Polymarket First Half-Year Trading of Around $200 Million Flagged as Potential Insider Trading

BlockBeats News, July 21st. According to Bloomberg, as prediction markets like Polymarket and Kalshi expand, the issue of betting based on non-public information or information advantage is facing increased scrutiny. Bloomberg Businessweek analyzed approximately 34,000 potential insider trades marked by Polysights between August 2025 and June 2026; these trades exhibited characteristics such as new account creation, low-probability entries, large bets, or high trade concentration, but this alone could not determine rule violations by the traders.

The data shows that from January 1st to June 30th this year, the suspicious trading volume marked on Polymarket amounted to around $200 million, with a significant increase in abnormal trading volume being driven by geopolitical and war-related markets. Profits from potential insider trading are highly concentrated, with the top 1% of profit wallets receiving over half of the gains, and 57% of the related wallets being created less than 24 hours before the trades.

Some traders are reducing the likelihood of detection by using multiple associated wallets and splitting orders. For instance, 38 associated addresses placed bets in 90 geopolitical markets related to Iran and Venezuela, with a win rate of 98%, totaling $1.6 million in profits, and withdrew funds through the same Coinbase deposit address.

Polymarket stated that it monitors insider trading and other illicit activities and has so far referred nearly 100 wallets to law enforcement. Kalshi has also enhanced identity and employment checks and restricted individuals such as political candidates and athletes who could influence outcomes from participating in relevant markets.