According to CNN, the bet was placed on the Betfair Exchange, the world’s largest online betting exchange, where gamblers find other gamblers who match their wagers.

CNN said the identity of the bettor, who placed the wager on October 29, is not known.

If Biden emerges, he would win a £540,000 ($696,170) profit on top of getting the original £1 million wager returned.

The £1 million wager is tied for the third-largest bet in Betfair’s history, behind £1.1 million bet on tennis player Rafael Nadal in the 2010 French Open, and slightly more than £1 million bet on Floyd Mayweather Jr. in his 2017 match against Conor McGregor.

One of the largest political bet ever made on Betfair Exchange was a £555,000 bet made on Trump in 2016.

Someone else placed a £550,000 bet on Hillary Clinton in 2016.

The turnout of the election is unprecedented. As of the time polling stations opened on November 3, 100 million Americans had cast their ballots, using early voting.

In 2017, there were 47 plus million early voters.