Contentious Bet on Polymarket

A contentious $7 million bet on the prediction platform Polymarket has sparked disagreement between the Polymarket and UMA communities.

The bet speculated on whether Ukraine would agree to a mineral deal with U.S. President Donald Trump before April, with the “yes” probability surging from 9% to 100% between March 24 and 25, despite no official agreement being reached.

Polymarket relies on UMA, an optimistic oracle system, to determine the outcomes of its prediction markets. In this system, anyone can propose a resolution by staking a $750 USDC.e bond, which can then be challenged. If a dispute arises, UMA token holders vote to settle the matter.

In this case, the bet resolved as “yes,” leading many users to suspect manipulation by a “UMA whale”—a holder of a large number of UMA tokens capable of influencing the vote.

Polymarket responded via its Discord server, admitting the resolution was unexpected but denying it constituted a “market failure” that would warrant refunds. It clarified that the market was resolved too soon, as no deal between Ukraine and the U.S. has been confirmed, yet it stood by the UMA voting process to correct the outcome.

Polymarket has since turned to its community for suggestions on preventing future issues, promising clearer rules and forthcoming updates, though it has yet to detail specific changes.