U.S. House oversight chair expands insider trading probe into Polymarket, Kalshi

James Comer, chairman of the U.S. House Committee on Oversight and Government Reform, has expanded a congressional investigation into insider trading allegations involving prediction market platforms Polymarket and Kalshi, CNBC reported. Comer had launched the probe in May, requesting materials from Polymarket and Kalshi related to user identity verification, enforcement of geographic restrictions, and the detection of unusual trading activity.