Kellogg beat Wall Street expectations for quarterly sales and profit, boosting the food maker’s shares over 9% as investments in marketing and product development drove higher demand for snacks and frozen food in North America.

Activist investor William Ackman has built a stake worth about $5.5bn (€5.05bn) in Mondelez International, the maker of Cadbury chocolate and Oreo biscuits, in what is seen as an attempt to push the company to boost earnings or sell itself.