Jim Yong Kim has abruptly resigned as president the World Bank, more than three years ahead of schedule.
The 59-year-old Kim will "join a firm and focus on increasing infrastructure investments in developing countries," the Washington-based bank said on January 7.
No reason was given for his unexpected resignation.
Kim is stepping down after six years in the post.
He was not due to leave until 2022, after he was reelected for a second five-year term in 2017.
Kristalina Georgieva, the bank's chief executive officer, will assume the role of interim president on February 1.
The head of the World Bank has traditionally been an American, while the managing director of the International Monetary Fund is typically European.
However, some countries have been pushing for a representative from emerging markets.