Vikram Pandit, the chief executive officer of Citigroup, has stepped down, the company's board announced today.

"The Board also announced it has unanimously elected Michael Corbat CEO and a director of the Board," Citigroup said in a statement. "Mr. Corbat previously served as Citigroup's CEO of Europe, Middle East and Africa."

Pandit's resignation was effective immediately. As Business Insider reports, the succession was rumored but "shock resignations like this (especially resigning that day) are just not usually done, and don't inspire investor confidence."

The New York Times reports:

"The surprising move by Mr. Pandit comes just one day after the firm reported stronger-than-expected third-quarter earnings. Under Mr. Pandit's tenure, which began shortly before the financial crisis of 2008, Citi struggled through enormous market upheaval and needed several rescue lines from the government."But it has slowly recovered, in large by shedding big portions of its businesses. Among them is Smith Barney, the brokerage operation that is being absorbed by Morgan Stanley."

In a statement, Pandit said he was leaving Citigroup "well-positioned for continued profitability and growth."

He added:

"Given the progress we have made in the last few years, I have concluded that now is the right time for someone else to take the helm at Citigroup. I could not be leaving the Company in better hands. Mike is the right person to tackle the difficult challenges ahead, with a 29-year record of achievement and leadership at this Company. I will truly miss the wonderful people throughout this organization. But I know that together with Mike they will continue to build on the progress we have made."

Update at 9:39 a.m. ET. COO Also Resigns:

The Wall Street Journal reports that in light of Pandit's resignation, Chief Operating Officer John P. Havens also submitted his resignation.

The Journal adds:

"A senior Citigroup banker in Asia said the news came as a complete surprise. He said executives in Asia, Citigroup's fastest-growing regions, were blindsided by the news in part because they expected a well-orchestrated succession plan to be in place before Mr. Pandit resigned."Another executive at the bank said there was no inkling that Mr. Pandit, who was in the region last month, was thinking of resigning. The perception in Asia, the banker said, was he was getting settled in his post-crisis role of trying to boost the bank's growth."Copyright 2016 NPR. To see more, visit http://www.npr.org/.