Bettors from offshore platforms believe that Vice President Kamala Harris has either closed the gap or taken the lead in the 2024 presidential race after her first debate with former President Donald Trump on Tuesday night.

In the first 50 minutes of the debate, $750,000 was wagered, leading to a shift in betting odds from Trump to Harris on the Betfair Exchange, which is the largest peer-to-peer betting platform in the UK. It’s worth noting that betting on presidential elections is illegal in the U.S.

On the crypto-trading site Polymarket, the odds of Trump and Harris winning were even at the debate’s conclusion. Though they initially favored Trump slightly on Wednesday, by Friday morning, Polymarket bettors indicated Harris had a slight edge.

How Harris’ chances increased during the debate

It wasn’t just bettors who felt Harris gained an advantage during the debate. A quick poll conducted by CNN found that nearly two-thirds of viewers believed Harris had won, supporting trends seen in previous presidential debates.

Historically, first debates play a crucial role in influencing polling and betting odds, as shown in the past four election cycles, per data from Betfair and Real Clear Politics. Public perception of the debate outcomes tends to accumulate in the days following the event.

The shift in Trump and Biden’s odds and polling after the June debate

This pattern was evident during Trump’s debate with President Joe Biden in late June. Trump’s odds and polling improved after Biden’s subpar debate performance, which ultimately resulted in Biden withdrawing from the race.

Despite the unconventional summer debate between Trump and Biden, the betting trends mirrored those observed in Trump’s previous campaigns. After their first debates, both Biden and Hillary Clinton saw increases in their leads over Trump. However, the outcomes in November were quite different, and it’s too early to assess how the results of Tuesday’s debate may affect either candidate.

Changes in odds and polling after Trump’s previous first debates

Trends in Trump winning the 2024 presidency odds

Trump’s odds of winning the presidency peaked on the first day of the Republican National Convention, according to data from Betfair and Polymarket. In the past week, bettors had given him an advantage over Harris.

The betting odds for the 2024 election are expected to fluctuate as Election Day on November 5 approaches, especially since Betfair has already recorded $82.7 million in bets. This amount is just a fraction of the record $2.23 billion wagered during the 2020 election.

Changes in Harris’ and Trump’s 2024 election odds

Historical accuracy of election betting odds

Since 1866, the betting favorite has only lost twice, according to the non-profit news organization, the Conversation. One instance was Trump’s campaign in 2016, where he was given only a 17% chance of winning against Hillary Clinton even on Election Day, based on Betfair’s past data.

Contributors: James Powel