House Oversight and Government Reform Committee Chairman James Comer initiated a congressional inquiry into insider trading safeguards at prediction market platforms Kalshi and Polymarket on Friday. Comer sent letters to both platforms' chief executives requesting documents detailing identity verification procedures, geographic restrictions enforcement, and anomalous trading detection methods. The investigation was announced on CNBC's "Squawk Box" and focuses on trades linked to elections and U.S. military action in Venezuela and Iran. Comer stated his goal is to determine the extent of insider trading activity and develop legislation barring members of Congress, administration officials, and government employees from trading on prediction markets. Both Polymarket CEO Shayne Coplan and Kalshi CEO Tarek Mansour were instructed to produce requested documents and communications by June 5.
Documented Trading Incidents
The probe responds to multiple confirmed cases of suspicious trading activity. In April, a U.S. soldier was arrested for allegedly using inside information about the ouster of former Venezuelan leader Nicolas Maduro to place Polymarket bets totaling approximately $400,000. A New York Times investigation identified more than 80 Polymarket users who placed suspicious trades, including wagers made hours before U.S. and Israeli strikes on Iran.
Platform Actions and Compliance Measures
Both platforms implemented controls prior to the Friday announcement. Kalshi suspended three congressional candidates in April after they placed bets on their own races, violating company rules. Polymarket hired blockchain analytics firm Chainalysis in late April to detect insider trading and market manipulation as part of its effort to secure CFTC approval.
Legislative and Regulatory Context
Comer's investigation follows a May 11 letter to the Oversight Committee from seven Democratic lawmakers led by Rep. Chris Pappas of New Hampshire, requesting subpoenas of both platforms. Bipartisan legislation targeting prediction market insider trading has been introduced in the current Congress, with several bills specifically restricting trades by those with access to non-public government information.
Kalshi operates under CFTC regulation in New York and prohibits anonymous trading. Polymarket is licensed in Panama and operates its primary platform outside U.S. regulatory oversight, though it maintains a separate, limited CFTC-regulated product for domestic users.
