Challenges Faced by Bill Ackman: Obstacles and Turning Points

By Popular Timelines Editorial Team · Updated: July 19, 2026

Resilience and perseverance in the journey of Bill Ackman. A timeline of obstacles and growth.

Bill Ackman is a prominent American billionaire investor and the founder and CEO of Pershing Square Capital Management. He is widely recognized for his activist investing style, where he takes significant stakes in companies to advocate for operational or management changes to unlock shareholder value. Throughout his career, Ackman has been involved in several high-profile financial campaigns, including his notable short position against Herbalife and his successful long-term investment in Canadian Pacific Railway. Beyond his investment firm, Ackman is known for his public commentary on economic policy, corporate governance, and various social issues, frequently utilizing social media to influence discourse. His investment strategy often involves concentrated portfolios and deep research, making him one of the most influential figures on Wall Street. Despite periods of volatility in his fund's performance, he remains a key figure in modern finance and a vocal advocate for his investment theses.

Sections (5)

Full Timeline Early Life & Education Career & Achievements Challenges & Struggles Controversies & Scandals

1995: Bid for Rockefeller Center

In 1995, Bill Ackman partnered with Leucadia National to place a bid on Rockefeller Center; while unsuccessful, the effort raised the profile of Gotham Partners and helped grow their assets under management significantly.

2002: Gotham Partners Litigation

By 2002, the investment firm Gotham Partners became heavily involved in legal conflicts and litigation with other shareholders who shared interests in the firm's portfolio companies.

2002: Challenge to MBIA Credit Rating

In 2002, Bill Ackman conducted extensive research into MBIA to contest the AAA bond rating provided by Standard & Poor's. During this process, his legal team incurred over $100,000 in costs to process 725,000 pages of financial documents under subpoena, and Ackman publicly advocated for the structural separation of MBIA's municipal bond and structured finance divisions.

2003: Feud with Carl Icahn

In 2003, a significant financial disagreement emerged between Bill Ackman and investor Carl Icahn regarding an investment deal, leading Ackman to initiate a lawsuit against Icahn to recover his portion of profits from a specific stock sale.

2008: Shorting MBIA Bonds

During the 2008 financial crisis, Bill Ackman engaged in a notable market maneuver by shorting the bonds of MBIA, a financial services company.

2012: Initiation of Herbalife Short Position

In 2012, Bill Ackman began a high-profile one billion dollar short position against Herbalife, publicly denouncing the organization as a pyramid scheme.

August 2013: Ackman Resigns from J. C. Penney Board

In August 2013, Bill Ackman ended his two-year campaign to restructure J. C. Penney by resigning from the company's board of directors following internal conflicts with other board members.

April 2014: FBI Investigation into Herbalife

In April 2014, it was reported by Reuters that the FBI had initiated an investigation into Herbalife, which involved the review of documents gathered from the company's former distributors.

March 12, 2015: Probe into Pershing Square Tactics

On March 12, 2015, reports surfaced that federal authorities and the FBI were investigating whether individuals hired by Bill Ackman provided false information to regulators in an attempt to manipulate Herbalife's stock price.

2015: Start of Period of Weak Performance

Starting in 2015, Bill Ackman's firm, Pershing Square, entered a challenging period characterized by weak financial returns.

March 2017: Divestment of Valeant Pharmaceuticals Shares

In March 2017, Bill Ackman sold his final 27.2 million shares of Valeant Pharmaceuticals for approximately $300 million, resulting in a significant financial loss for his firm.

August 2017: Acquisition and Proxy Fight for ADP

In August 2017, Bill Ackman purchased an 8% stake in Automatic Data Processing (ADP) and initiated a proxy battle to secure three seats on the company's board of directors.

November 2017: Adjustment of Herbalife Short-Sell Position

In November 2017, Bill Ackman announced that he had covered his primary short-sell position regarding Herbalife, though he clarified his intention to maintain bearish exposure through the use of put options.

February 28, 2018: Full Exit from Herbalife Short Position

On February 28, 2018, Bill Ackman officially closed out his long-standing, near-billion-dollar short position against the company Herbalife, resulting in a financial loss.

2018: Conclusion of Financial Underperformance

By 2018, the firm's period of weak market performance came to an end, prompting Ackman to restructure the management of Pershing Square.

2019: Exit from ADP Investment

After losing the proxy fight that lasted three months, Bill Ackman concluded his investment in Automatic Data Processing by selling his remaining shares in 2019.

August 1, 2024: Withdrawal of Pershing Square USA IPO

On August 1, 2024, Bill Ackman officially withdrew the initial public offering for his new fund, Pershing Square USA, after failing to secure more than $2 billion in capital, and subsequently signaled his intent to pursue a revised transaction structure for a future launch.