Prediction markets on platforms like Kalshi and Polymarket now show a narrow lead for Democrats to win control of the U.S. Senate in the 2026 midterm elections. Contracts price the Democratic Party’s chance at roughly 51%, edging out Republicans at 49%. This marks a dramatic reversal from a year ago when Democrats had just an 18% implied probability. The shift accelerated in the past two weeks following the start of U.S. military involvement in Iran.
Political prediction markets have shifted to favor Democrats to control the U.S. Senate after the 2026 midterm election. This is the first time the party has taken a lead in the race’s history on platforms tracking the outcome.
Contracts on prediction platforms, including Kalshi and Polymarket, show Democrats with a roughly 51% chance of winning Senate control compared with 49% for Republicans. On Myriad Markets, traders are pricing the chances of a Democratic sweep at about 50-50.
“The Democratic Party is now favored to win the Senate for the first time in the race’s history,” said Jack Such, a Kalshi spokesperson. “The race is now essentially a coin flip, with Democrats having a 51% chance to win.”
The narrow lead represents a dramatic reversal from a year ago when markets priced Democrats at just an 18% probability. The shift reflects a steady repricing by traders over recent months that accelerated in the past few weeks.
According to Kalshi data shared by Such, the turnaround has been particularly sharp in the past two weeks. Since the start of American military involvement in Iran roughly 16 days ago, the Democrats’ implied probability has increased by about 11 percentage points.
Trading volumes on these markets remain relatively modest compared with traditional financial markets. Kalshi’s Senate control contract has generated more than $2.3 million in volume, while the equivalent market on Polymarket has seen close to $900,000 traded.
With the contracts now pricing the race as effectively even, traders appear to be bracing for a volatile political cycle. Small changes in polling, policy, or global developments could swing the balance of power in the chamber.
