Prediction markets bet on Democratic sweep of House, Senate in midterm elections

Ahead of polls closing in the U.S. midterm elections, bettors on prediction market platforms are increasingly pricing in Democrats taking both the House and Senate.

As of early Tuesday afternoon, Polymarket users gave Democrats a 76% chance of securing the Senate, and the House a 94% chance. Similarly, on Kalshi, bettors said Democrats had a 94% chance of controlling the House and a 75% chance for the Senate. All 435 House seats are up for election, as well as 35 of the 100 Senate seats.

Prediction markets surged in popularity during the 2024 presidential election, emerging as an alternative barometer of public opinion and drawing comparisons to national polling. Since then, platforms like Polymarket and Kalshi have generated significant revenue and reached multibillion-dollar valuations.

But interest in election-related trading has cooled considerably since 2024, according to a Bloomberg report published Tuesday. Politics accounted for just 1% of trading volume on both Kalshi and Polymarket in October, down from more than 60% during the 2024 election, Bloomberg reported.

The shift 

A shift in parties is pivotal since Democrats are likely to then lead key committees, driving the agenda. For crypto, that could mean that Democrats such as Elizabeth Warren and Sherrod Brown could lead panels overseeing the digital asset industry.

Experts who spoke with The Block last month said that would mean more oversight over key issues, including President Donald Trump's crypto wealth through his family's World Liberty Financial, and less of an emphasis on crypto legislation.

As for key crypto races, such as Ohio, where incumbent Jon Husted will face off against crypto critic and former Sen. Brown, bettors on Kalshi say Brown has a 71% chance of beating Husted. For other races, including lawmakers focused on crypto legislation, Sen. Cory Booker, D.-N.J. has a 98% chance on Kalshi.