Opinion polls have Harris and Trump locked in a tight race. ‘Gambling polls’ say otherwise

Most gamblers might want to sit out the US election. It’s too close to call with Kamala Harris and Donald Trump neck and neck, according to official polls. But the former president’s campaign has latched on to signs he says prove he’s actually “leading”.

In a close race, Trump and his allies claim some “gambling polls”, as he described them last week, put him significantly ahead of Harris. “Like, 65 to 35, or something like that.”

The irony of touting an apparent lead in betting markets at a Believers and Ballots campaign event in Georgia aimed at Christian voters was not lost on Trump. “But nobody here gambles,” he continued. “Does anybody here gamble? No, no, no, no. Great Christians don’t gamble, do they? Oh no.”

The “gambling polls” Trump cited are forecasts generated by several election betting platforms, which put his chances of regaining the White House markedly ahead of his Democratic rival’s. With many questioning the accuracy of political polling, supporters including Elon Musk, have started to claim such estimates are more accurate.

As of Wednesday, Polymarket, one leading service, put Trump’s chances of winning back the presidency at about 67%, with Harris at 33%. Another, Kalshi, put Trump at 62% and Harris at 38%.

And while Trump’s audience last Tuesday was not interested in gambling on the result of the presidential election, many others appear to be getting involved. High-profile legal battles, promotion by the likes of Musk and Trump, and growing media coverage, have helped propel the activity into the spotlight as the campaign gathered steam.

Interest around betting on this election is “orders of magnitude larger” than previous ballots, according to Thomas Gruca, a professor of marketing at the University of Iowa, and director of Iowa Electronic Markets, an election-focused futures market first established in 1988.

America’s gambling boom, led by the legalization of sports betting, “has increased the number of people who like to throw away their money on things they don’t understand”, said Gruca. “People think, ‘I picked the Raiders-Jets game, therefore, I can pick a president.’”

He also pointed to opinion polling errors at previous elections, and how many polls this time around suggest the contest is extremely tight. “I haven’t looked at the polls in the last 15 minutes, so I don’t know who’s winning. In previous years there was a lot of clarity.”

In the magazines and newspapers section of Apple’s iPhone store, Polymarket has reigned supreme in the top spot, leaving the New York Times, Wall Street Journal and, yes, the Guardian, in its wake. Another platform, Kalshi, has likewise surged up the store’s chart of financial apps.

“I don’t think it’s a coincidence that these markets have been becoming more popular as trust in the media has been declining,” said Harry Crane, a professor of statistics at Rutgers University. “The public wants information and is looking for sources of information it can trust.”

Should you have turned to, say, Polymarket, on Wednesday and bet on Trump, you would receive $1 for every 67 cents you wagered if he wins the election. If you bet on Harris, on the same platform, on the same day, you would receive $1 for every 33 cents wagered if she wins.

These bets are bids on political futures contracts. Buying a contract drives its price – or the perceived probability of it happening – higher.

This ecosystem spans far beyond the race for the White House. Other markets on Kalshi include the margin of victory in the Senate, which state will have the closest presidential election result and what the Federal Reserve will do with interest rates two days after the election.

But how reliable are the headline figures? “I think you should take them seriously,” said Grant Ferguson, political scientist at Texas Christian University. “The people who bet on these markets largely think they know more than the average person as to how things are going.”

Leading platforms put Hillary Clinton ahead on election day in 2016 (she did win the popular vote if not the presidency), and Joe Biden in the lead in 2020, “but by less than the polling, in both cases”, said Ferguson. 2024 will be the biggest test of these predictions so far.

“Broadly these markets are actually quite efficient – particularly they’re quite good at things that are 50:50, 60:40,” said Eric Zitzewitz, professor of economics at Dartmouth College. “In the sort of circumstance we’re in right now … I take that pretty seriously.”

Provided a market is run “efficiently, or with good rules, the prices before the event happens will reflect what the smart people think, and not just random people”, suggested Gruca.

The Iowa Electronic Markets allows participants to bet up to $500 on a given contract, and PredictIt, run out of Victoria University in Wellington, New Zealand, has a $850 limit. But other platforms do not have such tight restrictions, and big bets may have moved the odds in Trump’s favor.

Polymarket, which did not respond to requests for an interview, confirmed last week that one person – a French national – was behind four accounts which had placed bets on Trump worth around $28m, but insisted to the New York Times this was “based on personal views”, rather than an attempt to manipulate the market.

“Without limits,” said Gruca, “you can have prices move away from what they should be.”

If one person tries to tilt the odds toward their favored candidate, those betting would quickly back the other if their odds slipped too low, Ferguson suggested. “Does it probably happen? Yeah,” he said. “But I’m not real worried about it.”

There is a small, but significant, difference in the question at the heart of election surveys, and election bets. While poll respondents are indicating which candidate they want to win, those gambling on the contest are saying who they think will. Veterans of the space like to say that polling participants focus on their heart, and bettors use their head.

The betting markets “are asking the more relevant question”, argued Crane. “The polling information is in the markets. The people who are in the markets know what the polls are, but they have other information.”

Regulators are not happy. The Commodity Futures Trading Commission, which fined Polymarket $1.4m in 2022 and ordered it to exclude US users as part of a settlement, has tried to shut down PredictIt and Kalshi.

But Kalshi was recently cleared to take US bets on election outcomes, when a federal appeals court ruled that the CFTC had failed to show how the agency or public interest would be harmed by its event contracts.

While the CFTC is appealing, the legal breakthrough appears to have set the stage for a further increase in bets placed on who will prevail in the presidential campaign – by both individual betters, and large institutions. Polymarket is also scrutinizing activity on its platform to ensure users are outside the US, amid reports of domestic usage.

“The markets are only as smart as the people trading in them,” said Gruca. “If you are dumb as a rock and have a lot of money, you can move the markets in whatever direction you want by simply moving money.”