Bill Ackman

Bill Ackman
Born	William Albert Ackman 11 5, 1966
Birthplace	Chappaqua, New York, U.S.
Nationality	American
Occupation	Hedge fund manager
Title	CEO of Pershing Square Capital Management
Known for	Founder and CEO of Pershing Square Capital Management
Education	Harvard University (BA, MBA)
Spouse(s)	Karen Herskovitz (m. 1994; div.) Neri Oxman (m. 2019)
Website	[https://www.pershingsquareholdings.com/ Official site]

William Albert Ackman (born May 11, 1966), known as Bill Ackman, is an American billionaire hedge fund manager, investor, and philanthropist. He is the founder and chief executive officer of Pershing Square Capital Management, a hedge fund and investment management firm based in New York City. Over the course of a career spanning more than three decades, Ackman has become one of the most prominent figures on Wall Street, known for his activist investment strategies, large concentrated bets on public companies, and willingness to engage in high-profile public disputes over corporate governance and valuation. His investment career has been marked by both spectacular successes—including profitable positions in companies such as Canadian Pacific Railway and Chipotle Mexican Grill—and costly failures, most notably a protracted short position against Herbalife and a significant loss on Valeant Pharmaceuticals. Beyond finance, Ackman has drawn attention for his philanthropy, his outspoken commentary on social and political issues, and his increasing engagement in national politics. In recent years, he has taken prominent public positions on university campus culture, support for Israel, and American fiscal policy, becoming a frequent voice on social media and in national news coverage.

Early Life

William Albert Ackman was born on May 11, 1966, in Chappaqua, New York, an affluent hamlet in Westchester County. His father, Lawrence D. Ackman, was the chairman of a New York real estate financing firm, Ackman-Ziff Real Estate Group. The elder Ackman had married Ronnie I. Posner in 1963. Growing up in a family deeply connected to the real estate industry, Ackman was exposed from an early age to the dynamics of deal-making, financial analysis, and property markets. His upbringing in the prosperous suburbs of New York provided him with both the educational opportunities and the social networks that would later prove instrumental in his career in finance.

Ackman has described himself as having been competitive and intellectually ambitious from a young age. He attended local schools in the Chappaqua area before pursuing higher education at Harvard University. His family background in Jewish-American life has remained a visible aspect of his public identity, and he has spoken publicly about his Jewish heritage on numerous occasions, particularly in the context of his philanthropic work and, more recently, his commentary on antisemitism and support for Israel.

Education

Ackman attended Harvard University, where he earned a Bachelor of Arts degree. He subsequently returned to Harvard to attend Harvard Business School, where he received his Master of Business Administration degree. His time at Harvard proved formative, exposing him to both rigorous academic training in finance and economics and a network of future business leaders and investors. Ackman has frequently credited his education at Harvard with shaping his analytical approach to investing and his belief in the power of deep fundamental research.

Career

Early Career and Gotham Partners

After completing his MBA at Harvard Business School, Ackman co-founded Gotham Partners Management in 1992 with a fellow Harvard Business School graduate. The firm focused on investments in both public and private markets, with a particular emphasis on real estate and special situations. Gotham Partners attracted early attention for its aggressive investment style and its willingness to take concentrated positions.

In 1994, The Washington Post profiled Ackman as part of a new generation of aggressive young investors in New York, highlighting his early successes and ambitious approach to the markets. However, Gotham Partners ultimately encountered difficulties. The firm became embroiled in disputes related to some of its investments, and it was eventually wound down in the early 2000s. The experience, while humbling, provided Ackman with lessons that would shape his subsequent approach to portfolio management, concentration risk, and public communication.

Founding of Pershing Square Capital Management

In 2004, Ackman founded Pershing Square Capital Management, which would become his primary investment vehicle and one of the most closely watched hedge funds in the world. Named after Pershing Square, a small park in Manhattan adjacent to Grand Central Terminal, the firm adopted a concentrated, activist approach to investing. Ackman's strategy centered on identifying large-cap companies that he believed were undervalued or poorly managed, taking significant equity stakes, and then working to effect changes—ranging from management overhauls to strategic restructurings—that he believed would unlock shareholder value.

Pershing Square grew rapidly, and Ackman's concentrated, high-conviction bets made headlines across the financial world. By 2015, his returns had earned him recognition as one of the top 20 fund managers in the hedge fund industry. The firm managed billions of dollars in assets and attracted institutional investors, pension funds, and high-net-worth individuals.

Pershing Square also launched a publicly listed closed-end fund, Pershing Square Holdings, which trades on the Euronext Amsterdam stock exchange, giving a broader range of investors access to Ackman's portfolio.

Notable Investments

Ackman's career at Pershing Square has been defined by a series of large, highly publicized investments, some extraordinarily profitable and others resulting in significant losses.

One of his most successful campaigns was his investment in Canadian Pacific Railway, in which Pershing Square took a major stake and pushed for management changes. The campaign resulted in a significant increase in the company's stock price and is frequently cited as one of the most successful activist campaigns in modern hedge fund history.

Ackman also held a major position in Chipotle Mexican Grill, which proved profitable as the restaurant chain recovered from a series of food safety crises and implemented operational changes.

However, Ackman's investment in Valeant Pharmaceuticals became one of the most high-profile losses of his career. Pershing Square built a large position in the pharmaceutical company, which came under intense scrutiny for its aggressive drug pricing practices and accounting concerns. As Valeant's stock plummeted, Ackman was forced to exit the position at a substantial loss. In a 2017 analysis, Bloomberg noted that Ackman was "done losing money on Valeant," marking the end of a painful chapter for his fund.

Another widely followed saga was Ackman's multi-year short bet against Herbalife, a nutritional products company that he publicly accused of operating as a pyramid scheme. The bet pitted him against other prominent investors, most notably Carl Icahn, who took the opposite side of the trade. The Herbalife short became one of the most public and contentious battles in Wall Street history. Ackman eventually closed his short position without the definitive regulatory action he had sought, though the Federal Trade Commission did require Herbalife to make significant changes to its business practices.

Ackman's involvement with J.C. Penney was another notable episode. He joined the retailer's board of directors and pushed for a dramatic transformation of the company's business model. The overhaul, however, alienated customers and led to declining sales. In August 2013, Ackman resigned from the J.C. Penney board, citing a desire to remove what he described as a "distraction" for the company.

Recent Investment Activity

In early 2026, Ackman continued to attract significant attention for his investment decisions. During Pershing Square's annual investor presentation in February 2026, Ackman revealed a new stake in Meta Platforms, the parent company of Facebook, Instagram, and WhatsApp. He described the social media and technology conglomerate as having a "deeply discounted valuation" and articulated a thesis centered on the company's growth prospects, particularly in artificial intelligence. The investment drew widespread commentary, with analysts and financial media examining whether other investors should follow Ackman's lead into the stock.

Pershing Square's most recent 13F filings indicated that Ackman had continued to make significant allocations toward companies with substantial artificial intelligence exposure, reflecting a broader strategic shift within the fund toward technology and AI-driven growth.

Beyond his public market portfolio, Ackman has also invested in private technology companies. In January 2026, he participated in a $40 million funding round for Outtake, an AI security startup, alongside investors including Satya Nadella and Iconiq Capital.

Public Commentary on Economic Policy

Ackman has not limited his public commentary to corporate governance and investment theses. He has increasingly weighed in on broader economic and fiscal policy matters. In January 2026, when President Trump called for a one-year 10% cap on credit card interest rates, Ackman publicly criticized the proposal, calling it a "mistake" and arguing that it could have negative consequences for consumer credit markets and affordability. The episode underscored Ackman's willingness to publicly challenge even those political figures with whom he has otherwise been aligned.

Personal Life

In 1994, Ackman married Karen Ann Herskovitz, a landscape designer. The couple later divorced.

In 2018, it was reported that Ackman was engaged to Neri Oxman, an Israeli-American architect, designer, and professor at the MIT Media Lab, known for her pioneering work at the intersection of computational design, biology, and materials science. The couple married in January 2019 in a ceremony that was profiled in The New York Times, which described their connection as having been "as if by design."

Ackman has spoken publicly about his Jewish heritage and has been active in Jewish communal and philanthropic life. He has been an outspoken supporter of Israel, particularly following the October 7, 2023 attacks, during which he criticized pro-Palestinian protests on university campuses and called attention to what he described as rising antisemitism in American higher education.

A long-time donor to Democratic candidates and organizations, Ackman shifted his political alignment in the 2024 election cycle, endorsing Donald Trump in the 2024 United States presidential election. The endorsement drew significant media attention given Ackman's history of Democratic donations and his increasing prominence as a conservative-leaning public commentator on social media.

In early 2026, Ackman made headlines for donating $10,000 to a GoFundMe campaign supporting an ICE agent involved in a controversial shooting in Minneapolis, and subsequently defended the donation publicly.

Ackman's wealth and political visibility have also made him a target of political criticism. In February 2026, Senator Bernie Sanders publicly named Ackman alongside Elon Musk and Peter Thiel in a call for billionaires to pay their "fair share" of taxes, using the debate over a proposed California wealth tax as a platform for his argument.

Philanthropy

Ackman and his family have been active philanthropists. He is a co-founder of the Pershing Square Foundation, which supports a range of charitable causes including education, health, social justice, and entrepreneurship. Ackman has appeared on the Chronicle of Philanthropy's Philanthropy 50 list, which ranks the largest individual charitable donors in the United States.

He has also signed The Giving Pledge, an initiative created by Warren Buffett and Bill Gates that encourages the world's wealthiest individuals to commit the majority of their wealth to philanthropy, either during their lifetimes or in their wills.

The Pershing Square Foundation has funded initiatives across several continents, with a particular focus on supporting innovative approaches to social problems, academic research, and public health.

Recognition

Ackman has been the subject of extensive media coverage throughout his career. His investment campaigns, public battles with other investors and corporate executives, and increasingly prominent political commentary have made him one of the most recognizable figures in the hedge fund industry.

His battle with Herbalife was documented in Christine Richard's book Confidence Game: How a Hedge Fund Manager Called Wall Street's Bluff, which detailed the research and strategy behind his most prominent short-selling campaigns.

Ackman has been a frequent guest on financial news programs, particularly on CNBC, where he has participated in extended interviews about his investment theses, market outlook, and public policy views. His public statements and social media posts regularly generate substantial coverage in outlets including The New York Times, The Wall Street Journal, Bloomberg, Forbes, and Business Insider.

His ranking among the top 20 hedge fund managers by returns, as recognized by CNBC in 2015, placed him alongside some of the most prominent names in the history of the industry.

Legacy

Bill Ackman's career represents one of the most documented case studies in modern activist investing. His approach—taking large, concentrated positions in public companies and then aggressively campaigning for change—has influenced a generation of hedge fund managers and reshaped the relationship between institutional investors and corporate boards. Whether through successful campaigns like Canadian Pacific Railway or controversial ones like Herbalife and J.C. Penney, Ackman has consistently demonstrated a willingness to stake his reputation and his capital on his convictions.

His transition from a primarily financial figure to one who is also prominent in political and cultural discourse has mirrored broader trends among American billionaires in the 2020s. His public commentaries on higher education, antisemitism, immigration, and fiscal policy have extended his influence well beyond the world of finance, though they have also generated significant controversy and criticism.

Through the Pershing Square Foundation and The Giving Pledge, Ackman has committed to directing a substantial portion of his wealth to charitable causes, positioning himself within a tradition of Wall Street philanthropists who seek to leverage their financial success for broader social impact.

As of early 2026, Ackman remains an active investor, continuing to deploy capital into both public equity markets—with a particular focus on technology and artificial intelligence—and private ventures. His career continues to evolve, and his influence on both financial markets and American public life shows no signs of diminishing.