, disputes, and what happens if a player doesn’t play
Every market settles on its written rules, not on what traders think happened. Who decides outcomes on Kalshi and Polymarket, how UMA disputes work, what happens with injured or scratched players, postponed games and revised data.
A prediction market contract pays $1 if its question resolves "Yes". Who decides, using what source, by what deadline is written in the market's rules, and those rules, not common sense, decide whether you get paid. Most markets settle without any drama. The ones that do not cost traders a lot of money, so it pays to know how resolution works on each platform.
Read the rules tab first
Every market on Kalshi and Polymarket has a rules or "resolution" section. Look for:
- The source: the official league result, the Bureau of Labor Statistics release, the Associated Press call, a named website.
- The deadline: what happens if the event has not happened by a set date.
- Edge cases: ties, postponements, recounts, revisions, players who do not play.
If the rules do not cover a situation you can imagine, assume it will be settled in a way you did not expect, and size your position accordingly.
How Kalshi settles markets
Kalshi is a CFTC-regulated exchange and settles every market itself, using the source named in the contract terms. When the source publishes (a final score, an inflation number, an official certification), Kalshi settles the market and the $1 per winning contract lands in your balance. There is no community vote.
Sports: what if a player does not play?
This is where Kalshi differs most from sportsbooks. A sportsbook usually voids a player bet and refunds you if the player does not play. On Kalshi, there is no refund in the standard player markets:
- Standard NFL player markets: the player must take at least one snap. If he is active but plays no snaps, contracts settle at the last fair price before the game started, not at zero and not as a refund of what you paid.
- Late scratches: Kalshi has settled such markets at the fair price from before the absence was announced, so traders who rushed to bet against the player after the news gained nothing.
- In-game injury: if the player takes the field and then gets hurt, the contract settles on his actual statistics. Standard markets offer no protection for that.
- Protected player markets: in October 2026 Kalshi introduced NFL player markets that settle at the fair price if the player does not see the field. Check which kind you are trading.
Settling at a fair price means you can still gain or lose relative to your entry, depending on where the price was. Always check the specific market's rules for other sports and other contract types.
Postponed games and revised data
- Postponements: sports contracts name a deadline; what happens after it is in the rules and varies by market.
- Economic data: contracts usually settle on the first published figure, even if it is revised later. Check the rules for your market.
How Polymarket resolves markets: the UMA oracle
Polymarket does not decide outcomes itself. It uses UMA's Optimistic Oracle, a system that assumes a proposed answer is right unless someone challenges it:
- Proposal: after the event, anyone can propose the outcome by posting a bond, typically $750. A wrong or premature proposal loses the bond.
- Challenge window: for two hours, anyone can dispute the proposal by posting a matching bond.
- No dispute: the market resolves as proposed. This is how the vast majority of markets settle.
- Dispute: a second proposal round starts. If that is disputed too, the question goes to UMA's Data Verification Mechanism, a vote of UMA token holders that takes a few days. The winning side gets its bond back plus part of the loser's.
When the market resolves, winning shares are worth $1 each and you redeem them for collateral in your balance. Some rules include a 50-50 outcome for situations where no answer applies, in which case each share pays 50¢. Polymarket can also add clarifications to a market's rules when something unforeseen happens.
Why Polymarket disputes make headlines
The oracle works well for clear outcomes. It struggles when the wording is ambiguous or when UMA voters have money on the market themselves. In 2025, disputed markets on a US–Ukraine minerals deal and on whether Volodymyr Zelensky would wear a suit drew heavy criticism of the token vote, and UMA tightened the rules on who can propose outcomes. The lesson for traders: ambiguous questions carry a dispute risk that the price may not reflect.
Kalshi vs Polymarket resolution
| Kalshi | Polymarket | |
|---|---|---|
| Who decides | Kalshi, using the named source | UMA Optimistic Oracle; disputes go to a UMA token-holder vote |
| Speed | Usually soon after the source publishes | Two-hour challenge window if no dispute; days if disputed |
| Player does not play | Settles at a fair price under the market's rules | Depends on the market's rules |
| Changes after the fact | Rare | Clarifications can be added to rules |
| Regulator | CFTC | Polymarket US: CFTC; global site: none |
How to protect yourself
- Read the rules before you trade, especially the source and the deadline.
- Avoid ambiguous questions near resolution unless you are paid for the risk.
- Do not bet on what "obviously" happened if the named source might say something different, or might be late.
- Price in settlement risk on long or complicated markets: a few cents of discount can be fair.
- Keep records of rules as they were when you traded, in case of a dispute.
Market resolution: frequently asked questions
Does Kalshi have injury protection?
Standard player markets do not: if a player gets hurt during the game, contracts settle on his real statistics. If he is active but plays no snaps, standard NFL player markets settle at the last fair price before kickoff. Kalshi's newer protected NFL player markets settle at a fair price if he never takes the field.
Does Kalshi void bets on injured players?
Not like a sportsbook. Instead of refunding, Kalshi settles affected contracts at a fair price set by the market's rules.
Who decides Polymarket outcomes?
UMA's Optimistic Oracle: a bonded proposal that anyone can dispute within two hours, with disputed questions decided by a UMA token-holder vote.
How long does Polymarket take to resolve?
At least two hours after a proposal if no one disputes it; several days if a dispute goes to a vote.
