Bill Ackman, founder and CEO of Pershing Square Capital Management.Bill Ackman, founder and CEO of Pershing Square Capital Management.

One of the most colorful battles in Wall Street history took place when investor Bill Ackman engaged in vocal activist short selling campaigns.

Despite our limited participation in this investment strategy, it has generated enormous media attention. The two short activist investments managed to inspire a book and a movie, Ackman said in his annual letter.

His five-year battle against Herbalife ended with huge losses. The founder and CEO of Pershing Square Capital Management placed a big bet against the company he accused of running a pyramid scheme.

Ackman said in the letter that they exited because they believed the capital could be better used in other opportunities.

At the height of his fight against Herbalife, Ackman engaged in an on-air verbal brawl with Carl Icahn. When the Wolves Bite: Two billionaires, one company, and an epic Wall Street Battle was written by Scott Wapner.

The great financial crisis turned out to be a success for Ackman, who shorted mortgage loan companies in 2007.

Ackman said he is ready to take his firm to the next era to focus on long-term bets.

We have built a reputation as a constructive, long-term, and helpful owner because we have had the opportunity to get to know many boards and management teams. We intend to keep it that way as it makes our job easier and more enjoyable. If it is helpful to call this approach quieter, let it be.

Ackman became a top 20 shareholder after buying over 3 million shares of the company. The activist investor built a new stake in Canadian Pacific Railway, a company that he helped transform years ago.

About 30% of our equity portfolio is invested in music and video streaming, while 26% is invested in restaurants and restaurant franchising. He owns stakes in several companies.

We expect that each of these companies will grow their revenues and profitability over the long term, regardless of recent events and the various other challenges that the world will face over the short, intermediate, and long-term.