House Oversight Committee Probes Polymarket and Kalshi Over Insider Trading

House Committee on Oversight and Government Reform Chairman James Comer initiated an inquiry into prediction market venues Polymarket and Kalshi regarding potential insider trading by platform users ¹. In letters directed to Polymarket Chief Executive Officer Shayne Coplan and Kalshi Chief Executive Officer Tarek Mansour, the committee requested documentation detailing user identity verification, surveillance systems, and the enforcement of geographic restrictions ¹.

Lawmakers are evaluating the adequacy of existing corporate controls designed to prevent market participants from using nonpublic intelligence or evading domestic federal regulations through offshore access ¹. Comer stated that internal platform data remains essential to uncovering bad actors and assessing whether operators are fulfilling their regulatory mandates ¹. The congressional inquiry follows reporting that highlighted more than 80 Polymarket accounts executing well-timed wagers prior to undisclosed military actions involving the United States, Israel, and Iran ¹.

Scrutiny Over Political and Defense Wagers

The committee also cited domestic political wagering, noting that gubernatorial candidate Kyle Langford placed a $200 bet on his own election via Kalshi in May 2025, alongside three other political figures who wagered on their respective campaigns ¹.

Federal legal actions have escalated these concerns ¹. An indictment unsealed on April 24, 2026, alleged that U.S. Army Master Sergeant Gannon Ken Van Dyke leveraged classified operational intelligence concerning Operation Absolute Resolve—which resulted in the capture of Venezuelan President Nicolás Maduro—to generate over $409,000 in betting gains ¹. Comer warned that the recurrence of anomalous transactions suggests federal legislative action may be required to govern prediction venues ¹.