TLDR Kalshi’s market favorite won 479 of the first 487 midterm races that were decided. Kalshi gave Democrats a 93% to 94.5% chance of winning the House on Election Day. Election contracts on Kalshi and Polymarket drew more than $3 billion in trading volume. Sen. Jeff Merkley and Rep. Maxine Waters are preparing legislative action aimed at prediction markets. Senators Elizabeth Warren and John Curtis questioned insider trading controls before the vote.
Prediction markets Kalshi and Polymarket picked the winners in almost every race of the 2026 US midterm elections. Now the party that won both chambers of Congress is preparing to take a closer look at how they operate.
Leading Democrats, including Sen. Jeff Merkley and Rep. Maxine Waters, have criticized the platforms for allowing bets on sensitive subjects. These include elections, war, and terrorism.
As of November 2026, both lawmakers are preparing legislative action aimed at prediction markets. Democrats won majorities in the House and the Senate, which gives them more control over investigations and new rules.
How the Markets Called the Midterms
On Election Day, Kalshi priced the odds of a Democratic House majority between 93% and 94.5%. It placed the odds of a Democratic Senate majority between 73.5% and 76%.
The favorite on Kalshi won 479 of 487 midterm races so far.
That’s 98%, forecasted before a single vote was counted.
The markets beat the polls and the models. The data pic.twitter.com/VMGrKCcWh2
— Kalshi (@Kalshi) November 4, 2026
Both outcomes happened. Democrats took control of the House and the Senate, as the market prices suggested.
The record was strong at the level of single races too. According to Kalshi data, the market favorite won 479 of the first 487 races that were decided.
That means favored candidates lost in