Odaily Planet Daily reports that researchers from Columbia Law School and the University of Haifa analyzed the majority of Polymarket’s trading data from 2024 to 2026 and found that over 210,000 suspicious transactions generated $143 million in profits for "insider" traders. The study, published this month, is the first to estimate the total profits gained by suspicious accounts.
Researchers used five criteria related to trading timing and bet size to identify accounts that placed large bullish bets shortly before news releases. The study defines these activities as "informed" trading rather than "insider" trading, as some of the flagged large trades occurred in markets influenced by multiple factors, such as those related to the 2024 U.S. election. Of the top 20 most suspicious trades identified, most were linked to the outcome of the 2024 election, generating approximately $16 million in profits, while the rest involved Federal Reserve decisions and sporting events.
Rutgers University statistics professor Harry Crane questioned the methodology, arguing that its suspiciousness ranking overly relies on profitability. The study’s authors acknowledged that the method may have over- or under-included certain factors and characterized the identified volume of suspicious transactions as a "conservative lower-bound estimate of abnormal profits."
Earlier this month, Polymarket announced a ban on trading using "stolen confidential information" and "illegal tips," but its offshore exchange does not collect identity information such as users' names, making enforcement unclear.