Prediction market traders now see nearly 75% chance of Democrats winning the Senate

Momentum for Democrats is building on Kalshi, with traders on Monday seeing a 74% chance of the party winning control of the Senate — the highest odds seen for the party on the platform since the market first opened. The higher odds come after a New York Times and Siena University poll found Democrats are leading in several battleground states, strengthening Democrats' path to a possible Senate majority. The contract asks, "Who will control the Senate?", and will be verified by the Library of Congress after Tuesday's vote. Since the market first opened in 2024, Republicans dominated the market for Senate control in 2026. The gap between the parties' odds narrowed shortly after the U.S. and Israel first launched strikes on Iran on Feb. 28, though the chances for Republican control jumped up to 60% in July before reversing in mid-September. Markets on separate Senate races have also seen major movement in favor of Democratic candidates in the last 24 hours. Traders on Kalshi now see a 74% chance of Democrats winning the Texas Senate race, up from 68.4%, over the past 24 hours. The Iowa Senate market jumped to 50% from 42% on Polymarket in favor of Democrats. In Kansas, which has not elected a Democratic U.S. senator since 1932, odds of Democratic candidate Adam Hamilton winning over Republican Roger Marshall are up to 63% from 52%. Odds and gambling platforms do not use methodologies used by traditional political polling, and therefore are not substitutes for political polls. Disclosure: CNBC and Kalshi have a commercial relationship that includes customer acquisition and a minority investment.