House Oversight and Government Reform Committee Chairman James Comer (R-Ky.) opened a formal congressional investigation Friday into possible insider trading on the prediction market platforms Kalshi and Polymarket, demanding documents from both companies by June 5 and citing what he called a “pattern of suspicious activity” surrounding trades tied to US military strikes in Iran, Venezuela, and the political fallout from both. Comer announced the probe in a live interview on CNBC’s Squawk Box and formally transmitted letters to the CEOs of both companies within hours. The full set of demands was first reported by CNBC in an interview-driven story that has since rocketed across the financial press.
The Comer letters request internal documents related to identity verification systems, enforcement of geographic restrictions on US versus non-US users, monitoring for unusual trade patterns, and what each platform did, if anything, when its own internal surveillance flagged suspicious activity. The probe is the most aggressive congressional move yet against the prediction-market sector, which has expanded into a multi-billion dollar trading category over the last two years on the back of CFTC permission for event contracts at federally regulated exchanges, the explosion of political and geopolitical event volume, and a wave of venture capital backing both Kalshi and Polymarket from firms including Founders Fund, Coatue, and Sequoia.
The trades that triggered the investigation
Comer’s letters reference a recent New York Times investigation that identified more than 80 Polymarket accounts placing concentrated bets with suspicious characteristics, including a cluster of trades placed in the hours immediately before joint US and Israeli strikes against Iranian nuclear and missile facilities during the 2026 Iran war. A separate New York Times reporting thread identified nine linked Polymarket accounts that together cleared more than $2.4 million in profit by betting almost entirely on the timing and outcome of US military actions, with trade timing that mirrored decision points known only to a small circle of US national security personnel.
Comer also cited a January 2026 case in which a US Army soldier was arrested and charged with using inside information about a covert operation against former Venezuelan ruler Nicolas Maduro to place winning Polymarket bets that netted him roughly $400,000 in profit. That case, prosecuted by the US Attorney for the Eastern District of Virginia, established an early prosecutorial template for charging unauthorized disclosure of classified information when the disclosure was made for personal financial gain on a prediction market.
The Comer probe builds on that base. The Oversight Committee is now formally asking whether the prediction market platforms themselves have institutional surveillance and self-reporting protocols sufficient to detect, prevent, and disclose to law enforcement the use of inside information from US government employees, military personnel, contractors, and political insiders. It is the question that the venture-backed prediction market industry has been hoping Congress would not get around to asking.
What Comer is demanding from the companies
The letters to Kalshi CEO Tarek Mansour and Polymarket CEO Shayne Coplan request, among other items, copies of all internal policies governing know-your-customer verification, all internal procedures for flagging unusual trading patterns, all communications between the platforms and the CFTC or other federal agencies regarding suspicious activity reports, internal disciplinary actions taken against users for insider trading or wash trading, geographic restriction enforcement records (Polymarket is technically blocked to US-based users but has historically been criticized for porous geofencing), and a complete list of any congressional candidates, federal employees, or known political operatives who have traded on either platform.
The deadline for compliance is June 5. The Oversight Committee has subpoena power if the companies refuse to produce the documents voluntarily, although Comer has historically preferred negotiated compliance rather than subpoena confrontation in financial-industry probes.
Kalshi’s head of communications said the company would “engage with the Committee and its members about the systems and processes that we have spent years building,” and emphasized that Kalshi is a US-regulated derivatives exchange operating under direct CFTC oversight with robust internal controls. Polymarket’s public response has been more muted. The platform has expanded its compliance team aggressively over the last year under former Justice Department attorney Marjorie Yang and has touted upgrades to its trade surveillance technology, but it remains domiciled outside the US and continues to navigate a complex relationship with American regulators.
The political backdrop
Comer’s probe arrives at a moment of intense congressional scrutiny of the prediction market sector. The US Senate voted in late April to bar sitting senators and their spouses from trading on Kalshi and Polymarket. Senators Adam Schiff (D-Calif.) and John Curtis (R-Utah) introduced bipartisan legislation in March that would require prediction markets to implement specific insider trading detection protocols. Democrats on the Oversight Committee, including Rep. Robert Garcia (D-Calif.), had been pressing Comer for months to use the committee’s investigative authority on this exact question, and the Friday letters represent a rare moment of broad bipartisan agreement on a sector that has otherwise become deeply polarized.
The bipartisan dimension matters. Insider trading on prediction markets is not a culture war issue. Republicans and Democrats both worry that government employees, military personnel, congressional staff, and lobbyists with access to non-public information are using that access to extract profits from event contracts. The fact that Iranian strike timing, Venezuela operations, Federal Reserve rate decisions, election outcomes, and Supreme Court rulings are all directly tradeable on these venues means that the universe of potential insiders is much larger than the universe of insiders that traditional securities markets face. Comer’s letters suggest that the committee intends to map that universe.
For background on how Kalshi and Polymarket actually work, the differences between them, and the regulatory frameworks that govern each, see our deep dive on Kalshi versus Polymarket and our complete guide to Polymarket.
Why the prediction market sector is vulnerable
Polymarket and Kalshi process billions of dollars in event contracts annually. The mechanical structure of these markets means that traders who know the outcome in advance can make extremely large risk-adjusted returns with very small absolute capital, because event contracts pay a fixed $1 on the correct side of a binary outcome. A trader with genuine inside information on, for example, the timing of a US strike on an Iranian nuclear facility can buy “Yes, strike before X date” contracts at twenty cents and collect a dollar each, a five-to-one payout with effectively zero variance if the information is good.
Traditional securities insider trading is hard to make money on quickly because stock prices reflect many variables. Event contract insider trading is dramatically easier, because the resolution is binary and the information often has a sharp time signature. That structural asymmetry is what congressional investigators are now zeroing in on, and it is what the prediction market industry has not yet built fully adequate defenses against.
For more on the structural challenges in prediction market profitability and risk, see our analysis of prediction markets losing money and our piece on Polymarket and Trump executive order betting.
What happens next
The June 5 document deadline is the first inflection point. If Kalshi and Polymarket comply in full, Comer is likely to hold hearings in late June or early July at which executives from both platforms, CFTC officials, and at least one whistleblower or former employee with knowledge of internal compliance gaps will be expected to testify. If either platform pushes back on the document request or attempts to negotiate the scope, expect Comer to issue subpoenas, which carry the threat of contempt referrals.
The likely policy outcomes from a probe of this scale are several. A new federal insider trading statute specifically tailored to event contracts, building on the Schiff-Curtis framework, is one possibility. Enhanced CFTC surveillance authority over Kalshi and over Polymarket’s US-facing affiliate is a near-certainty. Mandatory blackout periods for federal employees and their immediate family on event contracts touching government activities is another likely outcome, modeled on the STOCK Act of 2012 that addressed equity trades by members of Congress.
The deeper question is whether the prediction market sector can demonstrate, under sustained congressional pressure, that it has built genuine compliance infrastructure capable of policing a category of trading that is structurally more exposed to insider abuse than equities, futures, or any other regulated market. Investors who own positions in the prediction market ecosystem, including the public equity holders of FanDuel parent Flutter Entertainment and the venture investors backing Polymarket and Kalshi privately, will be watching the Oversight Committee’s actions extremely closely over the next 60 days.
For broader context on the political and economic forces shaping how prediction markets are used in 2026, see our coverage of Polymarket recession odds.
Frequently Asked Questions
What exactly is James Comer investigating?
Comer is investigating possible insider trading on Kalshi and Polymarket, focusing on trades placed by users who may have had non-public information about US military actions in Iran and Venezuela, election outcomes, Federal Reserve rate decisions, and other events resolved on these platforms. He is also examining whether the platforms themselves have adequate compliance systems to detect, prevent, and report insider trading.
What did the New York Times investigation find?
The Times identified more than 80 Polymarket accounts placing bets with suspicious characteristics, including trades that occurred in the hours immediately before US and Israeli strikes against Iranian facilities. A subset of nine linked accounts collectively profited by more than $2.4 million betting on US military action timing. The reporting was a key driver of Comer’s decision to open a formal probe.
Did anyone actually get arrested for insider trading on these platforms?
Yes. A US Army soldier was charged in January 2026 with using classified information about a covert operation against Nicolas Maduro to place winning Polymarket bets, netting roughly $400,000 in profit. That case became an early prosecutorial template and is referenced directly in Comer’s letters.
What is Comer demanding from Kalshi and Polymarket?
Documents related to identity verification, geographic restriction enforcement, internal surveillance for unusual trades, communications with the CFTC about suspicious activity, any internal disciplinary actions against users, and a list of federal employees, congressional candidates, or political operatives known to have traded on either platform. The deadline for compliance is June 5.
Could this investigation lead to new federal laws?
Yes. The likely policy outcomes include a federal event-contract insider trading statute (potentially building on the bipartisan Schiff-Curtis bill from March), expanded CFTC surveillance authority, mandatory trading blackouts for federal employees on contracts touching government activities, and enhanced KYC and geographic restriction requirements on Polymarket specifically.
Will Kalshi and Polymarket survive this scrutiny?
Both companies will almost certainly survive, but the regulatory and operational environment will tighten significantly. Kalshi, as a CFTC-regulated US exchange, is better positioned to manage the probe. Polymarket faces more complex exposure given its offshore domicile and historical issues with US user access. Expect both platforms to invest aggressively in compliance technology and to add senior government affairs personnel over the next year.
