Betting markets have picked a winner in the US midterms. Here’s how often they get it right

As the election battle draws closer, curiosity about the winners is gaining momentum among voters. Who will emerge victorious in this battle, as the donkeys and elephants fight for control of the House and the Senate? Which way is the American sentiment leaning in the 2026 midterm elections?

The betting markets are favoring Democrats to win control of both the Senate and the House of Representatives ahead of the November 3 US midterm elections.

Kalshi shows Democrats a 72% chance of winning Senate control and a 94% chance of taking the House. Similarly, PredictIt's betting-market prices on November 2, 2026, put Democrats ahead in both chambers of Congress, with a 92% chance of winning the House and a 72% chance of winning the Senate.

But how often have betting markets predicted elections correctly?

In 2022: Betting markets favored Republicans with a 67% chance of winning the Senate race. They also strongly favored Republicans to take the House. The betting markets were right about Republicans winning the House of Representatives; however, they got the bigger Senate picture wrong, as Democrats retained control.

2018: Political betting markets favored Democrats to win the House and Republicans to retain the Senate. Both predictions came out correct.

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2010: Betting markets leaned towards Republicans to win the House and Democrats to take control of the Senate. The election results matched both predictions.

2006: Betting markets picked Democrats to win the House and Republicans to retain the Senate. While Democrats won the House as expected, they also took control of the Senate, contrary to market expectations.

Political betting has grown significantly since 2016 into a billion-dollar business today.

During the 2020 US presidential elections, approximately $1 billion was traded in political betting. In that election, Betfair accounted for over $630 million alone. PredictIt's growth in the number of users and traders also suggests the popularity of betting during elections. In the 2016 US Presidential elections, PredictIt had 22,000 traders, followed by 177,000 in November 2022, to reporting 400,000 users in 2025.

According to a CNN report published on October 23, trading volume across prediction markets had crossed $1.4 billion ahead of the 2026 midterms.

It has been noted that the betting markets react to political developments much faster than conventional opinion polls. The trading costs change almost immediately after any major political event.

Let's take the 2022 US Senate election in Pennsylvania, for example, where Republican Mehmet Oz faced Democrat John Fetterman in a debate. Before the debate, a contract betting on Oz's victory was trading at 53 cents. Following the debate, more traders began betting on Oz to win, pushing the contract price as high as 66 cents.

In other words, traders became more confident of an Oz victory after the debate. However, Fetterman ultimately won the election.

A 2026 study by Joshua Clinton and TzuFeng Huang analysed close to 2,200 political betting markets across PredictIt, Kalshi, Polymarket and Iowa Electronic Markets. The research found that when contracts in the 2024 US presidential election were priced between 40 and 60 cents, the market favorite won only 55% of the time. These findings hint that political betting markets can give useful predictions about electoral outcomes, but trader favorites do not always get a guaranteed win.

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But how does this political trading work?

For example, when a trader buys a contract for 60 cents, they would receive $1 if the predicted candidate or party wins.

So, what does it mean?

That means a profit of 40 cents on each winning contract, before fees.

If the prediction ends up being wrong, the trader loses the entire amount he has invested. But as more traders bet on a particular result, the contract price can rise, which reflects growing confidence in that result.

Regulatory challenges

Despite their growing popularity, political betting platforms have faced regulatory challenges in the United States.

In 2022, the US Commodity Futures Trading Commission (CFTC) ordered PredictIt to wind down its operations. The regulator also fined Polymarket $1.2 million over its event-based betting contracts. The regulatory landscape has since changed, even as political betting continues to attract traders ahead of major US elections. It is yet to be seen who wins the battle for the House and the Senate in these midterm elections, while the bettors side with Democrats this year.