Polymarket Overrules UMA Voters in Trump-Xi Call Market
A March 30 message in Polymarket’s market on who Trump will speak to in March sent one set of odds from 70% to 2%.
Donald Trump announced that he had spoken with Chinese President Xi Jinping over the weekend. However, China didn’t confirm the call, so there was no clear evidence that the two had spoken. The odds rose again after a UMA voter changed their vote to Yes, the two leaders spoke. The market then went into dispute.
On Monday, Polymarket clarified that “there is not a consensus of credible reporting that Trump has spoken to Xi in March.” It refutes the UMA voters that were supposed to form the backbone of Polymarket’s decentralized resolution process.
TheGreekTrader described the developments throughout the story.
UPDATE: Polymarket clarified this market. pic.twitter.com/Lso8a4udyu
— The Greek Trader (@TheGreekTrader) March 30, 2026
Polymarket’s intervention has disappointed some users who want a decentralized resolution system. One of Polymarket’s original pitches was a platform where no single authority could dictate what the truth was. But clamping down on incorrect resolutions is welcome for other traders frustrated that UMA whales have been making those same dictates.
However, Polymarket’s work on its resolution process may not assuage other concerns from U.S. regulators.
New Polymarket investigation
CNN reported that federal prosecutors had met with Polymarket representatives to discuss whether insider trading law violations had occurred on Monday.
The timing of trades on Venezuela’s capture were among the suspicious trades that prosecutors wanted to discuss. One user won $400,000 after trading on Nicolas Maduro’s removal from office and placed the trade hours before Trump announced his raid.
Polymarket faces no charges.
Polymarket has updated its rulebook regarding market integrity, and the industry is taking insider trading concerns more and more seriously.
NFL asks for prohibitions on certain prop bets
ESPN reported letters that the NFL sent to Kalshi and Polymarket asking them to not offer markets on events that can be easily manipulated. The NFL raised concerns about broadcast mention markets, celebrity appearances, and draft picks.
Prediction market venture capitalist Noah Zingler-Sternig proposed a compromise that would allow some of the markets the NFL opposes. However, these markets could have low position limits, making inside information difficult to profit from.
A really cool compromise would be to enforce strict trading limits on these events rather than outright ban them.
The NFL’s stance makes sense, but having information about which players will be drafted to which teams or which coaches will be fired or hired is very useful for… https://t.co/pIrftMZRAK
— Noah Zingler-Sternig (@Nostroah) March 31, 2026
This is one of the tensions between the prediction market industry and other industry leaders concerned about its growth. The two sides have yet to settle on which information should be made public and which should remain protected.