Who Is Bill Ackman? The £7.2 Billion Investor Urging Trump To Call Off The Economic 'Nuclear Winter'

Billionaire hedge fund manager Bill Ackman, known for his outspoken support for President Donald Trump, has issued a stark warning over the state of the global economy, describing it as teetering on the edge of a 'self-induced economic nuclear winter'.

Ackman, who runs Pershing Square Capital Management, took to social media on Sunday night urging Trump to reconsider sweeping new tariffs, warning that escalating trade tensions could devastate markets and erode investor confidence. In a post shared to his 1.2 million followers, he called for a '90-day timeout' to reassess trade policy, expressing concern that an aggressive stance could lead to an economic breakdown both domestically and internationally.

'The President has an opportunity on Monday to call a time out and have the time to execute on fixing an unfair tariff system,' Ackman wrote. 'Alternatively, we are heading for a self-induced economic nuclear winter, and we should start hunkering down. May cooler heads prevail.'

According to the New York Post, Ackman, despite being a vocal supporter of Trump's economic nationalism, is now warning that the business community is losing faith in the President's approach. He said: 'Business is a confidence game, and confidence depends on trust. What CEO and what board of directors will be comfortable making large, long-term, economic commitments in our country in the middle of an economic nuclear war?'

Ackman warned that disproportionate tariffs imposed across allies and rivals alike could erode the country's reputation as a desirable trade partner and investment destination.

A £7.2 Billion Investor with a Record of Bold Bets

With a personal net worth estimated at £7.2 billion ($9 billion), Ackman is one of the most influential hedge fund managers in the world. He founded Pershing Square Capital Management in 2004 and has built his fortune through high-stakes investments and activist strategies. According to The USA Leaders, the fund manages more than £8.8 billion ($11 billion) in assets as of 2024.

Ackman has become known for targeting undervalued companies and pushing for structural changes to increase shareholder value. His most successful bets include large stakes in Chipotle Mexican Grill, Hilton Worldwide, and Restaurant Brands International, the parent company of Burger King and Popeyes.

He has also invested heavily in Alphabet, the parent of Google, and holds significant interests in real estate through Howard Hughes Holdings, where he owns over 19 million shares. His strategic foresight and sharp business instincts earned him a reported 57% return in 2014, with continued strong performance in recent years.

From Wall Street Star to Economic Watchdog

Ackman's career has not been without controversy. His early hedge fund, Gotham Partners, collapsed in the early 2000s following liquidity issues and regulatory scrutiny. However, he rebounded with the creation of Pershing Square, where his aggressive and highly publicised positions have kept him in the spotlight.

According to The Motley Fool, Ackman also made headlines during the COVID-19 pandemic by turning a £21.4 million ($27 million) credit default swap into a £2 billion ($2.6 billion) profit, drawing criticism for allegedly fearmongering during the market panic.

Despite past criticisms, Ackman has increasingly taken on a more cautious tone when it comes to government policy. His recent plea to Trump signals growing concern among elite financiers that heavy-handed protectionist policies could send markets into chaos and inflict long-term damage on consumer confidence and corporate spending.

'When markets crash, new investment stops, consumers stop spending money, and businesses have no choice but to curtail investment and fire workers,' Ackman wrote. 'And it is not just the big companies that will suffer. Small and medium-sized businesses and entrepreneurs will experience much greater pain.'

He added that the steep costs of a trade war would be borne most heavily by low-income Americans already struggling with economic pressures. 'This is not what we voted for,' he said.

Ackman's warning comes as Trump prepares to enact a new 10% blanket tariff on imports. While the move is being billed as a negotiation tactic, the President has indicated the tariffs could remain permanent—raising the spectre of a full-blown trade war just months before the US election.

As one of Wall Street's most powerful figures, Ackman's shift in tone may serve as a signal to other business leaders who are quietly uneasy about the direction of US trade policy. Whether Trump heeds the call remains to be seen, but the message is clear: confidence is cracking, and the stakes could not be higher.