Fastfood giant McDonald's Corp. has announced the shock resignation of Mike Roberts, the company's president and chief operating officer and second highest ranking executive.

The company's CEO Jim Skinner made the announcement of Roberts' departure on Wednesday (23 Aug) evening but gave no reason for the resignation.

Roberts' position will be taken by Ralph Alvarez, president of McDonald's USA, while Don Thompson, currently executive vice-president and chief operations officer, will succeed Alvarez as head of the US business.

Skinner said: "We all owe Mike a tremendous debt of gratitude. Because of his leadership, our system is stronger and more aligned than ever."

The move is all the more surprising given the fact that Roberts was widely seen as a likely successor to Skinner as CEO.

Alvarez, 51, has been with McDonald's for 12 years. "I have tremendous confidence in Ralph's ability and look forward to working closely with him as we continue to evolve the business through our unwavering focus on our Plan to Win," Skinner said. "Ralph has an exemplary track record in both our domestic and international businesses. He is a tremendous leader and team player."

Don Thompson, 43, joined the fastfood group in 1990 as a restaurant systems engineer. In his role as executive vice-president and chief operations officer for McDonald's USA, he was responsible for restaurant operations in the US. He was previously executive vice-president and innovation orchestration leader, McDonald's Restaurant Solutions Group, and before that he served as president of the West Division of McDonald's USA.