(CNN) — Activist investor Bill Ackman is making a big bet on coffee. His hedge fund just invested about $900 million in Starbucks. He made the announcement during a conference in New York on Tuesday, according to Ackman’s fund, Pershing Square Capital. Pershing acquired 15.2 million shares of the coffee company. During his presentation, Ackman outlined why he thinks Starbucks is a good bet. The company still has room to add stores in the United States, he said. And because of its generous wage and benefits plan, it won’t suffer if the minimum wage goes up.