William Ackman, founder and CEO of hedge fund Pershing Square Capital Management, speaks during the Sohn Investment Conference in New York May 4, 2015. REUTERS/Brendan McDermid  Thomson ReutersWilliam Ackman, founder and CEO of hedge fund Pershing Square Capital Management, speaks during the Sohn Investment Conference in New York

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Disclaimer
Hedge fund titan Bill Ackman's Pershing Square Holdings, the fund's publicly traded vehicle, has fallen 14.5% in 2016, according to a performance update.
That performance is through January 19. 
Pershing Square had its worst year in its history last year, falling 20.5%. 
Ackman, a well-known activist investor, makes large, concentrated bets in a handful companies.
His five largest holdings include Valeant Pharmaceutical (-12% year-to-date), Air Products & Chemicals (-9.6%), Canadian Pacific (-18%), Mondelez (-9.3%), and Zoetis (-8.6%).
Ackman is also an investor in Platform Speciality Products, which has dropped 40% this year. Meanwhile, Howard Hughes Corp, another one of his long equity holdings, has fallen about 15%.
Ackman's only short is Herbalife, a multi-level marketing company that sells weight loss shakes. Ackman has been crusading against Herbalife since December 2012 because he believes the company is a "pyramid scheme." He's betting that the stock goes to $0. 
Shares of Herbalife have fallen more than 13% this year.