Kentucky lawmaker expands investigation into insider trading on prediction markets

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2026/05/22: House Committee to probe prediction market insider trading on Kalshi, Polymarket 2026/08/05: Trump’s Truth API service faces backlash over insider trading concerns 2026/03/25: Kalshi and Polymarket introduce new insider trading restrictions 2026/05/01: Polymarket partners with Chainalysis on insider trading detection

The Backstory

Washington’s prediction-market scrutiny broadens

The House Oversight Committee’s inquiry into prediction-market insider trading has moved from a targeted review of two marquee platforms into a wider examination of the industry’s controls. Rep. James Comer, the Kentucky Republican who chairs the committee, is now seeking information from Hyperliquid Labs, Crypto.com and Aristotle Exchange, the owner of PredictIt, about how they verify users, enforce know-your-customer rules and detect suspicious trading.

The expansion builds on the committee’s earlier inquiry into Kalshi and Polymarket, two platforms that have become central to the debate over whether event contracts can be policed effectively when the underlying outcomes may be known to government employees, corporate insiders or people close to decision-makers. In May, Comer opened a House probe into prediction-market insider trading on Kalshi and Polymarket, seeking documents on identity checks, geographic restrictions and surveillance systems. The committee set a June 5 response deadline and focused on whether people with access to confidential government information could profit from markets tied to policy, geopolitics or official actions.

That initial probe came as prediction markets were gaining mainstream attention and political relevance. Platforms allow users to trade contracts tied to the outcome of events, from elections and court rulings to sports, corporate developments and international affairs. Supporters say they aggregate public expectations and create real-time signals. Critics say the same mechanisms create powerful incentives for people with nonpublic information to trade before news becomes public.

Kalshi and Polymarket became early test cases

The first wave of congressional scrutiny centered on Kalshi and Polymarket because they illustrate the two sides of the market’s growth. Kalshi operates as a regulated U.S. exchange for event contracts, while Polymarket built its business on blockchain-based markets that became popular around elections and geopolitical outcomes. Both have argued that transparent markets can improve information flow, but both have faced questions over who is allowed to trade and what happens when traders know more than the public.

The committee’s interest followed several incidents that sharpened concerns in Washington. A U.S. soldier was arrested in April over allegations that he used confidential information to trade on Polymarket contracts concerning the removal of former Venezuelan leader Nicolás Maduro. Reports also identified unusual activity before military developments involving Iran. Those cases gave lawmakers concrete examples of the risk Comer described: government employees or contractors using official access to profit from event contracts.

Industry practices also came under pressure after the New York Times reported that more than 80 Polymarket accounts showed potentially suspicious betting patterns. Separately, Kalshi permanently banned former Rep. George Santos in August and imposed a $71,356 fine for allegedly using the platform to wager on whether he would attend the 2026 State of the Union address. The Santos case underscored a central challenge for the industry: prediction markets can involve outcomes in which public figures, staff members or associates may have direct influence or advance knowledge.

Platforms respond with new surveillance tools

The compliance response has accelerated as lawmakers have increased pressure. Kalshi and Polymarket in March announced new insider-trading restrictions for prediction markets, with Kalshi saying it would block politicians, athletes and other relevant figures from certain markets. The company also said it would add whistleblower tools to market pages so users could flag possible violations visible in public trading data.

Polymarket updated its integrity rules to define prohibited conduct more clearly, including trading on stolen or confidential information, acting on illegal tips and trading by people who can influence outcomes. The changes were intended to answer a basic question regulators and lawmakers have been asking: whether prediction platforms can distinguish legitimate forecasting from trades rooted in privileged access.

Those moves did not satisfy all critics. Rep. Alexandria Ocasio-Cortez said Kalshi’s restrictions were not enough, arguing that staff, advisers, consultants, cabinet secretaries, spouses and others could still have access to valuable nonpublic information. Her criticism pointed to a broader enforcement problem. Even if platforms bar obvious insiders, networks of aides, family members and intermediaries may still create channels for improper trading.

Polymarket later deepened its compliance infrastructure through a partnership with Chainalysis on insider-trading detection. The agreement gave Polymarket access to blockchain investigative tools, on-chain security services, staff training and support for investigations. Because Polymarket trades and settlements are recorded on a blockchain, the company has argued that open records can make surveillance more effective than in traditional markets. The question for policymakers is whether transparency after the fact is enough to deter trading before material information is public.

Market design creates built-in conflicts

The insider-trading debate is not limited to elections or government actions. Prediction markets have increasingly listed contracts tied to commercial events where many people may already know the answer. Ahead of Super Bowl LX, Kalshi and Polymarket offered contracts on advertisements expected to air during the game, raising concerns over event contracts tied to Super Bowl ads. The concern was straightforward: unlike the outcome of a football game, advertising lineups are known in advance by brands, agencies, production companies, broadcasters and other vendors.

That type of market highlights a structural weakness. The more an event depends on planned decisions rather than uncertain competition, the larger the circle of people who may know the outcome. A contract on whether a celebrity appears in an ad, a company announces a product or a government official attends an event may be framed as a prediction. But for insiders, it can be a fact waiting to be monetized.

The issue also tests the capacity of the Commodity Futures Trading Commission, the main federal regulator overseeing U.S. event-contract markets. Industry advocates have called for stronger federal standards rather than fragmented enforcement, while skeptics question whether the agency has enough resources to monitor the speed and volume of trading across platforms, especially as markets move into politics, sports-adjacent events and corporate developments.

Politics, access and faster information flows

The debate intensified when President Donald Trump’s Truth Social introduced Truth API, a paid service offering faster access to posts from high-ranking accounts. The rollout triggered backlash over insider-trading concerns tied to Truth API, because market-moving posts from senior political figures could affect securities, cryptocurrencies or prediction contracts linked to policy and political events.

Sen. Alex Padilla, a California Democrat, said he would introduce legislation to prohibit paid presidential post subscription services, arguing that premium access to presidential communications could advantage hedge funds, banks and other institutional subscribers. The concern overlaps with the prediction-market inquiry: if traders can pay for faster access to influential political information, or obtain it through official channels before the public, markets may reward proximity to power rather than forecasting skill.

The Truth API dispute broadened the insider-trading discussion beyond the platforms themselves. It raised questions about the information ecosystem feeding those markets, including government communications, social media infrastructure, data vendors and private subscriptions. Even robust platform surveillance may miss a trade that appears normal unless the operator can identify how the trader obtained an informational edge.

The stakes for a growing industry

Comer’s expanded inquiry signals that Congress is no longer treating insider trading as a problem limited to a handful of high-profile platforms. By asking additional operators for compliance records, lawmakers are testing whether the industry has baseline safeguards or whether rules vary widely by venue. The nearly 1,000 documents and five briefings already received from Kalshi and Polymarket give the committee a foundation to compare practices across newer or adjacent platforms.

The stakes are regulatory and commercial. Prediction markets are pushing into areas traditionally handled by polling, financial derivatives, sports betting and political analysis. Their credibility depends on users believing prices reflect dispersed public judgment, not trades by people with inside access. If lawmakers conclude platforms cannot prevent abuse, they could seek tighter limits on who can trade, which events can be listed and how operators must monitor activity.

For the platforms, the challenge is to preserve the speed and openness that make prediction markets attractive while satisfying demands for market integrity. The latest congressional requests show that voluntary guardrails, blockchain transparency and updated rules have not ended the debate. They have instead become evidence in a larger question now facing Washington: whether prediction markets can be integrated into the financial system without turning nonpublic information into a tradable asset.