Ackman takes 9.9% stake in Chipotle….becomes second largest shareholder Posted on September 6, 2016 at 10:55 pm. Bill Ackman’s Pershing Square Capital Management acquired 2.88 million shares i.e. a 9.9% stake in Chipotle Mexican Grill, according to [Read More]To access this content, you must be a member. Visit the Plans page for details.