Kalshi stated that the trading volume of the midterm election-related markets exceeded 2.5 billion USD

The prediction market platform Kalshi officially disclosed that the total trading volume related to the 2026 U.S. midterm elections exceeded $2.5 billion, nearly double the $1.3 billion for the entire 2024 election cycle. On the day before and after the election, Kalshi's total nominal trading volume reached $4.15 billion (including non-election contracts). Paradigm co-founder Matt Huang revealed that on November 3, the trading volume for Kalshi's election contracts was $729 million, higher than the $244 million on the day of the 2024 U.S. presidential election. The single market for "Who Will Control the U.S. House of Representatives" had a cumulative trading volume exceeding $400 million.

Before the election, institutions such as The Washington Post reported that the combined trading volume of Kalshi and Polymarket was close to $1.9 billion, with Kalshi accounting for about $1.3 billion and Polymarket about $600 million. Polymarket's onshore and offshore combined trading volume was approximately $600 million to $700 million. Kalshi stated that among the 487 races where results were announced before 6:26 AM EST on November 4, the most popular candidates won 479 races, with an accuracy rate of about 98%. Their research team noted that the overall race accuracy rate increased from 93.8% three months ago to 98.2% by the end of voting.

Polymarket disclosed that the most popular candidates the day before the election won 419 out of 426 settled races, with an accuracy rate of 98.4%, and there were 78 races pending settlement; the accuracy rates for settled Senate, gubernatorial, and House races were approximately 97%, 97.1%, and 98.6%, respectively. Both platforms set the probability of the Democratic Party winning the House at about 94% and the Senate at about 75% before the votes were counted, and the final outcomes for both chambers were consistent with the results. Third parties pointed out that the market implied about 192 Republican House seats at the time of counting, which NBC later estimated to be 176 seats. Kalshi stated that the key Senate race pushed the winning side to over 99% on average about 115 minutes earlier than CNN's official announcement.