One week out, prediction markets see Democrats as favored to sweep Congress

The 2026 U.S. midterm election will be held a week from Tuesday, with the Republican Party looking to defend majorities in both the House and Senate , though Democrats are seen as two-to-one favorites to flip both chambers blue on prediction markets . Speculators on platform Kalshi place a 63% chance that Democrats win control of both the House and Senate. Those odds have stayed relatively stable since the beginning of October. Meanwhile, there's just under a 10% chance that Republicans sweep both chambers, and a 29% chance Democrats win the House while the GOP maintains its majority in the Senate. Contracts on the market are resolved using official data from the U.S. Congress.