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Prediction markets are now leaning more clearly toward a Democratic Senate flip in 2026, with Kalshi pricing that outcome at 63% and Polymarket at 66% as of Wednesday. The move follows a Cook Political Report update that shifted Senate races in Georgia, Kansas and South Carolina toward Democrats, underscoring a more competitive map than Republicans might have expected with a current 53-47 majority.
Prediction markets turned notably in one month
The market move is notable because it reverses where traders were just a month earlier. Newsweek reported that Republicans then held a 53% edge on Kalshi, while Polymarket was effectively even.
For readers who track election contracts, that means sentiment has shifted alongside traditional handicapping. Cook’s latest adjustments did not settle the race for control of the chamber, but they added to the view that Democrats have a plausible path back to a majority.
Three races moved toward Democrats
Cook shifted Georgia, Kansas and South Carolina in Democrats’ direction.
Georgia remains one of the clearest battlegrounds. The state backed Donald Trump over Kamala Harris by about 2 points in 2024, but recent polling cited by Newsweek showed Sen. Jon Ossoff ahead of Republican Mike Collins. A YouGov poll had Ossoff up 51% to 41%, a Quantus Insights poll showed a 49% to 45% lead, and an AARP poll put him ahead 52% to 43%.
Kansas and South Carolina are more surprising additions to the competitive conversation because both were solidly Republican at the presidential level in 2024. Trump carried Kansas by 16 points and South Carolina by 18 points, according to the report. Still, an Emerson College poll found Democrat Adam Hamilton leading Sen. Roger Marshall 45% to 43% in Kansas, while two South Carolina polls showed a tight race between Republican Darline Graham and Democrat Annie Andrews.
What to watch next in the Senate market
Cook said the broader fight for control could come down to seven toss-up races: Alaska, Iowa, Maine, Michigan, New Hampshire, Ohio and Texas. That leaves traders and election watchers with a wider map than just the three states that were newly shifted.
The next fixed date is Election Day on November 3, 2026. Until then, polling updates, rating changes and market repricing on platforms such as Kalshi and Polymarket are likely to remain key signals in the Senate-control market.
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Source: As reported by Andrew Stanton.
