Disputed bets are a growing headache for prediction markets, including Polymarket, as they contend with a surge of new traders and dizzying growth in trading volume. The platforms aim to write clear yes-or-no questions for traders to wager on. But the messiness of real-world events means it isn’t always obvious which side was right. Most prediction-market firms, such as Kalshi, sort out disputes and ambiguities themselves. But Polymarket outsources the task to a third-party service called UMA, which conducts votes when rival factions of traders disagree over who deserves a payout.