Traders Flip Senate Control Bet as Democrats Overtake Republicans on Kalshi, Polymarket
Prediction markets now give Democrats a slight edge, at 51%, to control the U.S. Senate after the 2026 midterms, marking a sharp reversal from a year ago when they were priced at just 18%. Republicans’ chances have dropped to 49%, with platforms like Kalshi and Polymarket reflecting this shift. On Myriad Markets, traders see the parties’ chances as evenly split. The rapid movement in probabilities accelerated over the last two weeks, coinciding with increased U.S.-Iran tensions and American military involvement. Despite initial expectations that Republicans would easily hold the Senate—given a favorable map for their party—recent geopolitical events have caused traders to reassess the outlook. Prediction markets, which allow participants to buy and sell contracts based on real-world outcomes, have often accurately reflected political shifts, including forecasting the 2024 presidential race. Trading volumes for Senate control contracts have risen, reaching over $2.3 million on Kalshi and nearly $900,000 on Polymarket. The closely priced contracts indicate traders anticipate a volatile and competitive Senate race, with global and domestic events likely to keep influencing expectations.
