The 2026 US midterm election prediction markets currently show a much clearer picture for control of the House than the Senate.
Kalshi and polymarket.com both price Democrats at close to 90% to control the House, while their Senate markets are much closer to an even split. That difference highlights where prediction-market traders see the most uncertainty ahead of November's election.
Prediction-market prices change as traders respond to polling, candidate speeches and activity, wider political updates and other developments that could affect an election. Different levels of trading activity and liquidity can also cause prices to vary between markets. Learn more about how prediction markets work in our explainer piece.
In this article, we look at what the latest prediction markets say about control of Congress, which Senate races are contributing to that uncertainty, and why Kalshi and Polymarket can produce different prices.
For the latest prices across individual Senate and governor races, see the iPredicta US Midterms prediction markets page.
- Polymarket figures in this article refer to markets on polymarket.com unless otherwise stated. polymarket.com and Polymarket US operate separate markets, so prices can differ between the two platforms. polymarket.com does not accept US residents.
What do prediction markets expect for Congress in 2026?
Prediction markets allow traders to buy and sell contracts based on the outcome of future events. The price of a contract is generally interpreted as the market's current estimate of the probability of that outcome.
For the 2026 midterms, the key markets ask which party will control the House and Senate after the election. Unlike a traditional poll, which measures voter preferences at a particular point in time, prediction-market prices can change as traders respond to the latest available information.
The current picture is notably different between the two chambers. The House market gives Democrats a much higher probability of taking control, while the Senate market remains much closer.
The two chambers have very different electoral maps, with different races deciding who takes control.
Polymarket's individual Senate markets show where some of that uncertainty is concentrated. Among its more actively traded Senate markets are Maine, Texas, Michigan and Alaska, with Ohio and Iowa also attracting significant trading activity.
Why is the Senate prediction market so much closer than the House?
The Senate and House have very different sets of races, meaning the path to control is different in each chamber.
The Senate market remains close because several individual contests are themselves relatively closely priced. A party can be strongly favoured in a number of states while still facing uncertainty over enough other races to leave control of the chamber close to 50-50.
The House market is different. All 435 House seats are up for election, so the overall market reflects expectations across a much larger number of individual contests.
Which Senate races are attracting the most trading activity?
A relatively small group of Senate races is attracting much of the trading activity on the Kalshi and Polymarket Senate prediction markets.
Texas, Michigan, Ohio and Iowa are useful examples because their prices range from relatively close contests to races with a clearer market favourite, and give us a useful cross-section of competitive Senate markets to analyse.
Selected high-volume Senate markets
| State | Kalshi | polymarket.com |
|---|---|---|
| Texas | James Talarico (D): 54% | James Talarico (D): 57% |
| Ohio | Sherrod Brown (D): 53% | Sherrod Brown (D): 54% |
| Michigan | Abdul El-Sayed (D): 64% | Abdul El-Sayed (D): 65% |
| Iowa | Ashley Hinson (R): 60% | Ashley Hinson (R): 60% |
Market snapshot: 15:41 UTC, 17 September 2026. Percentages represent current prediction-market prices and can change as trading continues.
The prices are broadly similar across the two platforms, with Texas the clear exception. Texas and Ohio are currently among the closest to a 50-50 market, while Michigan is more heavily priced towards the Democratic candidate and Iowa towards the Republican candidate.
For the full list of state-by-state latest prices and trading activity, see the iPredicta US Midterms prediction markets page.
What do the House prediction markets tell us?
The House prediction markets currently give Democrats a considerably higher probability of taking control of the chamber than the Senate markets do.
| Market | Kalshi | polymarket.com |
|---|---|---|
| Democratic control of House | 88% | 88% |
Market snapshot: 15:41 UTC, 17 September 2026.
Kalshi and polymarket.com agree on House control, both pricing it at 88%.
That does not mean the outcome of individual House races is certain. The overall market reflects expectations across hundreds of contests, and changes in competitive districts could move the headline price.
But for now the House market presents a much clearer picture than the Senate market.
Kalshi vs Polymarket: Where do the 2026 midterm markets disagree?
Kalshi and Polymarket currently give broadly similar readings on the 2026 midterms, although their prices are not identical.
In the chamber-control markets, the gap is in the Senate, where Kalshi currently prices Democratic control at 58%, compared with 59% on polymarket.com. The two venues agree on the House, both pricing Democratic control at 88%. Among the state markets, Texas shows the widest gap, with James Talarico at 54% on Kalshi and 57% on polymarket.com.
| Market | Kalshi | polymarket.com |
|---|---|---|
| Democratic control of Senate | 58% | 59% |
| Democratic control of House | 88% | 88% |
| Democratic sweep | 57% | 59% |
Market snapshot: 15:41 UTC, 17 September 2026. Prices can change as trading continues.
Separate markets are priced by separate traders and do not always add up. A sweep requires Senate control, so it can never truly be more likely, and when a sweep is quoted above Senate control the gap is telling you about two order books rather than about the election.
A difference between two prediction markets does not necessarily mean that traders have a fundamentally different view of the election. Each market has its own traders, liquidity and order book, while the timing of trades can also affect prices.
A market can also move on one platform before another as traders respond to new information. This can happen because the platforms have different levels of liquidity and different order books, so the same news may lead to more buying or selling on one platform before the other.
The differences can be more noticeable in individual state markets where trading activity is lower, because a smaller number of trades can have a greater effect on the market price.
The useful comparison is therefore not simply which platform has the higher price. It is where the markets differ, how large those differences are and what might explain them.
Learn how to spot and assess differences between Kalshi and Polymarket prediction markets in our guides section.
What could change the 2026 midterm prediction markets?
The current prediction-market prices are a snapshot rather than a fixed forecast of the election. They can change as new information becomes available, particularly in closely contested Senate races.
New polling, candidate activity, campaign events and major political or economic news could all affect prices. Changes in individual races could also feed into the wider markets for control of Congress. For how sharply these markets can move when news breaks, our piece on what the 2024 election taught us about midterm prediction markets traces the swings around Joe Biden's withdrawal and the televised debates.
That means the headline probabilities are likely to change as Election Day approaches. The individual state markets provide a useful way to see where those changes are happening and how they could affect the wider picture.
What do the 2026 midterm prediction markets tell us?
The current markets show a clear difference between the two chambers of Congress. Both Kalshi and polymarket.com put Democratic control of the House at close to 90%, while their Senate markets remain much closer.
The individual Senate markets show where some of that uncertainty is concentrated. The comparison between Kalshi and Polymarket also shows that two platforms can produce slightly different prices while broadly reflecting the same election picture.
For the latest 2026 midterm prediction-market prices, see the iPredicta US Midterms prediction markets page.
