Bipartisan senators press Kalshi and Polymarket on preventing insider trading in election bets

October 30: According to The Defiant, U.S. Democratic Senator Elizabeth Warren and Republican Senator John Curtis sent letters to prediction market platforms Kalshi and Polymarket asking them to explain how they will prevent insider trading and market manipulation in election betting ahead of next week's midterm elections, and to provide the number of suspected violations intercepted before trades took place and those discovered afterward, with written replies due by November 3. According to The Block, the two said in the letters that they remain skeptical about whether the two companies can adequately police such event contracts with effective review and meaningful accountability.