Prediction market Kalshi helped tee up a November 2024 FBI raid on the apartment of its arch-rival Polymarket’s CEO – part of a series of blows the companies have traded during their yearslong feud, according to a report that cited Polymarket sources.

Before the raid, Kalshi attorneys met with prosecutors in Manhattan to amplify their concerns about Polymarket’s business, the New York Times reported. In those meetings, the lawyers reportedly detailed to officials how Polymarket’s platform operates, including how US users could still access its markets despite restrictions intended to keep Americans off the site.  

Not long after, FBI agents used a battering ram to bust into Polymarket founder and CEO Shayne Coplan’s apartment before dawn on Nov. 13, 2024 — part of an investigation into whether Polymarket illegally allowed Americans to place bets on its platform.

FBI agents burst into the apartment of Polymarket founder and CEO Shayne Coplan in 2024. Zuffa LLC

Coplan publicly called the search nothing more than political retaliation by the Biden administration. But privately, he and other Polymarket executives reportedly grew convinced that Kalshi’s top brass had helped put federal investigators on their trail.

Polymarket execs speculated that someone working for Kalshi — or acting on its behalf — had tailed Coplan, spotted federal agents outside his apartment on the day of the raid and quickly tipped off journalists to get the news to spread quickly, the Times reported.

The anecdote was just one of the examples of the brutal tit-for-tat between the New York-based startups as they battle for pole position in the burgeoning prediction market sector. Both platforms allow users to bet on everything from the weather and geopolitical events to sports.

Kalshi is led by co-founders and co-CEOs Tarek Mansour and Luana Lopes Lara, who met while studying at the Massachusetts Institute of Technology and started the company in 2018.

The bad blood between them and Coplan, who launched Polymarket in 2020, stretches back years. During one early meeting, Coplan tried to establish common ground by noting that he and Mansour were both raised by single mothers, a comment which made Mansour uncomfortable, according to the Times.

Kalshi spokeswoman Elisabeth Diana told the Times that Kalshi’s involvement in the FBI raid was a “complete lie” and that Polymarket was exhibiting a “truly bizarre level of paranoia.”

She added that Kalshi only learned about the FBI search through media coverage and said the company regularly communicates with regulators about industry compliance.

Kalshi has repeatedly warned officials about what it views as Polymarket’s regulatory shortcomings, Diana said.

Kalshi co-founder and co-CEO Tarek Mansour has been engaged in a heated rivalry with Polymarket. Bloomberg via Getty Images

After the raid, tech blog Pirate Wires published screenshots showing Kalshi employee Keaton Inglis encouraging former NFL star Antonio Brown to post on X accusing Coplan of being “guilty.” 

The blog posted text messages showing Inglis, a member of Kalshi’s growth team, asking Brown to post to his 2.2 million X followers: “this n—a seems guilty,” using a racial slur in reference to a photo of Coplan. Brown posted the message shortly after. 

Brown later walked back the post, saying he had been “doing other business with Kalshi and just tweeted it.” Mansour later acknowledged the incident on a podcast, saying some members of his team had “got pretty heated.”

Diana downplayed the bad blood between the CEOs in a statement to the Times. 

“The only issue Tarek has with Shayne is his reckless approach to an industry that Kalshi has spent years getting regulated,” she said, adding that Mansour has “no personal animosity” toward his rival.

A Polymarket spokeswoman shared with the Times a statement about Mansour, a quote by Ralph Waldo Emerson: “The louder he talked of his honor, the faster we counted our spoons.”

Kalshi operates under CFTC regulations while Polymarket operates a significant portion of its business offshore. Polymarket has a limited US product that is subject to CFTC regulations. Christopher Sadowski for NY Post

The Post reported last month that Polymarket had launched an internal investigation to find the source of what it believed to be product leaks to Kalshi. Coplan’s company even amassed a dossier that detailed what it considered to be suspicious incidents that pointed to the possibility that there was Kalshi mole in its offices. 

Kalshi denied the allegations at the time.

The increasingly bitter feud comes as both companies face mounting legal challenges. Kalshi and Polymarket are fighting lawsuits and regulatory actions from multiple state attorneys general who argue their sports prediction products amount to illegal gambling. Polymarket is also under investigation by the Commodity Futures Trading Commission, the US regulator that polices prediction markets.

Kalshi operates under CFTC regulations while Polymarket operates a significant portion of its business offshore. Polymarket has a limited US product that is subject to CFTC regulations.

The Post has sought comment from Kalshi and Polymarket.