The White House has warned staff against placing bets on prediction markets, following reports of insider trading concerns. The Wall Street Journal first reported the email sent to staff members on Thursday. Government ethics guidelines prohibit federal employees from using insider information for financial gain, according to White House communications.

Polymarket came under scrutiny in January after a gambler made nearly $500,000 on the capture of Venezuelan president Nicolás Maduro before the official announcement. The anonymous account, identified only by a blockchain address, raised questions about potential insider knowledge of US military operations. Kalshi and Polymarket have been contacted for comment on the new restrictions.

Prediction markets, which host more than $44 billion in trades, have grown increasingly popular for betting on political and economic events. Users can wager on outcomes ranging from sports to Federal Reserve decisions and election results. The White House's warning signals growing concerns about the integrity of these platforms and the potential for insider trading.