House Oversight Probes Kalshi, Polymarket Over Trades

House Oversight Committee Chair James Comer sent letters to the CEOs of prediction market platforms Kalshi and Polymarket requesting internal records after reports of suspected insider trading, including more than 80 trades placed ahead of Iran-related military actions.

Comer posted on X that “More than 80 suspiciously timed trades were placed ahead of Iran military operations” and said Congress is concerned that politicians and government officials used privileged information to profit on prediction markets. The letters were addressed to Polymarket CEO Shayne Coplan and Kalshi CEO Tarek Mansour.

A May report described users placing wagers on military actions involving Israel and Iran, bets tied to a U.S. president announcing a ceasefire, and contracts linked to congressional elections. Polymarket updated its approach to potential insider trading in March. Kalshi announced in April that it had banned three U.S. politicians for betting on their own races. Neither company immediately provided a response to the committee’s inquiry.

The Justice Department indicted Master Sergeant Gannon Ken Van Dyke in April on charges that he used classified information to place event-contract bets related to the capture of Venezuela’s president, allegedly profiting more than $400,000. Van Dyke pleaded not guilty and was released on $250,000 bail with travel restrictions.

Comer’s letters seek internal records on how the platforms detect and respond to suspected insider activity, steps taken to prevent trading on nonpublic government information, and documentation tracing suspiciously timed trades. The committee requested platform policies, monitoring procedures and records of enforcement actions.

Prediction markets allow users to place bets on the outcome of political, military and other real-world events. Lawmakers and regulators are reviewing whether platform safeguards and industry practices are sufficient to prevent trading based on nonpublic government information.