Why Trump-backing betting market Polymarket might be a scam

A betting market heavily promoted by Donald Trump ’s supporters as evidence of his likely victory has been manipulated by multi-million-dollar bets, giving the impression that his win is inevitable, experts are suggesting.

Polymarket has gained significant attention for showing a high “percentage chance” of Trump winning, widely circulated on X (formerly Twitter) and other platforms. It has been used to portray what is presented as a closely contested race in most polls as highly likely to swing in Trump’s favour.

At the time of writing, Polymarket was claiming Trump had a 61.9% chance of defeating Vice President Kamala Harris .

Among those promoting Polymarket are Elon Musk , who has argued that the platform is more accurate than political polls and shared it with his followers on X, and Joe Kernen, co-host of CNBC’s Squawk Box and a conservative commentator, who has repeatedly referred to it on air and online.

The site is funded by Republican megadonor Peter Thiel , a close associate of Musk.

A staggering $30 million—sufficient to significantly increase Polymarket’s depiction of Trump’s chances—has been funnelled into the platform this autumn from four accounts. Experts believe these accounts may be controlled by the same individual, according to a report by The Wall Street Journal.

Polymarket operates by allowing users to bet anonymously on world events using cryptocurrency. Like traditional betting systems, the more money placed on a specific outcome, the higher the platform estimates the likelihood of that outcome. As a result, large sums wagered on a Trump victory have artificially inflated the site's projection of his chances.

The multi-million-dollar wagers, identified by The Wall Street Journal and placed by users Fredi9999, Theo4, PrincessCaro, and Michie, were all for a Trump win on Election Day or related scenarios, such as victories in Pennsylvania or the popular vote. The funds for these bets were reportedly deposited via Kraken, a US-based cryptocurrency exchange.

These bets have drastically skewed Polymarket’s election odds in Trump’s favour. A month ago, Harris had been given a 52.3% chance of winning, but by Friday morning, this had dropped to 38.2%.

Christopher Gerlacher, a political analyst from Prediction News who monitors market trends, commented to The Daily Beast that Polymarket’s sudden shift was very likely due to market manipulation . He noted that Fredi9999 had invested more than twice the amount in Trump compared to the next largest bettor.

Despite this, conservatives have embraced the Polymarket odds as supposed proof of Trump’s growing dominance, and that—just like in 2016—the pollsters are once again underestimating his popularity. However, Gerlacher emphasised that prediction markets and political polls are not the same, a distinction recently explained by Manifold Markets.

Simon Rosenberg, a Democratic strategist and blogger, has criticised the widespread sharing of these betting market odds by Republicans as “Polymarket voodoo,” considering them irrelevant for analysing the true state of the election.

Rosenberg suggested that wealthy individuals from countries such as Russia, China, Iran, and North Korea could be manipulating Polymarket, adding that it was unreasonable to take such market activity seriously in the context of a US election.

Musk has been a prominent supporter of this so-called voodoo. He was one of the first high-profile Republicans to acknowledge Polymarket’s odds shift in Trump’s favour and promote it further. In early October, he shared a post on X, suggesting that Trump was leading Kamala Harris by 3% in betting markets and stating that this was more accurate than polls because real money was at stake.

The following day, Musk engaged with a post featuring a screenshot of a Polymarket graph showing Trump’s rising victory odds, commenting that Trump’s win needed to be decisive.

Others, like Kernen, have also promoted Polymarket as a legitimate measure of the presidential race, with Kernen sharing a screenshot of Trump’s Polymarket lead to criticise Democratic commentator Fred Wellman for suggesting Trump’s campaign was struggling.

There are concerns that the $30 million in wagers could be a form of market manipulation, and that Trump, should he lose in November, might use Polymarket’s odds as evidence the election was stolen from him.

The identities and motives behind these wagers remain unclear. Political gamblers have reportedly attempted to contact the mystery millionaire or billionaire behind the accounts but have yet to uncover any definitive answers. According to The Wall Street Journal, the oldest of these accounts was created in June, while the most recent was set up this month.

Rutgers University statistics professor Harry Crane suggested that the bettor may not have had any malicious intent, noting they may simply possess the resources and confidence in Trump’s success.

Crane indicated that purchasing a large number of shares for a single outcome does not necessarily imply a hidden agenda or an attempt to manipulate the market.

Nonetheless, other betting markets, such as Britain’s Betfair and New Zealand’s PredictIt, also show Trump as the favourite to win, although not to the same extent as Polymarket.

However, The Wall Street Journal has reported that Polymarket is investigating activity in its presidential election markets, with assistance from external experts. As political betting markets have grown significantly since 2012, such investigations may become more common.

Rajiv Sethi, a professor at Barnard College, who once studied market flooding tactics to boost a candidate, suggested that Polymarket’s mystery gambler could be attempting to provide Trump with a final momentum surge. Sethi remarked that, if one were to manipulate a market, this would be the exact method to do it.