Prediction Markets Put Democratic Midterm Sweep Odds at 67%

Prediction markets are assigning a 67% probability to Democrats winning control of both the House and Senate in the 2026 midterm elections.
That is a sharp shift from roughly 24% at the same point last year.
On Polymarket, a Democratic sweep is currently the most heavily favored balance-of-power outcome, ahead of a split result where Democrats take the House while Republicans retain the Senate.
The repricing comes as Democrats have gained momentum across several competitive congressional races.
Election Day is November 3, leaving roughly one month for polling, campaign spending and individual Senate and House contests to move the market again.
Prediction-market probabilities are not election forecasts and can change quickly as new information arrives.
For markets, control of Congress matters because it could reshape expectations around fiscal policy, taxes, regulation and the ability of the White House to pass legislation during the second half of President Trump’s term.