Prediction markets are facing accusations of insider betting tied to the White House, which is bad news for anyone who assumed these markets are clean.

• Donald Trump Jr. has advised both Kalshi and Polymarket, the two big prediction market platforms.
• One market let people bet on how long a White House press briefing would run.
• Press secretary Karoline Leavitt ended the briefing seconds before the popular bet would have paid out.
• Anyone betting the other side could have won roughly 20 times their money.

Outlook: Expect more scrutiny of who inside government can move prediction market odds, and pressure for rules on political insiders betting on their own events.