Senate Bans Senators From Trading on Prediction Markets

The Senate unanimously approved S. Res. 708 on Thursday, making the prohibition effective immediately. The resolution, introduced last week by Sen. Bernie Moreno (R-Ohio), amends the chamber’s standing rules that govern member conduct and prevents senators from using prediction markets.

Lawmakers cited concerns about trading on material nonpublic information. The action followed a January wager on Polymarket that bet Venezuelan President Nicolás Maduro would be “out” by the end of the month; the position reportedly netted about $400,000 and prompted a federal probe. Prosecutors later arrested active-duty U.S. Army soldier Gannon Ken Van Dyke, 38, on allegations he used classified information to place that wager; he has pleaded not guilty.

S. Res. 708 bars members from participating in markets that allow wagers on political and real-world events. Sponsors described the rule as a measure to prevent insider trading and to protect public trust. The change modifies existing Senate rules governing conduct rather than creating a new criminal penalty. Enforcement would rely on the Senate ethics process, and sponsors urged the House to consider similar language for representatives.

Prediction market operators have taken steps to address insider trading. Kalshi opened three insider cases last week, penalizing and suspending candidates who bet on their own races. Kalshi founder Tarek Mansour called the resolution a “great step” and urged action in the House: “Now, let’s pass this in the House!” Polymarket posted that its rulebook and terms already prohibit trading on confidential information and that codifying the ban would strengthen market integrity.

At the state level, New York and Illinois recently issued executive orders restricting certain state employees from using nonpublic information to place bets on prediction markets.

Prediction markets have grown as tools for forecasting elections and geopolitical outcomes. Regulators and platforms have raised questions about whether participants with access to nonpublic information could distort market prices or profit unfairly. Market operators report using technology and policy reviews to detect unusual trading patterns and to block accounts tied to prohibited insiders.

Supporters of S. Res. 708 say it clarifies acceptable behavior for senators and aligns legislative ethics with evolving market technology. The resolution represents the first formal, chamber-wide ban on prediction market trading by sitting senators.