With 56 days until the November 3 midterms, prediction markets have moved sharply this week. Democrats are now the favorite to win Senate control at 58 cents on Kalshi (up from 52 last Monday), while Republicans hold the House at 61 cents. Governor races have shifted less than expected, but three key state contests moved more than 5 points on volume of over $2 million in the past seven days. This is the September 8 snapshot of where the money is on Kalshi and Polymarket.
Senate Control: Democrats Pull Ahead on Ohio and Pennsylvania Movement
The most consequential move of the week was in Ohio, where the Democratic incumbent’s odds climbed from 44 to 53 percent after a strong second-quarter fundraising report and a widely covered debate. Pennsylvania moved in parallel, with Democrats now favored at 56 percent to hold the seat. Combined, those two contracts drove the overall Senate control market up 6 points.
Current Kalshi pricing on Senate control: Democrats 58 percent, Republicans 42 percent. Polymarket has Democrats slightly higher at 60 percent, suggesting a modest 2-cent arbitrage window that has persisted for three days.
The states carrying the most weight in these markets right now:
- Ohio: Democrat 53 percent (up 9 points week over week)
- Pennsylvania: Democrat 56 percent (up 4 points)
- North Carolina: Republican 54 percent (unchanged)
- Georgia: Democrat 51 percent (up 2 points)
- Montana: Republican 67 percent (down 3 points)
- Nevada: Democrat 62 percent (up 1 point)
House Control: Republicans Still Favored, but the Margin Is Tightening
The House control market on Kalshi sits at Republicans 61 percent, Democrats 39 percent. That is down from a Republican peak of 68 percent in mid-August. The tightening reflects Democratic overperformance in three recent special elections and stronger-than-expected polling in California and New York competitive districts.
Traders are focused on roughly 22 truly competitive races. The consensus battleground pricing shows Democrats favored in 11, Republicans favored in 8, and 3 essentially coin flips. To flip the House, Democrats need to net five seats. Current market-implied probability of that specific outcome: 39 percent.
The most heavily traded individual House contracts this week:
| District | Democrat Odds | Weekly Move | Volume (7d) |
|---|---|---|---|
| CA-27 | 54% | +3 | $412,000 |
| NY-17 | 58% | +5 | $387,000 |
| PA-08 | 47% | -2 | $298,000 |
| MI-07 | 51% | +4 | $266,000 |
| VA-02 | 49% | +1 | $241,000 |
| IA-03 | 43% | -3 | $219,000 |
Governor Races: Three Big Moves This Week
Governor markets are usually quieter than Senate or House contracts, but three races broke that pattern in the past seven days.
Arizona: The Democratic candidate jumped from 48 to 56 percent after a widely covered debate performance and a favorable state supreme court ruling on ballot access. This was the largest weekly move in any 2026 governor contract.
Georgia: The Republican dropped from 62 to 55 percent as new polling showed the race tightening in the Atlanta suburbs. Volume surged past $1.1 million on Polymarket alone.
Nevada: The incumbent Democrat’s re-election odds slid from 71 to 63 percent following a series of local news stories about state budget shortfalls. Republicans are now pricing in a legitimate upset opportunity.
Other notable governor contracts: Ohio Republican 68 percent (steady), Michigan Democrat 61 percent (up 1), Wisconsin Democrat 54 percent (down 2), New Mexico Democrat 71 percent (unchanged), Iowa Republican 66 percent (unchanged).
Who Controls Washington in 2027? The Combined Market
Kalshi runs a combined contract on the specific configuration of Washington after the midterms. Current pricing:
- Split Congress (Dem Senate, GOP House): 41 percent
- Full Republican control of Congress: 24 percent
- Full Democratic control of Congress: 17 percent
- Split Congress (GOP Senate, Dem House): 18 percent
The split-Congress outcome with Democrats holding the Senate is now the modal expectation. That is a meaningful shift from June, when full Republican control was the plurality outcome at 38 percent.
What Traders Are Watching Next
Three catalysts on the near-term horizon are likely to move markets meaningfully.
September jobs report (October 3): A soft print historically hurts the incumbent party. Markets are pricing a 46 percent chance of a payrolls miss.
Presidential approval trend: Contracts on the September 30 Gallup approval reading show a 54 percent chance of a print between 42 and 46 percent, a range that historically correlates with modest midterm losses.
Debate schedule: Seven of the ten most competitive Senate races have scheduled debates between September 20 and October 15. Debate contracts have been among the highest-return event trades in 2026.
Where to Trade
For US-based traders, Kalshi offers the deepest liquidity on election contracts and is the primary regulated venue for federal race markets. Polymarket often prices slightly differently on the same events, creating small but consistent arbitrage windows for traders with accounts on both platforms.
For an updated comparison of platforms, fees, and available election contracts, see our 2026 prediction market rankings.
PredictWire updates its election odds tracker weekly. Bookmark this page or check back every Monday for the latest movement across Senate, House, and governor contracts.