Polymarket and Kalshi predict the probability of the Democratic Party controlling both houses to be 78% and 74%

The prediction market platforms Polymarket and Kalshi are optimistic about the Democratic Party controlling both the House of Representatives and the Senate in the 2026 U.S. midterm elections. Polymarket gives a 78% probability, with related market trading volume exceeding $58 million; Kalshi gives a 74% probability, with related contract trading volume exceeding $100 million.

The individual Senate district markets on both platforms also favor Democratic candidates: James Talarico has a winning probability of 74% to 76% in Texas, Troy Jackson has 73% in Maine, and Abdul El-Sayed has 78% in Michigan. Traditional polls also indicate that the Democratic Party may experience a "blue wave."

Kalshi CEO Tarek Mansour stated that this election is the first prediction market election, with related betting transactions exceeding $1.4 billion. However, the platform previously failed to predict Brazilian President Luiz Inácio Lula da Silva's victory in the runoff, and its impact on voter behavior and electoral credibility is also under scrutiny.