William “Bill” Ackman is a political donor, pro-Israel activist, investor, and hedge fund manager at Pershing Square Capital Management. Ackman in known for shorting stocks, betting they would fall in value while pushing negative media stories about those companies. Ackman is also an “activist” investor who has pushed for policy and leadership changes at companies in which he owns stock. 1
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While Ackman has traditionally supported Democrats in the past, he has been a supporter of Israel and President Donald Trump’s second term. 1
Bill Ackman is CEO and portfolio manager at Pershing Square Capital Management (“Pershing Square”), a hedge fund firm he founded in 2003. 2 Previously, Ackman co-founded and managed the hedge fund firm Gotham Partners Management. 2 He began his career in real estate investment banking at Ackman Brothers and Singer Inc. 2 Ackman has a B.A. from Harvard College and an MBA from Harvard Business School. 2 In 2025, Forbes estimated Ackman to be worth $9.3 billion. 1
In 2005, Ackman and Pershing Square purchased a large share of Wendy’s stock and pressured management at the company to spin off its Tim Horton’s brand. 3 After Wendy’s agreed, Ackman sold his shares, making a large profit. The Wendy’s stock price later fell, 3 leading critics to claim that Ackman was responsible for leaving Wendy’s without the growing Tim Horton’s brand. 3
In 2008, Ackman and Pershing Square purchased a large share of Target Corporation and pressured the company to sell its credit card portfolio. 3
At the end of 2021, Pershing Square’s holdings were valued at $57 billion. 4 Pershing Square has made controversial investments and trades such as a short-sale of Herbalife in 2012. 4 (Short selling is a process by which one borrows shares for a set time to sell them, with the goal of repurchasing the shares to cover the loan at a lower price; short-sellers profit if the stock price of the company falls.) 5 Ackman and Pershing Square shorted about $1 billion of Herbalife stock, claiming the company operated as a pyramid scheme. 6 Ackman hired lobbyists attempting to convince Congress to investigate Herbalife, which resulted in Senator Ed Markey (D-MA) asking the Federal Trade Commission to investigate the company. 7 After five years and little change in stock price, Ackman’s Pershing Square dropped their short position in Herbalife. 8
In January 2022, Ackman and Pershing Square acquired 3.1 million shares of Netflix valued at $1.1 billion. 9 In April 2022, Ackman and the firm sold all the shares resulting in a $400 million loss in three months. 10
In 2022, Ackman announced that he planned to abandon high-profile investor activism. 11
As of September 2025, Ackman and Pershing Square oversaw some $30 billion in assets for pension funds, endowments and wealthy investors, invested in about a dozen companies. 11
In September 2025, VistaShares announced that it created an exchange-traded fund (ETF) that mirrored the publicly disclosed holdings of Ackman and Pershing Square. 11
In 2016, Bill Ackman wrote an op-ed supporting former New York City Mayor Michael Bloomberg (who did not run that year) over former Secretary of State Hillary Clinton for the Democratic nomination for President 12
In 2017, Ackman got into a heated exchange with then-former Vice President Joe Biden. 13 After a comment by Ackman that Biden took to be about his late son, Biden called Ackman an expletive and told him to “just shut the hell up.” 14 Ackman did not donate to Biden’s 2020 presidential election campaign. 15
In March 2020, Ackman called for President Donald Trump to shut down the country due to the coronavirus, stating that without lockdowns, “America will end as we know it.” 16 It is estimated that Pershing Capital made $3.8 billion on trades involving COVID-related market movements. 17
In 2021, Ackman angered some through a series of tweets supporting Kyle Rittenhouse during Rittenhouse’s homicide trial in Wisconsin. 18 Rittenhouse was later found not guilty on all counts. 19
In April 2025, Ackman warned of an “economic nuclear winter” over tariffs imposed by President Donald Trump. Ackman urged President Trump to pause the tariffs for 90 days. Ackman warned that Trump’s tariffs had threatened to undermine investor confidence in the U.S. He urged President Trump to negotiate with other countries and attract trillions in investment to the U.S. 20
In July 2025, Ackman donated $10 million to the International Tennis Hall of Fame after he participated in a widely mocked doubles match. Ackman claimed that his poor play had drawn lots of attention to the Hall of Fame. 21
In August 2025, Ackman proposed combining government-backed mortgage companies Fannie Mae and Freddie Mac, claiming that it would reduce mortgage rates and achieve huge synergies in their operations and the mortgage price. Ackman, who has held stakes in both companies for over a decade, also said that a merger would reduce regulatory costs since there would only be one company for the federal government to regulate. 22
In September 2025, Ackman said he was “very bullish” on Israel after a visit. He owns a five percent stake in the Tel Aviv Stock Exchange and he has an Israel-born wife. 23
Following attacks against Israel by the terror group Hamas on October 7, 2023, Ackman released a statement on X, formerly Twitter, calling for Harvard University to release the names of students who signed a letter blaming Israel for the attacks. 24 Ackman also criticized former Harvard president Claudia Gay for her congressional testimony in December 2023, which she gave along with Massachusetts Institute of Technology (MIT) president Sally Kornbluth and former University of Pennsylvania (UPENN) President Liz Magill, over the response to a rise in antisemitic incidents on college campuses following the October 7 attacks. 24 25 Ackman later called for Gay’s resignation after several sources, including The Washington Free Beacon and Harvard’s student paper, alleged evidence of plagiarism on several of Gay’s academic papers dating back to the 2000’s. Gay would step down from her position on January 2, 2024. 24 26
Ackman would go on to criticize diversity, equity, and inclusion (DEI) programs which Harvard and other universities promoted. The criticism drew weekly protests against Ackman by Al Sharpton. 27
In January 2024, a report by Business Insider claimed that Ackman’s wife, professor Neri Oxman, plagiarized her 2010 MIT dissertation by stealing, “sentences and whole paragraphs from Wikipedia” 24 as well as improperly quoting from other academic papers. 24 Oxman responded to the report on X, stating, “I regret and apologize for these errors,” 24 and argued she did not “place the subject language in quotation marks, which would be the proper approach for crediting the work.” 24 Ackman also responded on X by claiming the allegations by Business Insider against Oxman don’t “strike me as plagiarism,” 24 and further commented, “I am sure that when Neri wrote her dissertation she thought that there was nothing wrong with using Wikipedia as a dictionary.” 24 He later claimed that academic papers by Ivy League staff should be checked by Artificial Intelligence (AI) software to check for plagiarism. 24
In May 2025, Ackman supported the decision by the second Trump administration to withhold federal funds from Harvard University. Ackman also criticized Harvard’s investments claiming the school’s endowment was “poorly invested.” 28
In January 2024, Ackman donated $1 million to a super PAC supporting then-U.S. Rep. Dean Phillips’s (D-MN) primary challenge to then-President Joe Biden. He also called on President Biden to step aside and not seek reelection. 29
In April 2025, Ackman donated $250,000 to the Fix the City PAC which supported former New York Governor Andrew Cuomo for New York City mayor. 30
In June 2025, Ackman promised to fund a centrist candidate for New York City mayor after socialist Zohran Mamdani won the Democratic Party nomination for mayor. Ackman asked his social media followers to crowdsource some names for potential Mamdani opponents, and he said he would do a poll of followers based on the suggestions. Ackman said he wanted to do the crowdsourcing because he didn’t want his support for President Donald Trump to taint any potential candidate he would support. 31
In July 2025, Ackman called on Andrew Cuomo to leave the race, claiming that New York City Mayor Eric Adams (D) could defeat Mamdani. Ackman criticized Curomo’s “body language, his subdued energy and his proposals to beat Mamdani, [make it clear] that he is not up for the fight.” 32
In September 2025, Ackman called on Mayor Adams to end his reelection campaign and he announced his endorsement of former Governor Cuomo for mayor. Ackman said that Mayor Adams’s poll numbers had deteriorated since the Democratic primary and that Adams could not beat Democratic nominee and self-described socialist Zohran Mamdani. 33
Ackman has donated more than $600,000 to Democratic campaigns including those of Barack Obama, Al Gore, former South Bend mayor Pete Buttigieg, former Rep. Beto O’Rourke (D-TX), former Chicago mayor Rahm Emanuel, Sen. Chuck Schumer (D-NY), and the Democratic Senatorial Campaign Committee. 15