Voters Face $1.9B in Election Bets as Democrats Hold Strong Odds

Election Day for the 2026 midterms is here, and private markets have already priced in a likely Democratic victory.

According to a Washington Post analysis, nearly $1.9 billion was wagered on the two largest prediction platforms by 8 p.m. ET on Monday. Kalshi accounted for approximately $1.3 billion of that total, while Polymarket handled the remaining $600 million. These platforms allow users to buy and sell contracts on specific political outcomes, creating a real-time market for election results.

Current trading data favors the Democrats on both chambers. Polymarket lists the party's probability of winning the Senate at 78% and flipping the House at 95%. Kalshi offers similar odds, placing the Senate chance at 78% and the House probability at 93.9%. This market consensus stands in contrast to the 2024 presidential cycle, where prediction markets correctly identified Donald Trump as the winner despite polls suggesting a double-digit lead for Kamala Harris.

The platforms have implemented rules to ensure fair trading. Kalshi defines insider trading as trading while possessing information that materially affects the decision to trade. The company states it bans such activity. Polymarket also prohibits insider trading and reported to NPR that it has investigated dozens of trades related to these midterms for potential manipulation.

The volume of money in these markets is substantial but remains lower than the total advertising spend for the races. A New York Times analysis of AdImpact data indicates that candidates will spend about $3.9 billion on ads across House and Senate races. This ad spend is roughly double the current total wagered on prediction markets. However, the betting volume for these midterms is less than half of the $3.6 billion wagered on Polymarket alone during the 2024 presidential election.

The 2026 midterms will determine control of the U.S. Congress. Traders on these platforms are betting on the specific composition of that government. The markets currently reflect a high degree of confidence in a Democratic takeover of both the House and the Senate.