Bill Ackman

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Bill Ackman
BornWilliam Albert Ackman
5/11/1966
BirthplaceChappaqua, New York, U.S.
NationalityAmerican
OccupationHedge fund manager
TitleFounder and CEO, Pershing Square Capital Management
Known forActivist investing, Pershing Square Capital Management
EducationHarvard University (BA, MBA)
Spouse(s)Karen Ann Herskovitz (m. 1994; div.)
Neri Oxman (m. 2019)
Websitehttps://www.pershingsquareholdings.com/

William Albert Ackman (born May 11, 1966), known as Bill Ackman, is an American billionaire hedge fund manager, activist investor, and philanthropist. He founded and runs Pershing Square Capital Management, a New York City-based investment management company.[1] His whole career revolves around making large, concentrated bets on publicly traded companies and taking activist positions to push for changes in how they're run. He'll go after corporate governance, strategy, management. Whatever he thinks needs fixing. His campaigns have made him one of Wall Street's most watched figures, winning some big battles and losing others just as publicly. On the wins side: Canadian Pacific Railway. On the losses: Valeant Pharmaceuticals and J.C. Penney.[2] He spent years backing Democratic candidates and causes. Then in 2024, that changed. He endorsed Donald Trump in the 2024 United States presidential election. These days he's become much more outspoken on politics, higher education, and geopolitical affairs, especially after the October 7, 2023, attacks on Israel. As of early 2026, Pershing Square's holdings shifted significantly toward technology, with Ackman making a big splash with a large new stake in Meta Platforms.[3]

Early Life

William Albert Ackman was born on May 11, 1966, in Chappaqua, New York. It's an affluent hamlet in Westchester County.[4] He grew up in a Jewish family with deep roots in New York's business world. His father, Lawrence D. Ackman, worked as a real estate financier and chaired a New York mortgage company. Lawrence married Ronnie I. Posner in 1963.[5]

Real estate and finance surrounded him growing up. It shaped him early. That environment pushed him toward investing and business from the start, with his family's New York real estate connections influencing his early career path and his initial interest in real estate-related deals. Chappaqua itself, a suburb known for top-tier public schools, gave him a stable, privileged upbringing.

His father was huge. Ackman has said so himself, crediting him with passing down an understanding of business and deal-making when he was just a kid. The drive and analytical mind that'd later define his activist approach showed up even then, during his formative years.

Education

He went to Harvard College for his Bachelor of Arts degree, then on to Harvard Business School where he picked up a Master of Business Administration (MBA).[6] Harvard shaped how he thought about investing and linked him with other people who'd become major players in finance.

That Harvard diploma has stuck with him. He's stayed connected to the school over the years, though things got rocky in recent years when he went public criticizing Harvard's leadership during the 2023-2024 campus controversies involving the Israel-Hamas war.

Career

Early Career and Gotham Partners

Right after finishing his MBA, Ackman jumped into investing. In 1992, he and David P. Berkowitz, another Harvard grad, started Gotham Partners Management. A small investment firm. It focused on public and private companies, leaning hard into real estate. The financial press noticed. Ackman built a reputation fast as aggressive and rigorous.[7]

The firm grew through the 1990s but ran into trouble. Heavy investments in illiquid assets and concentrated positions created problems when markets shifted. By the early 2000s, investors were pulling out and regulators were looking closer. Gotham eventually shut down. It hurt, but it taught him lessons that mattered: liquidity risk, portfolio concentration, how to handle investors. He'd apply all of it to what came next.

Pershing Square Capital Management

Ackman founded Pershing Square Capital Management in 2004, and it became one of the world's biggest activist hedge funds.[1] The name came from Pershing Square, a public plaza next to Grand Central Terminal in Manhattan. The firm's whole structure was built for concentrated portfolios: big positions in a small number of companies where Ackman thought he could make things better. Better operations. Better strategy. Better governance.

What set Pershing Square apart was how willing it was to take huge public positions and push hard for change. Ackman's known for research presentations that run dozens or hundreds of pages, laying everything out in obsessive detail. That made him one of his generation's most prominent activist investors.[2]

The firm also launched Pershing Square Holdings, a closed-end fund on the Euronext Amsterdam exchange, giving more investors access to Ackman's strategy.[1]

Notable Investment Campaigns

His time at Pershing Square has been one big series of high-profile campaigns. Some won big. Some lost big.

Canadian Pacific Railway was one of his best calls. Pershing Square took a major stake and pushed for management changes. That led to new leadership and a turnaround that made serious money for investors.

Then there was J.C. Penney. Ackman took a huge position and bet the whole thing could be transformed. New business model. New CEO. It didn't work. He quit the board in August 2013 after disagreeing with where the company was headed.[8] Heavy losses on that one.

His Herbalife short. That's the one that defined a generation of Wall Street drama. In December 2012, Ackman dropped $1 billion shorting Herbalife, calling it a pyramid scheme and piling on the evidence. It turned into one of the wildest investment feuds ever, partly because he went toe-to-toe publicly with Carl Icahn, who bet the other way. The short lost money. Ackman closed it years later after taking a hit.

Valeant Pharmaceuticals (later Bausch Health) was another disaster. Ackman took a big stake, joined the board, watched the company acquire other pharma firms and jack up prices. Regulators came down hard. Congress got involved. The stock tanked. Pershing Square got crushed. Ackman dumped the whole position.[9]

But his overall record at Pershing Square included some exceptional periods. In 2015, his returns ranked him in the top 20 hedge fund managers.[2] He also made an incredibly profitable bet at the start of the COVID-19 pandemic in early 2020 when he bought credit default swaps that made about $2.6 billion in a few weeks as markets crashed.

Recent Investments and AI Focus

By 2026, Ackman shifted Pershing Square's portfolio to catch emerging market themes, particularly technology and artificial intelligence. In February 2026, Pershing Square revealed a big new stake in Meta Platforms, which owns Facebook, Instagram, and WhatsApp. Ackman told investors Meta had a "deeply discounted valuation" and felt confident about its position in the AI space.[3]

The Meta move fit a bigger pattern. Ackman's portfolio was moving into AI-related companies generally. His 13F filings showed moves into firms that'd benefit from AI growth.[10] Other investors and analysts watched the Meta position closely, noting the strong conviction behind it.[11]

Ackman also went into private tech deals. In January 2026, he joined Satya Nadella and the venture firm Iconiq Capital in funding a $40 million round for Outtake, an AI security startup building agentic AI tools.[12]

Pershing Square IPO Efforts

In 2024, Ackman said he'd take part of Pershing Square public through a U.S.-listed closed-end fund. It'd be one of the biggest IPOs of its kind. Market conditions shifted things. Investor interest evolved. But the core idea stayed: get more people invested in Pershing Square and build a more permanent capital structure.

Political Activities and Public Commentary

Democratic Party Ties and Shift to Republican Support

Most of his career, Ackman backed Democrats. Donations to candidates, organizations, the whole thing. Then 2024 came. He endorsed Donald Trump in the 2024 United States presidential election. Big shift. Media went wild covering it.

After Trump won, Ackman stayed engaged but didn't hold back criticism when he disagreed. In January 2026, Trump proposed capping credit card interest rates at 10 percent for a year. Ackman went public calling it a "mistake" and warning about unintended consequences for how available credit would become.[13]

Immigration enforcement became another focus. In January 2026, Ackman gave $10,000 to a GoFundMe for Jonathan Ross, an ICE agent involved in a controversial shooting in Minneapolis where a woman named Renee Nicole Good was killed. People criticized it. Ackman defended himself publicly.[14][15]

Israel Advocacy and Higher Education Criticism

After October 7, 2023, Ackman became one of America's loudest business voices on Israel and antisemitism. He blasted what he saw as antisemitism on university campuses. The pro-Palestinian protests in 2024 crossed a line, he argued, from politics into harassment.

When Claudine Gay, Harvard's president, testified to Congress on campus antisemitism, Ackman went after her. He ran a sustained public campaign, mostly on X, calling for her resignation. Many observers credited him as a significant reason she eventually stepped down.

Tax Policy Debates

Ackman's wealth and prominence made him a target in tax debates. In February 2026, Senator Bernie Sanders called out Ackman alongside Elon Musk and Peter Thiel, demanding billionaires pay their "fair share" in taxes, particularly for a proposed California wealth tax.[16]

Personal Life

Ackman married Karen Ann Herskovitz in July 1994. She had a degree in landscape architecture.[17] They had kids together before divorcing.

In 2018, reports said Ackman was engaged to Neri Oxman, an Israeli-American architect, designer, and professor at the MIT Media Lab. She's known for her work in computational design, biology, and materials science.[18] They married in January 2019. The wedding coverage played up how they brought together finance and scientific research.[19]

Ackman is Jewish and active in Jewish communal causes, especially around Israel.[20]

Philanthropy

Ackman and his wife co-founded the Pershing Square Foundation, supporting various philanthropic efforts.[4] He signed onto The Giving Pledge, the commitment started by Warren Buffett and Bill Gates that gets billionaires to commit to giving away most of their wealth in their lifetime or through their wills.[21] According to The Chronicle of Philanthropy, he's ranked among America's top philanthropists by donation size.[22]

The foundation has put money toward education, health, economic development, and human rights. His giving has focused on New York City and fighting poverty.

Recognition

Ackman's been everywhere in the media. Investment campaigns, feuds with other investors, constant commentary. He shows up regularly on CNBC, Bloomberg News, and in The New York Times.[23]

Christine S. Richard wrote Confidence Game: How a Hedge Fund Manager Called Wall Street's Bluff, which covered one of Ackman's major campaigns and detailed how he works and how relentlessly he pursues an investment thesis.[24]

His Pershing Square returns have put him in the top tier of hedge fund managers in certain years, earning industry recognition.[2] What sets him apart is his knack for getting attention for his investment ideas through presentations, media appearances, and X posts.

Legacy

Ackman's career mixes concentrated, high-conviction investing with a willingness to go public and push for change at companies he owns. His activist model—large stakes, detailed public theses, pushing for management or strategic shifts—helped shape how activist hedge funds work today.

His wins and losses have been unusually visible. The Herbalife short, the Valeant disaster, J.C. Penney, Canadian Pacific Railway turnaround. Business schools study them. Investors study them. Financial journalists study them.

His profile has grown way beyond finance in recent years. He's vocal on antisemitism, higher education, immigration. He's become polarizing in American public debate. His shift from Democratic donor to Trump supporter mirrors broader changes in parts of the business world.

Through Pershing Square Foundation and The Giving Pledge, he's tried to direct his wealth toward good causes, though his public controversies have sometimes overshadowed those efforts.

References

  1. ↑ 1.0 1.1 1.2 "Pershing Square Holdings". 'Pershing Square Holdings}'. Retrieved 2026-02-23.
  2. ↑ 2.0 2.1 2.2 2.3 "Ackman's returns make him a top 20 fund manager". 'CNBC}'. 2015-01-26. Retrieved 2026-02-23.
  3. ↑ 3.0 3.1 "Bill Ackman reveals stake in Meta, says it has 'deeply discounted valuation'".CNBC.2026-02-11.https://www.cnbc.com/2026/02/11/bill-ackman-meta-valuation.html.Retrieved 2026-02-23.
  4. ↑ 4.0 4.1 "Our Founders". 'Pershing Square Foundation}'. Retrieved 2026-02-23.
  5. ↑ "Miss Ronnie I. Posner Bride of L.D. Ackman".The New York Times.1963-10-07.https://www.nytimes.com/1963/10/07/archives/miss-ronnie-i-posner-bride-of-ld-ackman.html.Retrieved 2026-02-23.
  6. ↑ "Bio: Bill Ackman". 'Harvard Law School Program on Corporate Governance}'. Retrieved 2026-02-23.
  7. ↑ "The Rookies' Big Score".The Washington Post.1994-07-10.https://www.washingtonpost.com/archive/business/1994/07/10/the-rookies-big-score/2e22cacf-a4e4-445c-a077-19518bcddbf9/.Retrieved 2026-02-23.
  8. ↑ "Ackman quits J.C. Penney board, removing distraction".Reuters.2013-08-13.https://www.reuters.com/article/us-jcpenney-ackman/ackman-quits-j-c-penney-board-removing-distraction-idUSBRE97C0AI20130813.Retrieved 2026-02-23.
  9. ↑ "Bill Ackman Is Done Losing Money on Valeant". 'Bloomberg}'. 2017-03-14. Retrieved 2026-02-23.
  10. ↑ "Bill Ackman makes bold AI bet".TheStreet.2026-02-20.https://www.thestreet.com/investing/bill-ackman-makes-bold-ai-bet.Retrieved 2026-02-23.
  11. ↑ "A Billionaire Just Bet Big on This AI Stock. Should Investors Follow Suit?".The Motley Fool.2026-02-22.https://www.fool.com/investing/2026/02/22/a-billionaire-just-bet-big-on-this-ai-stock-should/.Retrieved 2026-02-23.
  12. ↑ "AI security startup Outtake raises $40M from Iconiq, Satya Nadella, Bill Ackman, and other big names".TechCrunch.2026-01-28.https://techcrunch.com/2026/01/28/ai-security-startup-outtake-raises-40m-from-iconiq-satya-nadella-bill-ackman-and-other-big-names/.Retrieved 2026-02-23.
  13. ↑ "'This is a mistake President': Bill Ackman responds to Trump's call for a one-year 10% cap on credit card interest".Business Insider.2026-01.https://www.businessinsider.com/ackman-trump-call-cap-credit-card-interest-mistake-affordability-2026-1.Retrieved 2026-02-23.
  14. ↑ RoeloffsMaryMary"Billionaire Ackman Donates To Support ICE Agent Who Shot Renee Good".Forbes.2026-01-12.https://www.forbes.com/sites/maryroeloffs/2026/01/12/billionaire-bill-ackman-gives-10000-to-support-ice-agent-in-minneapolis-shooting/.Retrieved 2026-02-23.
  15. ↑ "Billionaire Bill Ackman defends controversial $10K donation to ICE agent who fatally shot Renee Nicole Good".New York Post.2026-01-13.https://nypost.com/2026/01/13/us-news/billionaire-bill-ackman-defends-controversial-10k-donation-to-ice-agent-who-fatally-shot-renee-nicole-good/.Retrieved 2026-02-23.
  16. ↑ "Bernie Sanders Blasts Elon Musk, Bill Ackman And Peter Thiel, Demands Billionaires Cough Up Their 'Fair Share' Of Taxes".Yahoo News.2026-02-21.https://www.yahoo.com/news/articles/bernie-sanders-blasts-elon-musk-023020754.html.Retrieved 2026-02-23.
  17. ↑ "Weddings; Karen Herskovitz, William Ackman".The New York Times.1994-07-10.https://www.nytimes.com/1994/07/10/style/weddings-karen-herskovitz-william-ackman.html.Retrieved 2026-02-23.
  18. ↑ "Activist investor Bill Ackman is engaged to rockstar scientist Neri Oxman".Fast Company.2018.https://www.fastcompany.com/90249034/activist-investor-bill-ackman-is-engaged-to-rockstar-scientist-neri-oxman.Retrieved 2026-02-23.
  19. ↑ "As if by Design, Their Connection Was Inevitable".The New York Times.2019-01-19.https://www.nytimes.com/2019/01/19/fashion/weddings/as-if-by-design-their-connection-was-inevitable.html.Retrieved 2026-02-23.
  20. ↑ "The Fighter: Bill Ackman". 'Jewish Business News}'. 2013-02-03. Retrieved 2026-02-23.
  21. ↑ "Jewish Billionaires Join Group Pledging Majority of Their Wealth to Charity". 'Jewish Voice}'. Retrieved 2026-02-23.
  22. ↑ "Philanthropy 50". 'The Chronicle of Philanthropy}'. Retrieved 2026-02-23.
  23. ↑ "Bill Ackman CNBC Interview". 'CNBC}'. Retrieved 2026-02-23.
  24. ↑ "Confidence Game: How Hedge Fund Manager Bill Ackman Called Wall Street's Bluff". 'Amazon}'. Retrieved 2026-02-23.
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