Comer Opens Inquiry Into Polymarket, Kalshi Over Insider Bets

House Oversight Committee Chair James Comer has opened a formal inquiry into prediction market platforms Polymarket and Kalshi, sending letters to their chief executives requesting records related to insider-trading safeguards, internal discussions and know-your-customer procedures. The letters were addressed to Polymarket CEO Shayne Coplan and Kalshi CEO Tarek Mansour and ask for documents the committee says are needed to assess compliance with U.S. rules.

The committee requested written policies, communications about enforcement actions, records of internal investigations and details on customer verification and blocking mechanisms. The documents seek to show how the companies detect and prevent illegal trading and whether users can access offshore sites to evade U.S. oversight.

Comer opened the inquiry after reports linked more than 80 Polymarket accounts to trades placed shortly before military actions involving Iran. The inquiry also cited a case in which Gannon Ken Van Dyke, a U.S. service member who took part in an operation involving Venezuelan leader Nicolás Maduro, reportedly earned about $400,000 on Polymarket. The letters reference a separate instance in which Kyle Langford placed a roughly $200 wager on Kalshi tied to his own California election contest.

Comer called the current state of prediction markets “the wild west,” warning there are no clear rules governing the platforms. He also raised concern that government employees could use nonpublic information for profit and said the committee will examine whether existing protections are sufficient.

The Oversight Committee will review materials once produced and then decide whether to hold hearings or pursue legislation. Polymarket and Kalshi face parallel scrutiny from state regulators considering whether prediction markets should be treated as gambling products.

Prediction markets allow users to place wagers on political outcomes, economic indicators and other real-world events. Platforms contend they aggregate user views to forecast outcomes; critics contend weak controls can create opportunities for insider trading. The committee’s document requests aim to identify what controls exist and how they are applied in practice.