Kalshi’s and Polymarket’s CEOs are fierce rivals : NPR

Shayne Coplan (left) of Polymarket and Tarek Mansour of Kalshi are two twenty-something billionaires who run the largest prediction market sites. They have a long-standing rivalry.
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There is one word that Tarek Mansour, CEO of Kalshi, hesitates to say: Polymarket.

Like a politician who tramples his challenger who is never talked about during the election campaign, Mansour will train the enemy but never name him.

Yes, there is an “unregulated offshore prediction market”, which is not like Kalshi. According to Mansour, too many people confuse Kalshi with this “un-American and unregulated platform.”

For Mansour, distinguishing Kalshi from this other site is a form of combat. If there is a chance to land a blow, he will do it.

After the FBI raided the home of Polymarket CEO Shayne Coplan in November 2024, Kalshi employees teamed up with influencers to promote memes mocking Coplan, Mansour admitted the following month. “Some of our team were pretty heated,” he said at the time.

Mansour, in a podcast interview in December, compared his conflict with Coplan to one of the most exciting rivalries in NFL history, the showdown between Tom Brady and Eli Manning for football quarterback supremacy.

“When Tom Brady thought about it back then, he said, ‘You know, we were like the fiercest ones on the field, and we fought,'” Mansour said, adding that the rivalry ultimately led Brady to greatness.

Coplan has been more cautious in public regarding his foe in the prediction market, even if he quietly attacks those around him about Mansour, who continues to accentuate his antagonism.

Even the usually lumbering U.S. Patent and Trademark Office is seeing some of the action. Both Kalshi and Polymarket have pending trademark applications for “the world’s largest prediction marketplace,” according to federal records. (Kalshi is the largest in terms of trading volume, but Polymarket has long considered itself the largest.)

The feud could shape the future of the industry, with each executive offering competing visions for how prediction markets should develop, either by fighting in court for the legal right to exist or — like the cryptocurrency industry before them — trying to skirt U.S. regulations for as long as possible.

“Kalshi hates being lumped in with Polymarket,” said Dustin Gouker, who writes a forecasting markets newsletter and is also a consultant. “They’re trying to draw a line in the sand saying they’re this prediction market regulated by the CFTC and Polymarket is not,” he said, referring to the Commodity Futures Trading Commission. “I’m not sure that message is getting across, but it does reinforce the animosity between the two companies.”

A former Kalshi employee with direct knowledge of Mansour, who spoke to NPR on condition of anonymity for fear of retaliation, said the culture at the company is “uncompromising,” with Mansour relentlessly pushing his staff to meet his goals for new users and other metrics. The person said Polymarket’s popularity only exacerbated Mansour’s intensity.

“Tarek is so aggressive because the size of the bag is generational if they do it right,” the person said. “For them, it’s existential.”

The two fintech leaders being at loggerheads comes against a backdrop of boom in the prediction market sector.

The sites have grown exponentially in recent months, logging billions of dollars in bets each week on everything from Oscar winners to what words President Trump will say at a press conference to exactly when the bombs will be dropped on Iran – there was even a market on Polymarket that took over betting on when a civil war in the United States might break out.

Tens of millions of people are turning to these sites to try to make money, just as ethical and legal questions haunt the industry. Dozens of new entrants – like Coinbase, Robinhood and even Trump’s social media site Truth Social – are trying to get in on the gold rush, but the world of prediction markets remains dominated for now by two companies: Kalshi and Polymarket.

Media partnership and grocery wars

Mansour and Coplan, who declined to comment for this story, are both billionaires in their 20s and share the belief that the “wisdom of the crowd” philosophy of prediction markets can illuminate truths more quickly and accurately than the media, polls and other traditional institutions.

To achieve this, it was necessary to undertake opposite journeys.

Mansour, 29, a graduate of the Massachusetts Institute of Technology, has worked at Wall Street firms like Goldman Sachs and Citadel. He likes to say that his time on prestigious trading floors made him realize that mass adoption of prediction markets requires playing nice with the federal government, an approach that Kalshi co-founder Luana Lopes Lara, who remains much more discreet, approved.

“We’re literally going to go to the federal government and submit and say, ‘We want to be regulated, and we’re going to bang our heads against the wall until you regulate us,'” Mansour said at last year’s TechCrunch Disrupt conference. “I didn’t want to build a company that suffered from the curse of scale” he said, referring to the idea that a tech startup’s problems could get worse as the company grows.

The curse of scale is hardly a fear for Coplan, a 27-year-old New York University dropout who traded cryptocurrencies as a teenager and launched Polymarket without the blessing of any regulator. He ran the company in a more “shoot first, aim later” style. Raise it quickly, the feds be damned. This approach has not always worked. The FBI raided his Manhattan apartment as part of a Biden-era money laundering investigation. Trump has since dropped the investigation.

“We are just market enthusiasts who believe that prediction markets provide the public with a much-needed alternative data source,” Coplan wrote on X in October 2024, a month before the FBI raid. Just a few months ago, the Trump administration paved the way for Polymarket to open a US-based exchange.

“This is a natural fit in a world where endless opinions are algorithmically served to you based on what you already think, designed only to keep you engaged and push you further into an echo chamber,” Coplan said in the post.

Gouker, a prediction markets consultant, said that when the two men have to sell their ideas in television interviews or at conferences, they can leave divergent impressions.

“Shane is a lot more natural in those settings. He’s an extrovert. You can relate to him,” Gouker said. “But Tarek comes across as a bit pedantic and also in the weeds. He comes across as a fintech guy and not the one leading the prediction markets revolution.”

Taking opposite paths with regulators

Polymarket’s most popular exchange is located overseas and accessible in the United States only through a virtual private network. Traders who received six-figure payments associated with the capture of Venezuelan leader Nicolás Maduro and the death of Iran’s supreme leader have drawn criticism from Washington lawmakers and critics of the apps. Until recently, Polymarket allowed punters to bet money on when a nuclear bomb would detonate. He quietly deleted it after an online outcry.

“Polymarket is much more willing to push the envelope,” the former Kalshi employee said. “Kalshi hates to be confused with Polymarket, but when Polymarket is confused with Kalshi, it’s good for them.”

And that’s because Kalshi negotiated with regulators for years before launching, and he’s now under CFTC scrutiny. During the Biden years, the vast majority of Kalshi’s deals were considered illegal. Today, CFTC Chairman Michael Selig asserted that prediction markets should thrive and largely control themselves.

Selig has even pledged to defend Kalshi in court against states suing the company for violating state gambling laws.

Kalshi has the Trump administration on his side, as does Polymarket. Donald Trump Jr., the president’s son, advises both companies. And his venture capital firm, 1789 Capital, has invested millions of dollars in Polymarket.

The president’s son’s advice may be a commonality, but Mansour is quick to assert that Polymarket is a shady, law-breaking money changer, with Kalshi’s X account often attacking those who are confused. Don’t confuse us, Mansour pleads, even though many users, politicians and commentators regularly confuse them.

As such, businesses have been looking for opportunities to come together.

In early December, Kalshi bragged about his new partnership with CNN. A few weeks later, Polymarket revealed an agreement with The Wall Street Journal publisher Dow Jones.

When Kalshi made a splash last month by giving away $50 worth of free groceries per shopper in New York’s East Village, Polymarket’s Coplan had a response: “New York, we’re open,” Polymarket’s X Account announced, revealing a temporary free grocery store in Manhattan that the company now intends to keep open permanently.

But perhaps nothing crystallizes the feud more than Kalshi’s announcement late last year about the formation of a trade group, called the Coalition for Forecasting Markets, to promote the development of the industry. It describes itself as “a unified industry voice working with policymakers, regulators and the public to establish clear and fair rules that make prediction markets accessible and trustworthy for everyone.”

Absent from the coalition? One of the other largest prediction markets in the world: Polymarket.