A billionaire backer of Donald Trump has urged the US president to pause his recently announced trade tariffs, or risk “a self-induced, economic nuclear winter”.
Amid market turmoil, hedge fund manager Bill Ackman said the president should take three months to allow countries to renegotiate their trading relationships with the US.
On Monday, Mr Ackman’s warning was echoed by another prominent Wall Street figure, with JPMorgan Chase chairman Jamie Dimon saying that Trump’s tariffs risked pushing up prices for Americans.
Despite the shockwaves, the American president has defended his new import taxes, saying “sometimes you have to take medicine to fix something”.
He says the move will boost his country with new jobs and investment, but economists warn that prices could rise for Americans and spark a trade war.
Share prices in Europe and Asia continued to plummet on Monday, as markets react to the sweeping, global tariffs announced by Trump last week.
In his post on X on Sunday, Mr Ackman acknowledged the Trump argument that the global trade system had “disadvantaged” the US.
But, he wrote, tariffs that Trump had imposed were “massive and disproportionate”, and did not distinguish between American friends and enemies.
Mr Ackman, the billionaire founder of Pershing Square hedge fund management company, became a high-profile supporter of Trump, a Republican, in July 2024.
He had previously backed the rival Democratic Party, and his intervention was seen as an important electoral endorsement from the world of business.
