U.S. — Kalshi expanded its insider trading monitoring program in May 2026, prompting an investigation by the House Oversight Committee. The company stated it has blocked dozens of trades from campaign insiders. Kalshi spokesperson Jacki McGavick said the company launched more than 150 investigations into potential insider trading, blocked over 100 insider trading moves, and referred at least 20 cases to law enforcement in the first quarter of 2026.

In May, Kalshi introduced a program designed to cross-reference the names of campaign staffers listed in Federal Election Commission data against its user logs. If a potential match is identified, individuals are prevented from placing trades on markets associated with the flagged campaigns, according to Robert DeNault, Kalshi's head of enforcement and legal counsel. DeNault said, "If we're able to identify a potential match, we have markets that are associated with each of the campaigns that are flagged, and those individuals would be prevented from placing trades on those markets."

Despite Kalshi's monitoring program, at least one campaign operative listed in Federal Election Commission records traded on a race in which they were involved. DeNault indicated that the company sets its own platform rules regardless of legislative action, stating, "It is up to us to make rules of the road for our platform, whether Congress does or not." He added, "We've done that here in an expansive way in that we police all campaign individuals, whether they have insider information or not, from placing trades."

The House Oversight Committee is investigating Kalshi and Polymarket regarding their efforts to enforce insider trading rules. This investigation, launched by Representative James Comer, followed a federal indictment in April against a U.S. soldier who allegedly used classified information in January for trading related to a U.S. operation concerning Venezuelan President Nicolás Maduro. Kalshi and Polymarket provided closed-door briefings to the House Oversight Committee in June on their measures to prevent insider trading on their platforms. The Federal Election Commission requires campaigns to list contribution and expenditure data, including some staffer names and addresses. A report from the Brennan Center indicated that election prediction markets have the potential to "fuel misinformation and efforts to influence election outcomes" during the 2026 midterms. In 2026, at least 21 prediction market bills were introduced in Congress, none of which have advanced through either the House or the Senate.

Why It Matters

Kalshi increased its insider trading monitoring, and the House Oversight Committee launched an investigation. The expansion of Kalshi's internal program and the congressional inquiry reflect efforts to address concerns about the integrity of information and financial activity within these platforms. The situation involves a broader conversation among lawmakers and watchdogs, evidenced by the introduction of numerous prediction market bills and reports from organizations like the Brennan Center.