Bill Ackman: Activist Investor, Big Wins and Bigger Fights

From Gotham to Pershing Square

William Ackman was born in 1966 in Chappaqua, New York, and studied at Harvard, earning a bachelor’s degree in 1988 and later an MBA from Harvard Business School. In 1992 he co-founded his first investment firm, Gotham Partners, with David Berkowitz. It started with about $3 million and was wound down in the early 2000s after a run of problems. In 2004 he started again, founding Pershing Square Capital Management with $54 million.

How Ackman invests

Ackman’s style mixes value investing with activism. He buys large stakes in a small number of big, well-known companies, usually around ten at a time, and then pushes management, publicly if he thinks it necessary, to change strategy, sell businesses, cut costs or replace executives.

• Concentration: a handful of large positions, each big enough to matter.
• Quality: simple, predictable businesses with strong brands or pricing power, such as restaurant chains, hotels and railways.
• Engagement: board seats, presentations and open letters to push for change.
• Hedges: occasional large, cheap bets that pay off if markets fall sharply.

Some of his best-known successes came this way. At Canadian Pacific Railway he won a proxy fight in 2012 and brought in new management; he invested in Chipotle in 2016, after a series of food-safety scares had hit its shares; and he held Hilton through the pandemic and its recovery.

$2.6 billion in a month, and billions lost

In early March 2020, as Covid-19 spread, Ackman spent about $27 million on credit protection, a hedge that would pay out if corporate bond markets panicked. They did, and by 23 March he had cashed out with about $2.6 billion, roughly 100 times his outlay. He then used most of the money to buy more of the companies he already owned.

His losses have been just as public. In 2012 he announced a $1 billion bet against Herbalife, accusing the nutritional supplements company of being a pyramid scheme. The company denied it, Carl Icahn bought shares on the other side, the price rose, and Ackman finally exited in 2018 with heavy losses. His investment in Valeant Pharmaceuticals, whose shares collapsed in 2015 and 2016 amid scrutiny of its drug pricing and accounting, cost Pershing Square roughly $4 billion. And a blank-cheque company he launched in 2020, Pershing Square Tontine Holdings, raised $4 billion but never completed a deal and returned the money in 2022.

Ackman’s career shows that concentrated, high-conviction investing magnifies everything: the right bet can make billions in weeks, and the wrong one can cost billions over years.

Building a “modern-day Berkshire”

In 2022 Ackman said he would stop running activist short-selling campaigns and focus on long-term holdings. His main listed fund, Pershing Square Holdings, has traded in Europe since 2014, first in Amsterdam and later in London, where it joined the FTSE 100, and Pershing Square reported a net return of 20.9% for 2025. In May 2025 Pershing Square paid $900 million for newly issued shares of Howard Hughes Holdings, a property developer, gaining control with Ackman as executive chairman. He has described the plan as a modern-day version of Berkshire Hathaway: a company that serves as a permanent home for long-term investments.

In April 2026 he took the next step. Pershing Square USA, a new closed-end fund, raised $5 billion at $50 a share and began trading on the New York Stock Exchange on 29 April under the ticker PSUS, while the management company itself, Pershing Square Inc., listed under the ticker PS. Buyers of the fund received free shares in the manager as a sweetener. It was a bumpy start: PSUS opened about 16% below its offer price, at around $42.

What investors can learn

Ackman’s best results came from deep research and the patience to hold great businesses through bad news. His biggest losses came from bets where he was both heavily concentrated and very public, which made it harder to change his mind. For ordinary investors, the practical lesson is about structure as much as about the manager: closed-end funds and investment trusts like his trade on the stock market and can sit at a large discount to the value of what they own, so the price you pay matters. This profile is general education, not a recommendation to buy any fund or share.

This article is educational and general in nature. It isn’t personalized investment, tax, or legal advice — always weigh your own circumstances, or talk to a licensed professional, before making financial decisions.

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