Ackman's $14.5 billion Pershing Square Capital Management paid roughly $186 per share for its 21.4 million shares of Valeant. The stock closed at $72.58 on Wednesday. Last year, the hedge fund was one of the industry's best performers with a 40 percent gain. Pershing Square has several portfolios with Pershing Square Holdings being the most aggressive, so the losses are modestly less at its other portfolios, a person familiar with the numbers. NEW YORK - Many big companies follow a strategy of stock buybacks and acquisitions. Critics argue these moves cannibalize innovation and slow growth. Special Report