Bill Ackman said he would be “would be surprised if deposit outflows don’t accelerate effective immediately.”: Hedge fund billionaire Bill Ackman says the U.S. economy risks heading for a “train wreck,” following Wednesday’s interest rate hike and comments from U.S. Secretary of the Treasury Janet Yellen pushing against universal guarantees for banks. “We have gone from implicit support for depositors to [Secretary Yellen’s] explicit statement today that no guarantee is being considered,” the founder of Pershing Square Capital Management tweeted on Wednesday.