Report: Polymarket may have broader insider trading issues, with a small number of wallets capturing most of the profits

According to Odaily, a new report from the non-profit research organization Anti-Corruption Data Collective (ACDC) indicates that the prediction market platform Polymarket may be facing more widespread insider trading issues than previously known, such as those found in the “Green Beret Bet on the Venezuela Raid” incident. After analyzing 435,000 settled markets and $54.4 billion in total trading volume from January 2021 to mid-March 2026, the study found that low-probability bets in markets related to government decisions, such as military and defense, had abnormally high win rates.

Data shows that the average success rate for such “long-shot bets” in political markets is around 14%, while in certain military-related contracts, the success rate exceeds 50%. The research suggests that it is difficult to predict outcomes in these markets based solely on public information, making them more susceptible to the effects of information asymmetry, including insider trading or professional informational advantages.

The report also notes that profits on Polymarket are highly concentrated. Research from London Business School and Yale University shows that about 3% of traders contribute the majority of the platform’s price discovery; blockchain analytics company Solidus Labs found that less than 1% of wallets captured around half of all profits.

For example, in the June 2025 US airstrike on Iran, in the few hours preceding the strike, 19 low-probability bets totaling $164,000 were concentrated into “YES” contracts that ultimately paid out. Eight wallets made a total profit of around $1.8 million, with nearly $500,000 gained by a single wallet. Although the Pentagon deliberately concealed the operation with decoy bombers and long-range stealth jets, a small number of traders still managed to accurately bet on the outcome.

ACDC recommends that Polymarket should strengthen identity verification, set conditional payouts for suspicious bets, limit markets where outcomes are decided by a small group, and reduce overly granular contract designs. The report further calls for broader discussion about whether the public should be able to bet on such events.