Ackman builds stake in Allergan, working with Valeant -sources

BOSTON, April 21 Mon Apr 21, 2014 4:54pm EDT

BOSTON, April 21 (Reuters) - Activist investor William Ackman has acquired a nearly 10 percent stake in wrinkle-treatment maker Allergan Inc and is working with Valeant Pharmaceuticals International to buy the company, sources said on Monday.

For Ackman's Pershing Square, a $13 billion hedge fund, the investment is the biggest ever, coming less than one year after it made its last big bet on Air Products & Chemicals. (Reporting by Svea Herbst-Bayliss and Olivia Oran; Editing by David Gregorio)