The US House Committee on Oversight and Government Reform has launched an investigation into cryptocurrency prediction platforms Polymarket and Kalshi over concerns tied to insider trading and politically sensitive bets. Committee Chairman James Comer sent letters to Polymarket CEO Shayne Coplan and Kalshi CEO Tarek Mansour requesting internal documents related to how both companies monitor and prevent insider trading activity. Lawmakers are increasingly concerned that government officials or politically connected individuals could be using nonpublic information to profit from prediction markets.
The investigation follows reports that users placed large bets related to Israeli military action against Iran, Donald Trump's ceasefire announcement, and several congressional election events before key developments became public. Prediction markets have grown rapidly in recent years, allowing users to trade contracts tied to political events, geopolitical conflicts, and economic outcomes.
Investigation Details
Members of the House Committee on Oversight and Government Reform cited specific concerns about market integrity. The investigation was triggered by reports of suspicious trading activity tied to geopolitical events and political developments that occurred before public announcements.
Both platforms have already taken steps to address potential risks. In March, Polymarket updated its policies around suspicious trading activity and market integrity. Kalshi blocked three US politicians from betting on the outcomes of their own elections.
Company Responses
A Polymarket spokesperson said the platform maintains a "comprehensive market integrity system" and plans to cooperate with lawmakers during the investigation.
Kalshi defended its compliance framework, stating that the company has implemented "comprehensive insider trading protections" and intends to engage with Congress.
DOJ Criminal Case
The Congressional investigation arrives as the US Department of Justice continues pursuing a separate criminal case tied to prediction market trading. In April, federal prosecutors charged Staff Sergeant Gannon Ken Van Dyke, who allegedly used classified information connected to an operation involving Venezuelan President Nicolás Maduro to trade contracts on Polymarket.
According to investigators, Van Dyke earned more than $400,000 by using confidential government information before the events became public. He later pleaded guilty to charges tied to fraud and the unlawful use of confidential government information for personal gain.
The court released Van Dyke on $250,000 bail with travel restrictions limiting him to North Carolina, California, and New York while the case continues.
Regulatory Implications
The investigation highlights a growing legal and ethical debate surrounding prediction markets and insider information. Unlike traditional financial markets, prediction platforms are designed to aggregate information from participants who may hold unique insights into real-world events. Regulators now face a question about where legitimate informed trading ends and illegal insider trading begins.
Congress is seeking internal records from both Polymarket and Kalshi to evaluate whether their safeguards are strong enough to prevent misuse of sensitive information. The outcome of both the Congressional investigation and the DOJ case will influence how prediction markets operate under future US regulation.
