The House Oversight Committee opened an insider trading investigation in prediction markets, announced by Chair James Comer. He sent letters to Kalshi CEO Tarek Mansour and Polymarket CEO Shayne Coplan seeking documents on KYC standards, detection policies for suspicious trades, reputation analysis, and deliberations over war‑related wagers. The probe includes internal communications about wagers on the Iran war and America’s attack on Venezuela, follows the arrest of a U.S. soldier accused of placing Polymarket bets with classified information, and notes Kalshi fined U.S. politicians for betting on their own elections.
The overview sets out the Oversight Committee’s announced inquiry and its principal document requests. It identifies the internal communications and incidents the committee flagged for review.
A New York Times investigation identified more than 80 instances of potential insider trading on Polymarket, and platforms have reported individual episodes that prompted internal reviews and public scrutiny. Both Kalshi and Polymarket say they are taking steps to root out insider traders and to reassure regulators, and industry reporting has highlighted a pattern of suspicious wagers and the arrest of individuals accused of using non‑public information. The evidence compiled by journalists and regulators has focused on trades that appear to exploit privileged knowledge and on whether platform detection and KYC processes were adequate to catch them.
Congressional and regulatory attention has increased in response to those findings. The Senate Commerce Committee held a hearing scrutinizing prediction markets, and the Senate unanimously passed a resolution banning members and staff from trading on these platforms. Bernstein projected that trading volumes could reach roughly $1 trillion by 2030, noting about $51 billion in volumes last year and roughly $240 billion projected for 2026, figures cited in industry analyses and market commentary.
The documented instances of potential insider trading and the industry growth projections have driven heightened oversight and legislative action. Lawmakers and regulators have publicly questioned whether existing controls are sufficient given the markets’ rapid expansion.
Both Kalshi and Polymarket have said they are taking steps to root out insider traders and to reassure regulators. Chair James Comer sent letters to Kalshi CEO Tarek Mansour and Polymarket CEO Shayne Coplan requesting documents on know‑your‑customer standards, detection policies for suspicious trades, analysis of insider trading scandals on the companies’ reputations, and deliberations regarding war‑related wagers. Industry and regulatory scrutiny has focused on the adequacy of platform detection systems and KYC controls. An industry observer said, “But they’re making a push to show they have the [detection] technology, and they are able and willing to use it.”
Regulatory attention has included a Senate Commerce Committee hearing that scrutinized prediction markets and a Senate resolution that unanimously banned members and staff from trading on those platforms. Lawmakers and commentators expressed concerns about potential exploitation and insider advantage, with one official saying, “This growing pattern of insider trading activity on prediction market platforms indicates that Congressional action may be necessary.” Another commentator asked, “If they can catch this guy, why can’t you catch another?” Public commentary also warned that government employees and members of Congress could use nonpublic information to profit, stating, “There’s a concern now that members of Congress, members of the president’s administration, any type of government employee, can use basic insider knowledge and make huge profits on anything government-related.”
Company assurances about enhanced detection and public statements from lawmakers have framed the ongoing regulatory debate. Oversight has concentrated on detection capabilities and conflicts of interest among market participants.
The House Oversight Committee investigation continues into alleged insider trading on prediction markets, focusing on Kalshi and Polymarket and prompted by concerns including a New York Times finding of numerous potential cases, the arrest of a U.S. soldier accused of using classified information to place Polymarket bets, and reports that Kalshi fined U.S. politicians for betting on their own elections. Congressional and regulatory scrutiny has included letters from Oversight Chair James Comer seeking documents on KYC standards, suspicious-trade detection policies, reputation effects and war-related wagers, a Senate Commerce Committee hearing, and a unanimous Senate resolution barring members and staff from trading, while both companies say they are taking steps to detect and prevent insider trading.
