Activist investor Ackman paying about $5.5B for 7.5 pct stake in snack maker Mondelez

Activist investor Bill Ackman is paying approximately $5.5 billion for a 7.5 percent stake in Mondelez International Inc.

Ackman's Pershing Square Capital Management LP is buying about 120.3 million shares of the snack maker.

Mondelez's stock rose 8 percent in Thursday premarket trading.

Mondelez, the maker of products including Oreo cookies and Cadbury chocolate, split off from Kraft in 2012. Kraft kept the North American grocery brands and Mondelez took the snacks.

Kraft is now set to combine with H.J. Heinz to form The Kraft Heinz Co., creating one of the world's biggest food companies with brands such as Jell-O and their namesakes. Heinz' owners, Warren Buffett's Berkshire Hathaway and the Brazilian investment firm 3G Capital, engineered the deal.

Last month Mondelez, which is based in Deerfield, Illinois, posted better-than-expected second-quarter earnings because of lower costs.