Prediction markets win big on election night - Semafor

Prediction markets emerged as big winners of the midterms. Kalshi and Polymarket correctly called the Democratic sweep of Congress by wider margins than most polling models, as well as key battleground races, though they missed surprises like Texas Gov. Greg Abbott’s loss and Democratic Senate victories in Iowa and South Carolina.

Trading volume on down-ballot elections grew nearly fivefold from the 2024 cycle to this year’s midterms to $1.8 billion, according to a Semafor analysis of the sites’ public data feeds. Sports and crypto bets still dwarf election contracts across both platforms, and the 2026 midterms attracted less trading interest than the presidential race.

Prediction markets have been racing to win over the sports-betting and gambling industries’ customers, executing aggressive ad campaigns to expand their influence. Kalshi has struck business partnerships with media outlets including CNN and Dow Jones, and its ad campaign on Meta rivals super PAC spending; Kalshi and Polymarket have also aired a slew of star-studded ads. But it’s one thing to bring in revenue, it’s another to do what the prediction markets say they do well: predict.