White House staff prediction market trading controls, Warren and Merkley demand disclosure

Democratic Senators Elizabeth Warren and Jeff Merkley sent a letter to White House counsel Will Scharf demanding disclosure of the internal rules governing staff trading on prediction markets, after an employee who previewed a Trump speech reportedly traded on its contents. The letter asks whether staff receive training on prediction-market rules and what procedures prevent them from trading on nonpublic information. The dispute matters because prediction markets such as Polymarket and Kalshi settle real money on event outcomes, and clearer White House guardrails could set a precedent for how insider knowledge is handled across the fast-growing sector. What to watch next is the White House's written response to the senators and whether it publishes formal trading policies for staff.