billion stake in Netflix. Netflix stock had just experienced a precipitous 30% selloff after announcement of a disappointing subscriber growth outlook for Q1 2022. In a letter to its investors, Ackman praised Netflix's "best-in-class management team" and said he long admired Netflix CEO Reed Hastings and the "remarkable company he and his team have built." In April, Netflix stock fell by 35%, and Ackman responded by selling his entire stake in the company. Investment style Ackman has said that his most successful investments have always been controversial, and that his first rule of activist investing is to "make a bold call that nobody believes in". His most notable market plays include shorting MBIA's bonds during the financial crisis of 2007–2008, his proxy fight with Canadian Pacific Railway, and his stakes in the Target Corporation, Valeant Pharmaceuticals, and Chipotle Mexican Grill. From 2012 to 2018, Ackman held a US$1 billion short against the nutrition company Herbalife, a company he has claimed is a pyramid scheme designed as a multi-level marketing firm. His efforts were reported in the documentary film Betting on Zero. After weak performance in 2015–2018, Ackman told investors in January 2018 that he was going to go back to basics by cutting staff, ending investor visits that were eating into his time, and hunkering down in the office to do research. The next year, Pershing Square returned 58.1%, which Reuters says qualified it as "one of the world’s best performing hedge funds" for 2019. Ackman has said that he admires short sellers such as Carson Block of Muddy Waters Capital and Andrew Left of Citron Research. Philanthropy Ackman has given to charitable causes such as the Center for Jewish History, where he spearheaded a successful effort to retire $30 million in debt, personally contributing $6.8 million. The donation, along with those of Bruce Berkowitz, founder of Fairholme Capital Management, and Joseph Steinberg, president of Leucadia National, were the three largest individual gifts the center has ever received. Ackman's foundation donated $1.1 million to the Innocence Project in New York City and Centurion Ministries in Princeton, N.J. He is a signatory of The Giving Pledge, committing himself to give away at least 50% of his wealth to charitable causes. In 2006, Ackman, and then wife Karen, founded the Pershing Square Foundation to support innovation in economic development, education, healthcare, human rights, arts and urban development. The foundation is a major