House Panel Launches Investigation Into Insider Trading on Kalshi and Polymarket Prediction Markets

Congressional Probe Targets Prediction Market Platforms

House Oversight Committee Chairman James Comer formally launched a congressional investigation on May 22, 2026, into alleged insider trading on prediction market platforms, demanding internal records from the chief executive officers of both Kalshi and Polymarket. The investigation marks the latest escalation in Washington\'s scrutiny of rapidly growing prediction markets that allow traders to wager on political events, economic indicators, and sporting outcomes.

The probe was prompted by concerns that government employees may be using classified or non-public information to trade on prediction markets, according to documents from the House Committee on Oversight and Accountability. Comer\'s committee has requested records detailing how both platforms detect and respond to anomalous trading activity.

Regulatory Precedents Set Earlier in 2026

The congressional investigation follows a series of enforcement actions by federal regulators throughout 2026. The Commodity Futures Trading Commission (CFTC) issued an advisory in February 2026 addressing insider trading on prediction markets following the public release of enforcement cases. In April 2026, the Department of Justice (DOJ) and CFTC brought a first-of-its-kind prediction market insider trading case, marking a significant milestone in regulatory oversight of these platforms.

Separately, Kalshi has taken its own enforcement actions, fining and suspending three political candidates for trading on their own races during primary campaigns, according to Yahoo Finance. The platform\'s actions demonstrate that compliance concerns extend beyond government officials to candidates seeking to profit from market movements in their own elections.

Explosive Volume Growth Draws Lawmaker Attention

The congressional scrutiny coincides with unprecedented growth in prediction market activity. Monthly transaction volume across prediction markets grew from approximately USD 1.2 billion in early 2025 to over USD 20 billion in January 2026, according to TRM Labs data. Annual trading volume climbed from USD 15.8 billion in 2024 to approximately USD 63.5 billion in 2025, with volumes growing nearly four times sequentially, according to LinkedIn analysis.

Weekly prediction market volume reached a high-water mark above USD 2 billion, while platforms are on pace to exceed USD 325 billion in 2026 based on year-to-date run-rate volumes, according to projections cited in industry analysis. Within the competitive landscape, Kalshi surpassed Polymarket in trading volume in October with USD 4.4 billion versus USD 4.1 billion, according to CryptoRank data.

Kalshi\'s markets for the 2026 PGA Championship topped USD 365.2 million in volume, illustrating the appetite for non-political prediction contracts, according to DeFi Rate data.

Senate Momentum Builds for Legislative Action

Beyond the House investigation, momentum is building in the Senate to restrict lawmakers and officials with insider access from trading on prediction markets, according to News Channel 9. The legislative push reflects bipartisan concern that government employees with access to non-public information could exploit prediction markets for personal gain.

The Third Circuit Court of Appeals also weighed in on prediction market regulation in April 2026, affirming a preliminary injunction preventing New Jersey from enforcing its gambling laws against Kalshi\'s sports-related event contracts, according to Norton Rose Fulbright analysis. The ruling provides clarity on the regulatory distinction between prediction markets and traditional gambling under federal law.

Industry Perspectives on Market Integrity

Economist Robin Hanson, a prominent voice in prediction market theory, has emphasized the importance of accurate pricing in these markets. "You want the most accurate prices. That\'s pretty clear. The purpose of the market is to inform decisions," Hanson stated in April 2026, according to Fortune.

Prediction market operators argue that their platforms aggregate information more efficiently than traditional forecasting methods, but critics contend that without robust safeguards, insider trading could undermine market integrity and public trust.

Implications for Markets and Regulation

The congressional investigation signals that prediction markets have grown large enough to attract serious regulatory attention. With annual volumes approaching USD 65 billion and monthly volumes exceeding USD 20 billion, these platforms now represent a significant segment of financial markets that regulators view as requiring oversight.

For traders and investors, the investigation highlights compliance risks that could affect market access and trading strategies. Platforms may face heightened requirements to implement surveillance systems capable of detecting insider trading patterns.

The outcome of the investigation could shape how prediction markets operate in the United States, potentially leading to new disclosure requirements for government employees or enhanced reporting obligations for platforms.

Coinasity\'s Take

The congressional investigation into prediction market insider trading represents a pivotal moment for an industry that has grown from a niche financial experiment into a multi-billion-dollar market attracting mainstream attention. The timing is notable: regulators and lawmakers are responding to the same explosive volume growth that demonstrates prediction markets\' commercial viability. For the sector to mature, platforms must demonstrate that they can self-regulate effectively or face mandatory compliance frameworks that could reshape competitive dynamics. The coming months will test whether Kalshi, Polymarket, and competitors can satisfy congressional demands while preserving the market efficiency that has driven their growth.