Update (May 22 at 7:40 pm UTC): This article has been updated to include statements from Polymarket and Kalshi.
The chair of the US House of Representatives’ Oversight and Government Reform Committee sent letters to the CEOs of Kalshi and Polymarket, questioning the companies’ response to incidents of insider trading on the platform.
In a Friday X post, Committee Chair James Comer confirmed reports that he had sent letters to Polymarket CEO Shayne Coplan and Kalshi CEO Tarek Mansour, asking them for internal records on how the companies were handling insider trading. The Kentucky lawmaker said there were concerns in Congress over elected officials using “basic insider knowledge” to profit off the government’s actions.
“More than 80 suspiciously timed trades were placed ahead of Iran military operations,” said Comer. “Politicians and government officials with inside information are placing bets and taking profits. This insider trading must end.”
Source: James Comer
The “suspiciously timed trades” to which Comer was referring included those from a May 13 New York Times report, detailing incidents of prediction market users betting on Israel’s military actions against Iran, US President Donald Trump announcing a ceasefire in the country’s war with Iran and event contracts related to congressional elections.
Polymarket said in March that it had updated its approach to potential insider trading on the platform, while Kalshi announced in April that it had banned three US politicians for betting on their own races.
Related: Polymarket team says user funds safe as exploit losses climb above $600K
A Polymarket spokesperson said that the platform “maintains a comprehensive market integrity framework” and it would engage with Comer and the committee on the company’s transparency. A spokesperson for Kalshi said that the company was “proud of [its] comprehensive protections against insider trading” and would likewise engage with US lawmakers.
US soldier who allegedly profited from Venezuela bet still in court
In April, the US Justice Department announced a criminal indictment against Master Sergeant Gannon Ken Van Dyke, a soldier who was involved in the military operation that led to the capture of Venezuelan President Nicolás Maduro. Prosecutors alleged that Van Dyke used event contracts on Polymarket related to Maduro’s capture to profit by more than $400,000 using classified information.
Van Dyke pleaded not guilty to the charges, which included commodities fraud and the unlawful use of confidential government information for personal gain. He was released on $250,000 bail and limited to traveling between areas of North Carolina, California and New York.
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