Bill Ackman is one of the most widely followed investment managers in the world. He's in charge of Pershing Square Capital, a hedge fund focused on investing in just a handful of Ackman's best ideas. His highly concentrated portfolio is full of great companies, but he might have just made one stock the biggest holding at Pershing Square.

Go big or go home. Billionaire investor Bill Ackman of Pershing Square Capital Management takes that sentiment to heart. His hedge fund has some $13 billion in assets under management, but he owns just 10 stocks (track his portfolio here),

Hedge fund manager Bill Ackman just disclosed a position in Uber. Bill Ackman is one of the most closely followed investment personalities on Wall Street. As CEO of hedge fund Pershing Square Capital Management, Ackman has been at the center of some creatively structured investments in recent history.

William Albert Ackman, more commonly known as Bill Ackman, is the founder and CEO of Pershing Square Capital Management, a hedge fund management company.

Billionaire investor Bill Ackman's Pershing Square Capital acquired a $2.3 billion stake in Uber by purchasing 30.3 million shares. Ackman has praised Uber's CEO for transforming the company and also claimed that the company has more scope for growth.

Billionaire hedge fund manager Bill Ackman recently revealed his latest multibillion-dollar investment: mobility technology leader Uber (NYSE: UBER). According to a social media post by Ackman, Pershing Square Capital Management (the hedge fund he oversees) owns 30.