California Governor Gavin Newsom has signed a ban preventing state officials from using insider knowledge to trade on prediction markets, according to reporting from Politico and Forbes.
The measure targets platforms including Kalshi and Polymarket, which allow users to wager on the outcomes of political, economic and other real-world events. Prediction markets have expanded sharply in the United States following regulatory decisions that permitted event-contract trading, drawing scrutiny over whether government insiders could profit from information unavailable to the public.
Newsom's office signalled the move with an attention-grabbing social media post directed at Kalshi and Polymarket, asking about the odds of the governor banning officials from such activity, before confirming the action.
The specific enforcement mechanism and penalties were not detailed in the available reporting. It is also unclear whether the ban extends to family members or close associates of covered officials, a common question in analogous insider-trading rules that apply to elected representatives at the federal level.
