With 23 days until Election Day on November 3, 2026, prediction markets have moved decisively on several key races. As of October 11, Kalshi and Polymarket traders are now pricing Republicans as a modest favorite to hold the Senate at 62%, while House control has tightened to a near coin flip. Below is PredictWire’s weekly tracker of the markets that matter.
Senate Control: Republicans Favored, but the Map Is Narrowing
The headline Senate control contract on Kalshi has drifted from 71% Republican two weeks ago to 62% today, driven almost entirely by movement in three toss-up states. Polymarket’s parallel market sits at 61%, well within arbitrage range of Kalshi after fees.
The seats moving the market this week:
- Ohio: Republican hold odds dropped from 78% to 64% following a tighter-than-expected debate on Thursday. Volume on this contract has tripled in the last seven days.
- North Carolina: Still the pivotal seat, now trading at 54% Republican. Early-vote data releases on October 20 are expected to drive significant volume.
- Pennsylvania: Democratic incumbent now favored at 58%, up from 51% last week after a strong fundraising quarter was disclosed.
- Montana: Republican lock at 89%. Market effectively closed on this one.
Traders should note that Senate control markets historically overreact to single polls in the final month. The Kalshi order book shows thin liquidity above 65%, suggesting room for Republican odds to spike on any favorable late break.
House of Representatives: The Toss-Up of the Cycle
House control is where prediction markets are earning their reputation this cycle. The Kalshi “GOP retains House” contract now trades at 51%, essentially a coin flip, with Polymarket within one point at 50%.
Three dynamics are driving the volatility:
- Redistricting rulings in two states have shifted an estimated four seats in the generic ballot since September.
- Retirement announcements have cleared the field in six previously safe districts, creating open-seat uncertainty that markets dislike.
- The generic congressional ballot on prediction markets now favors Democrats by 1.8 points, down from 3.2 points in late August.
Expect House control markets to swing 10 to 15 points in either direction on election night as individual races call. Traders positioning for volatility should watch Kalshi’s hourly contracts, which open 24 hours before polls close.
Governor Races: Three Markets Worth Watching
The 2026 cycle features 36 governor races, but prediction market volume is concentrated in a handful:
- Georgia: Republican hold at 56%. Down from 68% in September.
- Michigan: Democrat hold at 72%. Market has barely moved in six weeks.
- Arizona: Toss-up at 51% Republican. The highest-volume governor contract on Kalshi this week, with over $4.2 million in notional traded in the last seven days.
- Nevada: Democrat favored at 59%, with the incumbent benefiting from strong early-vote enthusiasm indicators.
- Wisconsin: Toss-up at 48% Democratic hold. Expect this one to swing meaningfully on any debate performance.
Governor races tend to be less correlated with national winds than Senate or House seats, which makes them a useful diversifier for traders who are already positioned on top-line control markets.
Presidential 2028 Markets: Early Movement
While attention is on November, 2028 presidential nomination markets have already begun to price in midterm outcomes. On Polymarket:
- Republican nominee market is led by three candidates clustered between 18% and 24%.
- Democratic nominee market is more diffuse, with the top candidate at only 15%.
- The “Democrat wins 2028 presidency” contract now trades at 51%, up from 44% in August.
These contracts have more than two years to run, so volume remains modest, but they are a leading indicator of how traders expect the midterms to reshape the national landscape.
Where to Trade
Both Kalshi and Polymarket offer deep liquidity across the 2026 election slate. Kalshi carries the full catalog of US political contracts under its CFTC-regulated framework, while Polymarket, operating offshore for US users, often offers thinner spreads on specific candidate markets and all 2028 contracts.
For a complete breakdown of the top-rated platforms, see our best prediction markets rankings.
Odds and percentages reflect market consensus as of October 11, 2026, 11:00 UTC. Markets move constantly; always verify current pricing before trading.