The hedge fund billionaire tells CNBC the past 12 months were the "worst period of performance" of his career, and the implosion of Valeant was mostly to blame.
Bill Ackman and David Einhorn are considered two of the top hedge fund managers in the world, but they might as well be on a seesaw.
Hedge funds suffered the worst withdrawals last quarter since the tail-end of the financial crisis as wild swings in stocks and commodities caused losses at some of the best-known firms.
After Valeant took a giant bite out of Bill Ackman's hedge fund, the billionaire described his firm's standing to CNBC's Scott Wapner.
Activist investor Bill Ackman has trimmed his stake in embattled drugmaker Valeant Pharmaceuticals.
At an event honoring Warren Buffett's 50 years at Berkshire Hathaway, Bill Ackman openly criticized Buffett for his stake in Coca-Cola.
'A fairly remarkable phenomenon and I think kind of a frightening one'.
Bill Ackman appears set to take it relatively easy for a few months after a slew of activist investments produced knockout performance in 2014.
Success beyond your wildest dreams.