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 Italian candy maker behind Ferrero Rocher and Nutella is nearing a deal to buy cereal maker WK Kellogg , a source told Reuters, an acquisition that would combine two of the world's best known consumer food makers.

Ferrero, the European confectionery giant behind Nutella and Ferrero Rocher, is set to acquire WK Kellogg Co ., the maker of Froot Loops and other classic American cereals, in a $3.1 billion deal, according to a press release issued Thursday.