Rep. James Comer (R-Ky.), chairman of the House Oversight and Government Reform Committee, announced on CNBC’s “Squawk Box” on Friday that he is seeking information from the CEOs of Carsi and Polymarket about their efforts to prevent insider trading on their platforms.
Comer’s investigation is the latest in a series of attempts by Congress to rein in the platform.
“The internal records maintained by prediction market platforms are the only means by which we can identify bad actors and determine whether the platforms are meeting their legal obligations,” Comer wrote in a letter to Polymarket CEO Shayne Coplan on Friday, seen by CNBC. CNBC also confirmed that a similar letter was sent to Kalsi CEO Tarek Mansour on Friday.
“Accordingly, the Commission requests documentation and information to better understand how Polymarket conducts identity verification of domestic and international account holders, enforces geographic restrictions, and detects anomalous trading activity to prevent insider trading across its global platforms,” Comer’s letter continues.
“We look forward to engaging with the committee and its members about the systems and processes we have developed over the years,” Elizabeth Diana, Carsi’s communications director, said in a statement.
“As a U.S. regulated exchange, we are proud of our comprehensive protections against insider trading,” Diana said.
In an emailed statement, a Polymarket spokesperson said the company “maintains a comprehensive market integrity framework. We look forward to working with Chairman Comer and the committee on how our platform is a pioneer in transparency.”
Representative James Comer, Republican of Kentucky and chairman of the House Oversight and Accountability Committee, speaks to members of the media ahead of a closed-door deposition with Secretary of Commerce Howard Lutnick (not pictured) on Wednesday, May 6, 2026, in Washington, DC.
Al Drago | Bloomberg | Getty Images
Prediction markets like Kalshi and Polymarket have exploded in popularity and are receiving increasing scrutiny from federal and state lawmakers and regulators. Users can bet on the outcome of specific events in a variety of areas, including sports matches, elections, award ceremonies, and government activities.
After a series of highly publicized bets on world affairs and political events, Comer appeared on CNBC and said, “There is concern right now that members of Congress, members of the presidential administration, government officials of all kinds can use basic insider knowledge to make huge profits on all things government-related.”
“So we want to open an investigation to not only see how widespread this is so far, but also to demonstrate that we need to pass some legislation,” Comer said. “And I think it’s fair to say that members of Congress can’t participate in prediction markets, and neither can government employees or people in the presidential administration.”
Calci is headquartered in New York City and regulated by the Commodity Futures Trading Commission. This does not allow users to place bets anonymously. This is a controversial feature of several other platforms operating outside the United States, such as Polymarket.
Although Polymarket also has offices in the US, it is a blockchain-based platform operated by a company licensed in Panama. Although the company has limited U.S. products that are regulated by the CFTC, its international operations are not supervised by U.S. regulators.
Both companies announced earlier this year that they would tighten their own rules on inside insider trading after a series of suspicious trades were made public.
Last month, a U.S. soldier was arrested on suspicion of using inside information to bet on the January ouster of Venezuela’s former leader Nicolas Maduro, winning about $400,000.
A recent New York Times investigation also found that more than 80 Polymarket users placed bets of a questionable nature, including trades made in the hours before the U.S. and Israeli attack on Iran.
“The rapid growth and mainstreaming of this platform, its cryptocurrency infrastructure, and the anonymity it affords its users may have created unintended structural conditions that could be exploited by bad actors, particularly individuals with national security clearance,” Comer wrote to Coplan.
However, Karshi said he does not approve of event contracts related to war or death. However, several political candidates were caught betting on their own elections on stage. In April, Mr. Kalsi suspended three parliamentary candidates who had bet on his candidacy. Mr. Comer mentioned those bets and the company’s expansion into more than 140 countries in his letter to Mr. Kalsi.
“The rapid global expansion of Karshi’s platform raises the question of whether internationally executed event contracts are subject to the same identity verification and insider trading prohibitions as domestic event contracts,” Comer wrote.
A bipartisan group of members of Congress has introduced a flurry of bills this Congress to rein in prediction markets. Some deal specifically with the issue of insider trading, while others are broader and seek to eradicate other activities on the platform, such as sports betting.
Comer’s investigation followed a letter from seven Democrats, led by New Hampshire Rep. Chris Pappas, asking the oversight committee chairman to subpoena the platform.
Democratic lawmakers wrote on May 11: “The American people have a legitimate interest in knowing whether individuals entrusted with sensitive national security information have used that access for personal financial gain. The committee’s subpoena-enforced investigation will include internal records, which are the only means by which we can identify the individuals who made these transactions and answer the question of whether these platforms are upholding their responsibilities.”
In his letter, Comer asked the CEOs to document how the companies verify identities, enforce geo-restrictions and detect anomalous transactions. Comer asked for all information to be submitted by June 5th.
Disclosure: CNBC and Kalsi have a commercial relationship that includes customer acquisition and minority ownership.
