Report: Polymarket May Have Broader Insider Trading Issues, with a Handful of Wallets Capturing Most Profits

Odaily News According to the latest report from the non-profit research organization Anti-Corruption Data Collective (ACDC), the prediction market platform Polymarket may be facing a broader insider trading problem than previously indicated by the "Green Berets bet on Venezuela raid" incident. The research analyzed 435,000 settled markets with a cumulative trading volume of $54.4 billion between January 2021 and mid-March 2026, revealing abnormally high win rates for low-probability bets in markets related to government decisions, including military and defense matters.

The data shows that the average success rate for such "longshot bets" in political markets is about 14%, while some cases involving military contracts saw success rates exceeding 50%. The study concludes that these markets are difficult to predict based solely on public information and are more susceptible to information asymmetry, including insider trading or professional informational advantages.

The report also highlights a high concentration of profits on Polymarket. A study by the London Business School and Yale University indicates that approximately 3% of traders contribute to most of the platform's price discovery; meanwhile, blockchain analytics firm Solidus Labs found that less than 1% of wallets account for about half of the profits.

Taking the example of the US airstrike on Iran in June 2025, in the hours preceding the attack, 19 low-probability bets totaling $164,000 were concentrated on purchasing the "YES" contract that ultimately paid out. Eight wallets collectively profited about $1.8 million, with a single wallet making nearly $500,000. Despite the Pentagon using decoy bombers and long-range stealth fighters to deliberately conceal the operation at the time, a small number of traders accurately predicted the outcome.

ACDC recommends that Polymarket strengthen identity verification, implement conditional payouts for suspicious bets, restrict markets whose outcomes are determined by a small group, and reduce overly specific contract designs. The report further calls for a broader discussion on whether the public should be allowed to bet on such events. (CoinDesk)