A study by the Anti-Corruption Data Collective (ACDC) indicates potential widespread insider trading issues on the prediction market platform Polymarket. The research analyzed 435,000 settled markets and $54.4 billion in trading volume from January 2021 to mid-March 2026, revealing unusually high success rates for low-probability bets, particularly in markets related to government military decisions. These findings suggest that insider information may be influencing outcomes, with some military-related contracts showing success rates exceeding 50%. The report highlights that profits on Polymarket are concentrated among a small group of traders. Research from London Business School and Yale University found that about 3% of traders were responsible for most price discovery, while Solidus Labs noted that less than 1% of wallets captured nearly half of all profits. ACDC recommends Polymarket enhance identity verification, implement conditional payouts for suspicious bets, and limit markets influenced by a few individuals. The report also calls for a public debate on the ethics of betting on sensitive events.