New York: Online trading platform PredictIt and bookermaker Paddy Power showed a massive reversal of fortune for the US presidential candidates Republican Donald Trump and Democrat Hillary Clinton Tuesday night, with the New York businessman’s chances of taking the White House skyrocketing on both.

Trump stunned many political experts, showing a slight edge on Clinton in several swing states after voting had ended in more than two-thirds of the 50 US states.

Paddy Power put Trump’s chance of victory at 83.3 per cent Tuesday and Clinton’s at 22.2 per cent. The two had been in essentially opposite positions on Tuesday morning.

The Irish bookmaker stands to take a $4 million hit if Trump wins, said Paddy Power spokesman Féilim Mac An Iomaire, who said the dramatic reversal in odds was reminiscent of what it saw in the ‘Brexit’ vote for Britain to leave the European Union.

‘You could say it’s deja vu again,’ said Mac An Iomaire. ‘Much like Brexit, it looked to be following the odds early on before a dramatic turnaround.’

While opinion polls went back and forth leading into Britain’s June 23 referendum on whether or not to remain in the EU, betting odds favoured the ‘remain’ campaign. Britons voted to leave by 52 per cent to 48 per cent.

A similar trajectory played out on the online trading platform PredictIt, which was launched in 2014 and is jointly run by Victoria University in Wellington, New Zealand, and Washington-based political consulting firm Aristotle International Inc.

Clinton led Trump in PredictIt’s market on who will win the White House throughout the campaign, but news of her Republican challenger’s surprise momentum sent her chance of winning the election plummeting more than 50 percentage points from its level Tuesday morning to 25 per cent.

Trump’s chance, meanwhile, shot up more than 40 percentage points to around 65 per cent.

It was the first time in the entire campaign that Trump had led Clinton on the platform, according to a PredictIt spokeswoman.