2026 Midterms: Control of Congress Odds
Prediction markets assign a 44.5% chance to Democrats controlling both the Senate and the House after the 2026 midterms, a close to a coin flip proposition. The odds for a Republican Senate with a Democratic House sit at a similar level.
2026 Balance of Power: D Senate, D House
Updated · Volume $8.6M
| Outcome | Probability | 24h |
|---|---|---|
| 2026 Balance of Power: D Senate, D House | 44.5% | +1.0 |
| 2026 Balance of Power: R Senate, D House | 40.5% | 0.0 |
| 2026 Balance of Power: R Senate, R House | 14.5% | 0.0 |
| 2026 Balance of Power: D Senate, R House | 1.8% | -0.3 |
| 2026 Balance of Power: Other | 0.5% | -0.2 |
Democrats holding both chambers is close to a coin flip at 44.5%. A split with a Republican Senate and Democratic House is also close to a coin flip (40.5%), while a full Republican sweep is unlikely (14.5%). All other outcomes are remote possibilities.
Context
The 2026 US midterms will decide whether the Democratic or Republican party controls each chamber of Congress. In the House, a majority of voting seats secures control. For the Senate, a party must hold more than half of voting members, or exactly half if the vice president—who breaks ties—belongs to that party. Should either outcome prove ambiguous, the market resolves according to the party affiliation of the first Speaker of the House or Senate Majority Leader selected after the election. The resolution sources are the Associated Press, Fox News, and NBC; the market settles once all three outlets have called both chambers, or based on official certification if they disagree. At present, a Democratic sweep of both chambers is priced at 44.5%, placing it in close to a coin flip territory. The alternative split outcome—Republican Senate, Democratic House—commands 40.5%, roughly even odds. A Republican clean sweep is unlikely, at 14.5%. The remaining configurations are distant outliers. The forecast for a Democratic Congress has edged +1.0 pts over the past day. Trading volume has reached $8.6M. The market is set to resolve by Nov 3, 2026.
FAQ
How is control of the House determined?
A party must win a majority of voting seats in the House of Representatives.
How is control of the Senate determined?
A party controls the Senate if it secures more than half of voting members, or exactly half and the vice president is from the same party.
What happens if the election result is disputed or ambiguous?
If control of either chamber is unclear under the standard rules, the market resolves based on the party affiliation of the first Speaker of the House or Senate Majority Leader chosen after the election.
When will this market resolve?
It resolves once the Associated Press, Fox News, and NBC have all called the winners of both chambers. If the three sources disagree, official certification decides.
Which parties are covered?
Only the Democratic and Republican parties. Independent candidates are assigned a party based on their most recently expressed caucus intention at the time the elections are called.
Data: Polymarket · Methodology · Not financial advice