Shares of food giant and Cheerios cereal maker General Mills(GIS) - Get Report rose almost 7% on Thursday after the company said its longtime CEO Ken Powell would leave the company, a move that has Wall Street wondering is a long-expected change of strategy, including a possibility of a takeover may be in the offing. 

Powell will remain Chairman for a transition period until his retirement, probably within the year.

General Mills shares traded at $59.86 Thursday morning, up $3.8.

Investors have been eyeing General Mills and Powell's role since it said in December 2016 that it would reorganize it into four segments: North America Retail, Europe and Australia, Asia and Latin America, and Convenience Stores and Foodservice.

Each segment will have its own leader. Each will report directly to Jeff Harmening, General Mills' current president, and COO. Global operations functions such as innovation, technology and quality and supply chain will continue to report to Harmening.

Long rumored to be Powell's successor, Harmening, who like Powell has spent his entire career at General Mills, was promoted to his current role in July. Before that, he was COO of the company's U.S. retail business, overseeing areas such as baking, cereal, snacks, and yogurts.