Activist investor William "Bill" Ackman is the head of Pershing Square Capital Management and one of the most recognizable investors on Wall Street. He is best known for his, and his company's, loud stance on Herbalife Ltd. (NYSE: HLF), a move that created a series of dramatic back-and-forth exchanges between Ackman and fellow activist titans Carl Icahn and Daniel Loeb. Personally, Ackman is notorious for an unrelenting drive to win and his high self-confidence.

Early Life and Education

Raised in Chappaqua, New York, to a wealthy Jewish family, Bill Ackman had many advantages in life. He took advantage of his opportunities, studying hard as a child and gaining a reputation as a know-it-all who knew he knew it all. Ackman graduated magna cum laude in 1988 from Harvard University with a degree in history. Four years later, he earned his Master's in Business Administration (MBA) from Harvard Business School. Later, Ackman returned and served as a member of the Board of Dean's Advisors for the Harvard Business School.

Success Story

Shortly after his graduation from Harvard Business School, Ackman founded Gotham Partners with David P. Berkowitz. Gotham Partners was a small investment firm that focused on a diverse portfolio of public companies, a style far removed from Ackman's later investment strategies. Despite years of success early on, the fund eventually folded in 2002 after a decade of operation, largely due to a poor golf course investment and a public challenge from outside investors.

Two years after Gotham Partners wound down, Ackman founded Pershing Square Capital Management with $54 million from his personal funds. Over the next decade-plus, Pershing Square gained a reputation as a brutally effective negotiator and agitator of corporate change, earning significant influence with major companies such as J.C. Penney Company, Inc. (NYSE: JCP), General Growth Properties, Inc. (NYSE: GGP), Fortune Brands, Kraft Foods and others.

In more recent times, Ackman staked out headline-grabbing positions in Valeant Pharmaceuticals International, Inc. (NYSE: VRX), Air Products and Chemicals, Inc. (NYSE: APD) and Herbalife. His fund enjoyed record success in 2014, only to see its worst year ever in 2015. Even still, Pershing Square entered 2016 with $18.5 billion in assets under management (AUM).

Net Worth and Current Influence

As of February 2016, Bill Ackman has a net worth of $1.96 billion and ranks 256 on the Forbes 400 list. Almost of Bill Ackman's professional income has been earned in the market as a portfolio manager, although he worked with his father in real estate for a few years. Along with his business success, Bill Ackman is a noted philanthropist. With his wife Karen, Ackman founded The Pershing Square Foundation in 2006 to support education, health care, human rights and the arts. This foundation granted and invested more than $160 million in charity efforts between 2006 and 2015.

Most Influential Quotes

"Let me win? That doesn't exist in my house. No one lets anyone win. Fight to the death." Ackman gave this quote to the New York Times in 2014 about arguing with his parents as a child, highlighting his confident nature and the competitive household in which he grew up.

"They've never had someone like me prepared to say the truth about Herbalife. I'm going to the end of the earth. I had a moral obligation." Bill Ackman is considered a powerful and emotional public speaker, and he used those talents to blast Herbalife as a "Ponzi scheme" and fraud.

"Everyone told me it was a really stupid idea to start my own hedge fund right out of business school. That's how I knew that it was a good idea." Bill Ackman, like so many successful investors, has a strong individualist streak. He repeatedly speaks about tolerating and handling rejection and doubts, all while listening to one's own inner voice.

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