Giovanni Ferrero has expanded his family's company beyond brands like Nutella and built a global powerhouse—especially through big acquisitions in the U.S.

The $3.1 billion acquisition would combine Ferrero, which makes Tic Tacs and Nutella, with the producer of Frosted Flakes and Froot Loops.

WK Kellogg shares skyrocketed by approximately 50% in pre-market trading following news that Italian confectionery giant Ferrero plans to acquire the American cereal manufacturer for $3.1 billion