Polymarket, a popular prediction platform, is facing serious backlash after a $7 million market was allegedly manipulated by UMA whales . The controversy involves a market titled “Ukraine agrees to Trump mineral deal before April?” which resolved as “Yes,” despite there being no official confirmation from U.S. or Ukrainian sources . Users are calling it the biggest manipulation case in the platform’s history, accusing insiders of using their power to influence the vote outcome. The rules for the market clearly said the result would be based only on official government sources. However, the resolution ignored this condition, and the outcome favored the “Yes” side. Many users lost money, and the crypto community is reacting with anger and suspicion. According to one user on X, two previous markets with nearly identical rules ended with a “No” result—yet they involved far less money, under $400,000 combined. In contrast, this manipulated market involved more than $7 million. The user claimed that a powerful participant used multiple accounts and cast votes with 5 million UMA tokens, representing 25% of the total voting power , to tilt the decision in their favor. Polymarket’s team responded in their Discord channel but refused to offer refunds. They explained the issue was not a platform failure but a unique situation they aim to prevent in the future. They promised improved systems and monitoring, but the explanation did little to calm users who lost significant funds. This is not the first time Polymarket has been accused of insider control. A detailed thread by crypto user Folke Hermansen outlined past cases of similar manipulation. He alleged that Polymarket insiders often write vague rules, place bets themselves, and work with verifiers to rig outcomes. One example involved a market about gold being missing from Fort Knox, which resolved to “No,” resulting in a $3.5 million loss for those who bet otherwise. In another case, Hermansen said the dispute option was quietly disabled during a critical window, preventing users from challenging a “No” resolution in a tariff-related market. A third example was a market about whether Trump would say “China” during a crypto event. Even though he said it, Polymarket clarified the rule after the fact and ruled “No,” which appeared retroactive and unfair. Hermansen points out that the UMA system used to verify market outcomes is flawed. Just two whales allegedly control over half the voting power. One person alone reportedly holds 7.5 million of the 20 million staked tokens. These whales are not neutral—they also place large bets, giving them both the power to vote and financial reasons to sway results. He explained that UMA is supposed to reward truth-seeking, but it really encourages users to vote with the majority to avoid losing staked tokens . This creates a system where large holders lead the vote, and others follow to avoid losses. That means truth doesn’t matter as much as following the crowd. Adding to the problem, challenging a market outcome requires a bond, usually $750 USDC. Large holders can afford to challenge or propose outcomes easily, while smaller users can’t risk the money. This keeps control in the hands of the few, with most disputes ending in near-total agreement—sometimes over 95%. Finally, Hermansen noted that all voting and dispute actions are anonymous, making it impossible to trace who manipulated a market. That lack of transparency allows insiders to operate freely and avoid accountability. With users now questioning the fairness of its markets, Polymarket’s credibility is on the line. Unless changes are made, confidence in the platform—and its core system—could collapse.
