Billionaires in the US have been spooked by the possibility that economic life under Donald Trump might not be all sweetness and light. Consider Stanley Druckenmiller. Famous for working with George Soros (shorting sterling in 1992, when Soros broke the Bank of England, was Druckenmiller’s idea) and one of history’s most successful investors, Druckenmiller is obviously smart, but he didn’t see the risks posed by Trump. “I’ve been doing this for 49 years, and we’re probably going from the most anti-business administration to the opposite”, he said in January. A believer in “animal spirits”, he said chief executives were “somewhere between relieved and giddy”, while “the risks [from tariffs] are overblown relative to the rewards”. READ MORE Druckenmiller was less exuberant after Trump announced sky-high tariffs and all hell broke loose, making a rare social media post to note he did “not support tariffs exceeding 10%”. He presumably believed in January that US treasury secretary Scott Bessent, who once worked for Druckenmiller, would keep Trump on a leash. As it happens, Bessent reportedly did play a key role in Trump’s eventual tariff climbdown. Still, Trump’s recklessness and impulsivity will have alarmed many one-time supporters in the investment community. Fundstrat founder Tom Lee, long regarded as one of Wall Street’s biggest bulls, said he has had “many conversations with macro fund managers”, and “a few have quietly wondered if the president might be insane.” In the end, the enormous relief rally that followed Trump’s climbdown said a lot: for worried billionaires and investors alike, even a semblance of rationality from the president was enough to send stocks soaring.