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Bill Ackman

Bill Ackman is an American billionaire hedge fund manager and activist investor.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 27, 2026|2 min read| Fact-checked

Bill Ackman is an American billionaire hedge fund manager and activist investor. He is the founder and chief executive of Pershing Square Capital Management, a concentrated investment firm known for high-conviction public-market bets and shareholder campaigns. Ackman is relevant to Canadian readers because Pershing Square has been associated with major Canadian investments and activism, including Canadian Pacific Railway.

Early life and education

William Albert Ackman was born on May 11, 1966, in Chappaqua, New York, and later attended Harvard University. His background and education helped position him for a career in finance and investing.

Pershing Square Capital Management

Ackman founded Pershing Square in 2004 and is its CEO. The firm is known for a concentrated investment approach and for working actively with portfolio companies.

Investment approach

Ackman is known for activist, high-conviction investing, often taking large stakes in a small number of companies. Pershing Square describes its strategy as investing in high-quality, simple, predictable, cash-generative businesses.

Public profile and controversies

Ackman became a prominent public figure through shareholder activism and later through high-profile social media commentary. He also attracted attention for criticism of Harvard and other institutions in 2023 and 2024.

Net worth and recognition

Ackman’s wealth has fluctuated with the performance of his investments and fund structure, with Bloomberg estimating his net worth at about US$8 billion in April 2026. Fortune and other outlets continue to rank him among the most influential figures in finance.

Key facts

  • Bill Ackman is an American billionaire hedge fund manager and activist investor.
  • He founded and leads Pershing Square Capital Management, known for concentrated, high-conviction investing.
  • Ackman gained prominence through activist campaigns involving companies like Herbalife, Chipotle, and Canadian Pacific Railway.
  • Bloomberg estimated his net worth at about US$8 billion in April 2026.
  • He has drawn attention for public commentary on politics, universities, and social issues.
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Canadian context

Ackman is relevant to Canadian readers because Pershing Square has been associated with major Canadian investments and activism, including Canadian Pacific Railway.[8][12]

Frequently asked questions

Who is Bill Ackman?
Bill Ackman is an American billionaire hedge fund manager and activist investor. He is the founder and CEO of Pershing Square Capital Management.
What is Bill Ackman's net worth?
Bloomberg estimated Bill Ackman’s net worth at about US$8 billion in April 2026. Other estimates vary by source and date.
What company does Bill Ackman run?
He runs Pershing Square Capital Management, the investment firm he founded in 2004.
What is Bill Ackman's investment strategy?
His approach is activist and concentrated: Pershing Square takes large stakes in a small number of public companies and seeks long-term value creation through active engagement.
Why is Bill Ackman famous?
He is famous for high-profile activist investments, major public campaigns around companies and institutions, and his strong presence in business and political commentary.

References

  1. Wikipedia — https://en.wikipedia.org/wiki/Bill_Ackman
    Supports: Basic biographical details, founding of Pershing Square, activist investor description, and Bloomberg net worth estimate.
  2. Encyclopaedia Britannica — https://www.britannica.com/money/Bill-Ackman
    Supports: Biography, role as founder and CEO of Pershing Square, activist investor profile, and public prominence.
  3. Pershing Square Philanthropies — https://pershingsquarephilanthropies.org/people/bill-ackman
    Supports: Ackman as CEO of Pershing Square, founding year, concentrated investment approach, and active engagement with portfolio companies.
  4. Fortune — https://fortune.com/ranking/most-powerful-people/2025/bill-ackman/
    Supports: Pershing Square assets, activist reputation, prominent influence, and Canadian Pacific Railway as a notable investment.
  5. CNBC — https://www.cnbc.com/bill-ackman/
    Supports: Founding of Pershing Square and notoriety for activist initiatives involving companies such as General Growth Properties and Herbalife.
  6. Bloomberg — https://www.bloomberg.com/features/2025-bill-ackman-tweeting-through-it/
    Supports: Description of Ackman as an activist investor and context for his public profile.
  7. Vox — https://www.vox.com/2024/1/13/24032176/bill-ackman-claudine-gay-harvard-plagiarism-business-insider-explained
    Supports: General background on his public attention, activist investing reputation, and examples of companies involved in his investing history.