House Oversight Committee investigates potential insider trading on Polymarket and Kalshi

The House Oversight and Government Reform Committee is now poking around inside the prediction market industry, and the questions it’s asking are not comfortable ones. Rep. James Comer, the committee’s chair, sent letters to Polymarket CEO Shayne Coplan and Kalshi CEO Tarek Mansour on May 22, requesting internal compliance records tied to trades that may have been informed by nonpublic government intelligence.

The trades that triggered the probe

A US Army soldier was charged earlier in 2026 with allegedly using classified information about the capture of Venezuelan President Nicolás Maduro to rack up more than $400,000 in profits on Polymarket. Records show roughly 80 trades on Polymarket connected to the investigation that carried a 98% win rate.

Comer’s letters to both CEOs demanded user identity verification records and detailed information surrounding trades linked to the Maduro capture and the conflict in Iran. Congress wants to know who was trading, whether those traders had government clearances, and whether the platforms had any systems in place to catch this kind of activity before it became a federal investigation.

During an appearance on CNBC’s Squawk Box, Comer laid out his concern plainly. Government employees, by the nature of their work, have access to information that the rest of the market doesn’t. When those employees take that information and place bets on prediction markets, it’s functionally no different from a corporate executive trading their company’s stock ahead of an earnings announcement.

A $51 billion industry under the microscope

Trading volumes across the sector hit $51 billion in 2025. Polymarket became a household name during the 2024 US presidential election, when its markets were widely cited as real-time indicators of candidate viability. Kalshi has been carving out its own space as a CFTC-regulated platform offering event contracts on everything from economic data releases to weather events.

The committee chair has already hinted at potential legislative measures aimed at restricting government personnel from participating in prediction markets. Federal employees are already subject to restrictions on stock trading, financial disclosures, and various conflict-of-interest rules.

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