Ackman builds stake in Allergan, working with Valeant -sources
April 21, 2014 at 16:54 PM 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.
