Prediction Markets Signal Democratic Gains in 2026 Midterms

As the 2026 midterm elections see Americans cast their votes, prediction markets have converged on a clear assessment: Democrats are strongly favored to win control of both chambers of Congress, while Republicans confront an increasingly difficult battleground map in the fight to preserve their Senate majority. On Election Day, the two largest US-based prediction platforms, Kalshi and Polymarket, assigned Democrats roughly a 74 to 79 percent probability of taking control of the Senate, with comparable or higher odds attached to a House flip.