Betting or Reality? Polymarket prediction market accused of manipulation, "UMA Whale" sparks a Crisis of Confidence.

Although the encryption prediction platform Polymarket is considered a significant example of a "landing application", a recent viral post on X (formerly Twitter) accused the platform of being manipulated by "UMA Whales". Two markets involving tens of millions of dollars in bets have become the center of controversy, and users are questioning the authenticity of Polymarket's Decentralization.

Concerns arise over the market prediction being a "setup", with two major betting topics becoming the center of controversy.

A user @tatethebrand posted a long article on X, revealing a series of controversies surrounding Polymarket. The post includes screenshots of two popular betting questions: whether Iran's Fordow nuclear facility will be destroyed by the end of June 2025, and whether Ukrainian President Zelensky will wear a suit before July. These two markets attracted approximately $23.5 million and $15.4 million in wagers, respectively, but the outcomes sparked public outrage.

In the Fordow gamble, the market once predicted a probability of "being destroyed" as high as 99% before the end of June. According to updates from Al Jazeera and Wikipedia, the U.S. B-2 bombers struck the facility on June 15, but the International Atomic Energy Agency (IAEA) stated the next day that "no significant damage was observed," as Iran had evacuated the facility staff in advance. To date, the IAEA has not officially made a determination, leaving the market in limbo and raising questions of speculation and information asymmetry.

As for the betting question of whether Zelensky wore a suit, even though the Kyiv Post published a photo of him in a suit on June 25, Polymarket ultimately ruled the result as "no." This decision was finalized by a vote from the UMA community, where the majority of UMA holders chose "No," leading many users to question whether the platform was "taking sides" in the face of facts.

Concentration of control? UMA Whale accused of manipulating market direction

@tatethebrand's post accuses Polymarket of being superficially decentralized but actually dominated by a few UMA token holders. These "Whales" can control market outcomes through the voting mechanism, creating a monopoly-like situation. A 2025 arXiv study also points out that governance power is generally concentrated in the hands of a few people in multiple DeFi protocols, questioning the substantive meaning of decentralization.

In addition, a report by Mitrade in March of this year revealed a manipulation scandal amounting to 7 million dollars, mentioning that certain Polymarket validators influenced market trends by setting rules and coordinating votes. Although the report has not yet undergone academic review, it resonates with the current situation.

The post even likens the control structure of UMA to a "monopoly group," believing that a few individuals hold voting power, appearing decentralized on the surface, but in reality, it is centralized governance. Although there is no clear evidence showing that UMA is subject to organized manipulation, the concentration of token holders is concerning, and users are starting to question the fairness of the platform.

What is the relationship between Polymarket and UMA?

Polymarket is a decentralized blockchain prediction market platform, whose prediction results heavily rely on the UMA protocol as the core data source and adjudication mechanism. Specifically, when settling markets, Polymarket submits the event results to the UMA optimistic oracle, where UMA token holders participate in collective voting and arbitration to ultimately determine the settlement results of the bets. This design allows for decentralized and transparent result verification, but it has also sparked controversy due to large holders or a minority exploiting the governance weight of the UMA oracle. As the number of Polymarket users and trading volume increases, the demand for the UMA oracle grows in tandem, forming a close and interdependent technical and economic relationship between the two.

Users are furious, and competing platforms are taking advantage of the situation.

As the controversy brews, Polymarket is conducting a fundraising round led by Peter Thiel's Founders Fund, with a target valuation of $1 billion.

There are also voices of division within the encryption community. The well-known trader defipolice stated that Polymarket is no longer a "platform for predicting the truth," but rather "a scripted gambling game." Many users claim to have lost hundreds of thousands of dollars in the Zelensky betting game.

( aims at Polymarket! Paradigm leads the investment in Kalshi's funding of 185 million USD, with a valuation looking at 2 billion ).

The road ahead is unclear, and Polymarket's trust crisis awaits resolution.

As the deadline for the Fordow bet approaches and the IAEA has not provided a clear response, market attention will shift to the response mechanisms of UMA and Polymarket. Although blockchain tools like Etherscan can track voting and holding addresses, interpreting the data still requires professional analysis.

Currently, Polymarket has not publicly responded, but the co-founder of UMA has hinted at adjusting the relevant decision-making processes to reduce centralization risks.

For users, this incident serves as a wake-up call: before participating in the encryption prediction market, it is essential to understand the governance structure and risk distribution behind the platform. Whether it is truly decentralized has become the core issue of greatest concern for users.

Is this article a gamble or the truth? Polymarket's prediction market is accused of being manipulated, with "UMA Whale" triggering a crisis of trust, first appearing in Chain News ABMedia.