Polymarket settles many of its prediction markets through UMA’s Optimistic Oracle: someone proposes the outcome, and anyone can dispute it during a short challenge window. We counted how often that happened in 81,348 closed Polymarket markets with at least $100,000 of lifetime volume whose resolution trail we could read on 27 October 2026. In 856 of them, or 1.05%, the trail records at least one dispute. The share rises with size: 0.6% for markets with $100,000 to $300,000 of volume, 2.5% for $1 million to $10 million, and 12.8% (90 of 701) above $10 million. The data come from Polymarket’s public Gamma API, which lists each market’s resolution statuses in order.
What a dispute means here
According to Polymarket’s resolution documentation, a proposal has a two-hour challenge period. A first dispute starts a new proposal round, and a second dispute sends the question to a vote of UMA token holders, which takes about 48 hours after a debate period; a disputed market therefore takes four to six days to resolve. Two or more dispute entries appear in the trail of 412 markets (0.51% of the sample), including 74 of the 701 markets above $10 million (10.6%). A dispute is not proof that a proposal was wrong: it means someone posted a counter-bond, and in a first round the original answer can be proposed again and stand.
Big markets, big disputes
Disputed markets account for $5.47 billion of the $68.96 billion of lifetime volume in the sample (7.9%), far above their 1.05% share by count. The largest disputed markets are about geopolitics and finance: MicroStrategy selling any Bitcoin by 31 May 2026 ($375.8 million), US forces entering Iran by 30 April ($269.0 million) and whether Zelenskyy would wear a suit before July, closed in July 2025 ($242.2 million), whose trail records five disputes. Large markets have more money riding on a close call and more traders watching the proposal, which is the likely reason for the pattern, though the data do not show motive.
Fewer disputes lately
By closing month, the dispute share peaked at 3.6% in May 2025 (49 of 1,368 markets) and ran at 0.4% to 0.6% from August to October 2026. Across the 90 days to 27 October, 90 of 17,881 markets (0.50%) were disputed, against 355 of 32,027 (1.11%) in the 180 days from 28 October 2025 to 27 April 2026. The sample is by volume, so it does not say whether this reflects clearer market wording, more careful proposers or a different mix of markets.
Key facts
Source: Polymarket Gamma API /markets (closed markets, volume of $100,000 or more), field umaResolutionStatuses; 111,605 markets pulled on 27 October 2026 (18:22 UTC).
Sample: 81,348 markets with a UMA proposal in the trail, closing between 29 March 2025 and 27 October 2026; $68.96 billion lifetime volume.
Disputed (one or more): 856 (1.05%): $100-300k 287 of 45,404 (0.63%), $300k-1m 230 of 25,417 (0.90%), $1-10m 249 of 9,826 (2.53%), $10m+ 90 of 701 (12.84%).
Two or more disputes: 412 (0.51%).
Left out: 30,255 markets with no proposal trail (the API does not say how they were resolved), markets under $100,000 and markets still open. Disputes recorded on the UMA protocol directly, outside Polymarket’s data, are not covered.
How to read it
The trail shows what happened, not whether the final answer was right, and selection matters: the sample contains only markets that reached $100,000, so the dispute rate for small, thinly traded markets is unknown. The statuses also depend on how Polymarket’s API records repeated events, so we count markets with a dispute entry rather than total disputes.
Why it matters for GambleFi
Resolution rules are part of the product on a prediction market, just as game rules are on a crypto casino, as our game mechanics guide explains for iGaming tokens and GambleFi platforms. For the size of the venue behind these markets see our venue volume count and the category split of Kalshi and Polymarket volume, and for more figures the statistics page. This is a data report, not investment advice.