“The guy is a major loser”. 

That’s what Carl Icahn called fellow billionaire investor Bill Ackman in Wall Street’s most famous fight. Few get tempers tetchier than Ackman: his contrarian approach to investing has attracted plenty of enemies. But if you can get past his “sanctimonious” demeanor (Icahn again), there’s a lot to be learned from Bill: you don't become a self-made billionaire without doing something right.

Who is Bill Ackman?

He’s the 53-year-old founder and CEO of Pershing Square Capital Management, a $9 billion investment firm. Over the past twenty years he’s made a name for himself as one of the most outspoken and headstrong investors around, making one risky bet after another. And while those haven’t all worked out, Ackman’s done pretty well overall: delivering his investors a 635% return since 2004.

Source: Pershing Square Capital Management

How did he manage that? Ackman’s investment philosophy isn’t too different from Warren Buffett’s – no surprise, as both of them describe Ben Graham’s book The Intelligent Investor as having had a big influence on their way of operating.

Ackman’s a “value investor”: he looks for good, hard-to-compete-with companies that he thinks the market’s underestimating. He then holds on to investments in those firms while they grow in value. Ackman doesn’t like the term “hedge fund”; he prefers to refer to Pershing as an “investment holding company”, to highlight this lack of short-term flips.

"I'm not a trader."

- Bill Ackman

Ackman puts his own spin on the Buffett approach, however: he’s an “activist investor”.