Investor Ackman takes $5.5 billion stake in Cadbury owner Mondelez

Ackman, CEO and portfolio manager of Pershing Square Capital Management, L.P., speaks at the Ira Sohn Investment Conference in New York

Activist investor William Ackman has built a stake worth about $5.5 billion in Mondelez International Inc (MDLZ.O), the maker of Cadbury chocolate and Oreo cookies, in what is seen as an attempt to push the company to boost earnings or sell itself.