Career Timeline of Bill Ackman: Major Achievements and Milestones

How Bill Ackman built a successful career. Explore key moments that defined the journey.

Bill Ackman is an American billionaire hedge fund manager, the founder, and CEO of Pershing Square Capital Management. Known as an activist investor, Ackman's strategies often involve taking significant stakes in companies and then publicly advocating for changes in their management or business strategies. As of July 2025, his estimated net worth is $9.4 billion, highlighting his success and influence in the financial world.

Sections (5)

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

1992: Founding of Gotham Partners

In 1992, Bill Ackman co-founded the investment firm Gotham Partners with David P. Berkowitz. The firm focused on small investments in public companies.

1995: Partnership with Leucadia National to Bid for Rockefeller Center

In 1995, Bill Ackman partnered with Leucadia National, an insurance and real estate firm, to bid for Rockefeller Center.

2002: Research into MBIA

In 2002, Bill Ackman researched MBIA to challenge Standard & Poor's AAA rating of its bonds. His law firm copied 725,000 pages of statements at a cost of over $100,000. He also called for a division between MBIA's structured finance and municipal bond insurance businesses.

2004: Launch of Pershing Square Capital Management

Bill Ackman launched Pershing Square Capital Management in 2004.

2006: Pershing Square Foundation Founded

In 2006, Bill Ackman and his then wife Karen founded the Pershing Square Foundation to fund innovative organizations focused on various areas such as economic development, education, and human rights.

2008: Profit from MBIA Credit Default Swaps

In 2008, Ackman profited from credit default swaps against MBIA corporate debt during the financial crisis.

2008: Shorting MBIA Bonds

One of Bill Ackman's most notable market plays was shorting MBIA's bonds during the 2008 financial crisis.

January 16, 2009: Covering Short Position on MBIA

On January 16, 2009, Bill Ackman reported covering his short position on MBIA, according to a 13D filing with the SEC.

2010: Chairman of Howard Hughes Holdings

From 2010 until 2024, Bill Ackman was chairman of Howard Hughes Holdings.

2010: Investment in J. C. Penney

In 2010, Pershing Square started buying J. C. Penney shares, paying an average of $22 for 39 million shares, representing 18% of the company's stock.

2011: Ackmans listed on Philanthropy 50

In 2011, Bill and Karen Ackman were listed on The Chronicle of Philanthropy's "Philanthropy 50" list of the most generous donors.

2011: Icahn Pays Ackman in Lawsuit Settlement

In 2011, Carl Icahn was forced to pay Bill Ackman $4.5 million plus 10% interest per year and legal fees, totaling $9 million, as a result of the lawsuit over the investment deal.

2011: Acquisition of Canadian Pacific Railway Shares

In 2011, Pershing Square began acquiring shares of Canadian Pacific Railway, eventually becoming the railway's largest shareholder.

May 2012: Proxy Contest Victory at Canadian Pacific Railway

In May 2012, nearly 90% of shareholder votes supported Ackman's dissident slate at Canadian Pacific Railway's annual meeting, leading to the replacement of much of the company's leadership.

December 2012: Short Bet Against Herbalife

In December 2012, Bill Ackman announced that Pershing Square had made a $1 billion short bet against Herbalife, a maker of weight-loss and vitamin supplements, and described the company as a "pyramid scheme".

2012: Shorting Herbalife

From 2012 to 2018, Bill Ackman held a US$1 billion short against Herbalife, describing the company as a pyramid scheme.

January 2013: Icahn's Stake in Herbalife

In January 2013, Carl Icahn announced a stake in Herbalife to combat Ackman's short position, following a dispute between the two on CNBC.

August 2013: Ackman Steps Down from J. C. Penney Board

In August 2013, Bill Ackman stepped down from the board of J. C. Penney following a disagreement with fellow board members, ending a two-year campaign to transform the department store.

2014: Pershing Square's Net Gains

In 2014, Pershing Square delivered $4.5 billion in net gains for investors.

2015: Weak Performance

Bill Ackman's Pershing Square had a weak performance in 2015–2018.

April 27, 2016: Testimony Before Senate Committee on Aging

On April 27, 2016, Bill Ackman testified before the United States Senate Special Committee on Aging with Valeant Pharmaceuticals' outgoing CEO, J. Michael Pearson, and former interim CEO, Howard Schiller, regarding concerns about Valeant's business model and pricing practices.

2016: Investment in Chipotle Mexican Grill

In 2016, Bill Ackman began investing in Chipotle Mexican Grill.

2016: Endorsement and Vote in 2016 Presidential Election

In 2016, Bill Ackman endorsed Michael Bloomberg as a prospective candidate for President of the United States and voted for Donald Trump in the election.

March 2017: Sale of Valeant Shares

In March 2017, Bill Ackman sold his remaining 27.2 million share position in Valeant for approximately $300 million, resulting in a substantial loss.

November 2017: Ackman Covers Short-Sell Position in Herbalife

In November 2017, Bill Ackman said that he had covered his short-sell position in Herbalife, but would continue to bet against Herbalife using put options.

2017: Chipotle Among Top Holdings

From 2017 to 2024, Chipotle Mexican Grill was among Pershing Square's top holdings.

February 28, 2018: Ackman Exits Herbalife Bet at a Loss

On February 28, 2018, Bill Ackman exited his near billion-dollar bet against Herbalife at a loss.

2018: Weak Performance

Bill Ackman's Pershing Square had a weak performance in 2015–2018.

2018: Shorting Herbalife

From 2012 to 2018, Bill Ackman held a US$1 billion short against Herbalife, describing the company as a pyramid scheme.

2018: Hiring of Brian Niccol as CEO of Chipotle

In 2018, Bill Ackman was credited with helping Chipotle Mexican Grill rebound from years of losses by playing a part in hiring Brian Niccol as CEO.

2019: Pershing Square's Strong Performance

In 2019, Pershing Square returned 58.1%, qualifying it as one of the world's best performing hedge funds for the year.

March 3, 2020: Disclosure of Pershing Square's Portfolio Hedge

On March 3, 2020, Pershing Square first disclosed that it had hedged its portfolio, investing $27 million to purchase credit protection against steep market losses.

March 18, 2020: Ackman Calls for Economic Shutdown

On March 18, 2020, Bill Ackman called upon President Donald Trump for a "30-day shutdown" of the American economy to slow the spread of coronavirus and minimize loss of life and ensuing economic destruction. He also cautioned U.S. companies to stop stock buyback programs because "hell is coming".

March 15, 2021: Donation of Coupang Shares

On March 15, 2021, Bill Ackman announced that he donated 26.5 million shares (valued at $1.36 billion) in American e-commerce company Coupang to three entities, including his own foundation.

2021: Ackman listed on Philanthropy 50 with Neri Oxman

In 2021, Bill Ackman was listed on The Chronicle of Philanthropy's "Philanthropy 50" list again, this time with Neri Oxman.

2021: Pershing Square Acquires Stake in Universal Music Group

In 2021, Pershing Square acquired a 10 percent stake in Universal Music Group.

December 2022: Auctioned Lunch for Charity

In December 2022, Bill Ackman auctioned a lunch with himself for charity in partnership with the David Lynch Foundation, with proceeds going toward helping New York's frontline healthcare workers, police and veterans.

2022: Ackman Joins Universal Music Group Board

In 2022, Bill Ackman became a member of the board of directors of Universal Music Group.

February 2023: Funding for Sabatini's Research Laboratory

In February 2023, Bill Ackman announced that his foundation and an anonymous donor would together fund David M. Sabatini US$25 million over five years to establish and run a new research laboratory.

January 15, 2024: Phillips floats Cabinet post for Ackman and Musk

On January 15, 2024, Dean Phillips floated a possible Cabinet post for Bill Ackman and Elon Musk in a forum with them.

April 2024: Ackman Announces he will not support Joe Biden

In April 2024, Bill Ackman announced via X that he would not support Joe Biden in the upcoming election due to Biden's alleged lack of support for Israel.

July 14, 2024: Ackman Endorses Trump in 2024

On July 14, 2024, Bill Ackman endorsed Donald Trump in the aftermath of his attempted assassination.

August 1, 2024: Withdrawal of Pershing Square USA IPO

On August 1, 2024, after only securing $2 billion, Bill Ackman decided to withdraw the IPO for the new fund known as Pershing Square USA. He announced plans to relaunch a version of the fund with a new transaction structure.

2024: Stepping Down from Howard Hughes Holdings Board

Bill Ackman stepped down from the Howard Hughes Holdings board in 2024.

2024: Chipotle Among Top Holdings

From 2017 to 2024, Chipotle Mexican Grill was among Pershing Square's top holdings.

May 2025: Rejoins Howard Hughes Holdings Board as Executive Chairman

In May 2025, Bill Ackman rejoined the Howard Hughes Holdings board as Executive Chairman after Pershing Square increased its investment in the company to 47%.

July 2025: Ackman's Net Worth Estimated at $9.4 Billion

In July 2025, Forbes estimated Ackman's net worth to be $9.4 billion.

December 2025: Promotion of GoFundMe Page and Donation

Following the Bondi Beach shooting in December 2025, Bill Ackman promoted a GoFundMe page raising funds for Ahmed Al-Ahmed and later donated $99,999 to the campaign.

2025: UMG Stake as Largest Position

As of 2025, Pershing Square's 10% stake in Universal Music Group is one of the firm's largest positions.

2025: Involvement in NYC Mayoral Election

In 2025, Bill Ackman was a supporter of Andrew Cuomo during the New York City mayoral election and an outspoken critic of Zohran Mamdani, who later won the election.