US midterms: Prediction markets give Democrats 71% chance of Senate control, 95% for House
&imwidth=600&imheight=450&format=webp&quality=medium "US midterms: Prediction markets give Democrats 71% chance of Senate control, 95% for House")
US President Donald Trump arrives for a Halloween party at his Mar-a-Lago residence in Palm Beach, Florida on October 31, 2026. Photograph: (AFP)
Kalshi and Polymarket give Democrats a 71–72% chance of winning the US Senate and up to 95% odds of taking the House in the 2026 midterms.
Prediction markets are favouring Democrats to win the Senate. Kalshi prices Democrats at 71cents, about a 71% chance, and Republicans at 30 cents, about 29%. Polymarket has Democrats at 72% and Republicans at 28%. On the House, Polymarket trading gives Democrats 95% and Republicans 6%, while Kalshi traders are giving Democrats 93.3% and Republicans a slim 6.7% chance.
On Polymarket, total trade volume on the Senate race is over $13.96 million and on Kalshi $197.56 million, the cumulative trade volume on Senate is $211.53 million. On Kalshi, total trade volume on the House is $ 198.041 million, and on Polymarket it's $35.8 million.
Polymarket's balance-of-power market puts a Democratic sweep of both chambers at 71%, a Republican Senate with a Democratic House at 24%, and a Republican sweep at 5%. Its map projects 52 Democratic seats and 47 Republican seats, with 51 needed for control. The Democratic lead has grown through October. Kalshi first moved Democrats ahead on September 14, at 53%. By October 25, it was at 65%, and Polymarket was at about 67% on October 24.
Key Races
The two markets agree closely on every key race, within two points. Democrats are favoured in Texas, Michigan, Maine and Ohio. Republicans are favoured in Iowa and South Carolina. Kansas is a toss-up. Kansas moved the most, with the Democratic price up 14 points. Texas is up 8, Ohio up 7, Michigan up 6.5 and Maine up 5. Hinson in Iowa is down 2.5, Graham in South Carolina is down 6.5, and Peltola in Alaska is down 3.
Texas is the biggest race at $68.6mn, up from $10.7mn in early September. Ohio is at $9.9mn, up from $2.6mn. The other key races have only a current figure: Michigan $19.5mn, Maine $17.9mn, Iowa $8.5mn, South Carolina $ 8.5mn, and Kansas $8.1mn.
On Polymarket, Senate control volume is $14M, up from $4.45M in mid-September. The House market has $35M, and the balance of power market has $48M. Its race volumes are for the last 7 days only: Texas $9M, Michigan $6M, Maine $3M, and $2M each in Alaska, Ohio, Nebraska, Kansas and South Carolina, with Iowa at $1M.
