Prediction market volume on the 2026 US midterm cycle has surged through the spring, putting the category on pace to rival the record set during the 2024 presidential election. Kalshi’s House and Senate control contracts have crossed nine-figure cumulative notional. Polymarket’s US midterm-adjacent contracts (cabinet shakeups, presidential approval, government shutdown odds) continue to set records each month. PredictIt’s loyal community has lit up state-level races that the larger platforms do not list.
What the markets are pricing
As of mid-April 2026, Kalshi’s most-traded political contracts cluster around three themes: Senate control after the November midterms, control of individual House seats in a handful of competitive districts, and the probability that the sitting administration’s approval rating crosses key thresholds before voters head to the polls. Implied probabilities reflect a tighter race than at the same point in past midterm cycles.
Polymarket’s globally accessible book runs parallel contracts on US politics that international users participate in heavily. Prices on the two platforms have stayed within a percentage point or two of each other on the highest-volume contracts, a sign that arbitrageurs are doing their job.
How to participate
For US residents, Kalshi is the regulated venue with the deepest US politics order books. For users who want comprehensive coverage of every competitive race including state-level contests, PredictIt is still the place to look. For international users, Polymarket offers parallel contracts with much broader global political coverage. Our best prediction markets for elections guide goes deeper on each.
What to watch through the summer
Three things will move prices through Q3 2026. The first is each party’s fundraising trajectory and the open-seat picture as primaries finish. The second is generic ballot polling and approval movement, both of which have historically tracked closely with midterm contract prices. The third is any unexpected national event that reshapes the news cycle, which prediction markets tend to absorb faster than polling can.
For the latest weighted rankings of every prediction market platform that lists US political contracts, see the 2026 PredictWire rankings.
About this article: Written and reviewed by The PredictWire Research Team under our Editorial Standards. Platform rankings follow our public Methodology. Prediction market contracts carry risk of total loss. Nothing here is financial advice. Corrections: corrections@predictwire.io.