Entertainment major Walt Disney has been thrown into an unexpected embarrassment after its Chief Operating Officer Thomas Staggs announced his resignation. The decision raised questions on the next CEO who will take over from Robert Iger who retires in 2018.

Staggs has been in the limelight for long as the CEO in waiting. His abrupt announcement raises questions about the company’s succession plan as well as the selection process.

The move has shocked the Wall Street and Hollywood and Disney’s stock tumbled in the afternoon trading, reports Los Angeles Times.

Industry circles were abuzz with expectations that Staggs will replace Iger by 2018. His sudden departure means Disney has to search hard for a new leader.

Staggs, 55, was named chief operating officer in early 2015 and was being groomed for the top post in the No 2 slot.

Reacting to the news, Disney said in a statement that its board of directors would “broaden the scope of its succession planning process to identify and evaluate a robust slate of candidates for consideration.”

Though Staggs will relieve his position on May 6, he will remain with Disney until the fiscal year gets over, Disney’s statement added.

Stagg spent 26 years in Disney and held many senior positions and was chief financial officer and head of the parks and resorts department in the past.

“Tom has been a great friend and trusted colleague for more than 20 years,” CEO Iger said in a statement.

He hailed Stagg’s contributions and recalled the wide respect he earned from the organization and appreciated his achievements and personal integrity.

Staggs, in a statement, praised Disney and Iger, saying: “Disney truly stands alone, not only because of the company’s phenomenal creativity but also because of the thousands of remarkable people who make it such an extraordinary place.”

Meanwhile,  a report in The Wall Street Journal said, Staggs decision to quit has been a fallout of the decision of the CEO and company’s board to broaden their search for a successor by adding more candidates.

Staggs perceived that he is being pitted against more odds in rising to the CEO job, the report said. It noted that the Disney board will have to scout for more external CEO candidates as none of its tier 2 executives are in a position to take up the top job.