Analysis
Election Day: Bettors Price a 74% Democratic Sweep
Prediction markets gave Democrats a 74% chance of winning both chambers of Congress in Tuesday's midterms, Polymarket showed on Monday. Kalshi put a Democratic House at 94%.
Americans vote on Tuesday, November 3, and the markets that trade on the result have rarely been this one-sided on the eve of a midterm. On Monday Polymarket gave Democrats a 74% chance of winning both the House and the Senate, according to the Boston Globe; a Democratic House with a Republican Senate stood at 23%, a Republican sweep at 6% and a Republican House with a Democratic Senate at 2%. Kalshi showed the House at 94% "Safe Dem" and the Senate at 74% "Leaning Dem" in early afternoon trading.
The Senate is where the uncertainty sits, and both platforms agree on the races that decide it. In Maine, Democrat Troy Jackson was priced at 73% on Polymarket and 72% on Kalshi to unseat Susan Collins; in Michigan, Abdul El-Sayed at 78% against Mike Rogers; in Texas, James Talarico at 74% to 75% against Ken Paxton; and in Ohio, Sherrod Brown at 71% to win back a seat against Jon Husted. None of those numbers is a certainty: a 70% favourite loses three times in ten, and a sweep requires most of them to land together.
Stocks spent the eve of the vote on something else. The Dow rose 0.41% to 51,983.98 on Monday while the S&P 500 fell 0.51% to 7,541.40 and the Nasdaq 1.07%, a split driven by another sell-off in AI and chip stocks, not by politics. The VIX still rose 9.58% to 21.28, a level that includes some election hedging. The war with Iran entered the picture too: President Trump has said he will not strike Iran before the vote, and oil had its biggest drop since July on Monday as he spoke of giving diplomacy more time.
What matters for markets is the gap between the result and these prices. A Democratic House, at 94%, is already in the price, and with it two years of gridlock for any new legislation from the White House. The surprises would be a Republican House, at about 8% across the two Polymarket outcomes, or a Senate that stays Republican, at about 29%. A divided Congress has historically been a neutral-to-positive backdrop for stocks, mainly because it limits fiscal surprises in both directions.
The first polls close at 6 p.m. Eastern time in parts of Indiana and Kentucky, and US index futures trade through the night, so the first reaction will come in the futures market and in Asia rather than at Wednesday's open. Close Senate races can take days to call. And the next scheduled test arrives quickly: the October jobs report on Friday, November 6, which will matter more for the Fed than any seat count.