With a net worth of $9.3 billion, Bill Ackman is more than a one-percenter -- he's No. 311 on Forbes' List of Billionaires. The billionaire hedge fund manager is an activist investor through Pershing Square Capital Management, the company he founded and runs.
Activist investors buy large interests in underperforming companies and use their influence as major shareholders to pressure company leaders into managing the business differently. This article will explore Ackman's success and investing philosophy. Keep reading to learn all about him.
Primary role
- Founder, Pershing Square Capital Management
- Former founder, Gotham Partners
Investment strategy
Bill Ackman is a famous investor primarily known as an activist investor, meaning he scoops up large shares in companies that are often undervalued or mismanaged and uses his influence to increase shareholder value and the company's stock price.
Ackman's first big win was a position he opened with Gotham Partners. In 2002, Gotham bet on the failure of municipal bond insurer MBIA with a leveraged short position and credit default swaps (CDS). Gotham also published a report arguing that MBIA did not deserve its AAA credit rating, prompting a probe by the U.S. Securities and Exchange Commission (SEC).
Ackman's doomsday prediction for MBIA focused on the company's exposure to subprime mortgage-backed securities. Although his warnings were largely ignored, he continued his crusade against MBIA for six years while growing his investment in the company's failure.
Philosophy & legacy
As an activist investor, Ackman's primary driving philosophy centers on the idea that some companies are simply poorly managed or undervalued, and by making large investments in these companies, he can influence them and help turn them around. Although he primarily takes long positions, he has also made a lot of money on shorts, including the short of MBIA, which he was convinced was not being properly rated.
Investing is a business where you can look very silly for a long period of time before you are proven right.
He hasn't published any books, but he has been very active on social media, especially X, where he has influenced millions of followers. Although no prominent investors have outright claimed that his influence has affected their investment decisions, his approach to activist investing has influenced many companies and how they conduct business.
He has also recently been using his social media clout to push for the dissolution of diversity, equity, and inclusion (DEI) programs and to support other conservative talking points and candidates.
Awards, honors, & recognition
2025 -- University of Haifa Honorary Doctorate
2025 -- Patriot Award from the Navy SEAL Foundation
2025 -- Rang the bell at the Tel Aviv Stock Exchange
Related investing topics
Personal notes
In conjunction with the Columbia Business School, Ackman and Pershing Square launched the Pershing Square Value Investing and Philanthropy Challenge in 2008.
This challenge provides students with hands-on experience in selecting, researching, and pitching investment ideas. Students are then judged on the quality of both ideas and research, as well as the pitch delivery, by the same standards an investment committee would hold them to if it were a real-life pitch.
Pershing Square Philanthropies also awards two annual prizes in life sciences:
- The Pershing Square Sohn Cancer Prize: designed to support and establish a pipeline for early-stage biomedical investments that contribute to the fight against cancer
- The MIND (Maximizing Innovation in Neuroscience Discovery) Prize: seeks groundbreaking research ideas for neurodegenerative diseases
Each prize awards $250,000 per year for three years, for a total of $750,000.
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