Rep. James Comer expands investigation into prediction market insider trading

Rep. James Comer, the Kentucky Republican who chairs the House Oversight and Government Reform Committee, launched a congressional investigation on May 22 into potential insider trading on prediction market platforms, initially targeting Polymarket and Kalshi. Comer’s initial document requests targeted Polymarket CEO Shayne Coplan and Kalshi’s leadership, asking for compliance records related to identity verification, trade restrictions, and logs of anomalous trading activity. The deadline for those documents was set for June 5.

The trades that triggered the probe

Investigators identified more than 80 trades on Polymarket that appeared to anticipate major geopolitical events before they became public knowledge. One trader managed to net nearly $1 million with a 93% success rate on bets tied to US military actions in Iran, placing wagers just hours before strikes were announced.

The most concrete case so far involves Army Master Sgt. Gannon Ken Van Dyke, who was federally indicted in April 2026 for allegedly using classified information about a Venezuela operation to profit approximately $409,881 on Polymarket.

Legislation on the horizon

Comer has signaled plans to propose legislation that would explicitly bar government employees from trading on prediction markets related to government actions using insider knowledge. Federal insider trading laws and ethics regulations already prohibit government employees from profiting off non-public information, but prediction markets exist in a regulatory gray zone. The Commodity Futures Trading Commission has only recently begun to formalize oversight of platforms like Kalshi.

Rep. Chris Pappas and other Democrats pushed for subpoena authority as early as May 11, more than a week before Comer formally launched the probe.