The decision ends Kim's six-year tenure and may give US President Donald Trump decisive influence over the future leadership of the global development lender.

"It has been a great honor to serve as president of this remarkable institution, full of passionate individuals dedicated to the mission of ending extreme poverty in our lifetime," Kim said in a statement.

Kim, who became president in 2012, is to join an as-yet unnamed firm focusing on investments in developing countries, the bank said in a statement, and will return to the board of Partners-in-Health, which he co-founded.

Under Kim's leadership, the bank set the goal of eliminating extreme poverty by 2030 and ramped up financing.

Last year, it also won approval for a sharp $13 billion capital increase after acceding to requests from the Trump administration to curb loans to high-income countries like China.

Kim's tenure was also marked by high levels of disaffection among World Bank staff, who chafed at a widespread internal restructuring that Kim began.

World Bank CEO Kristalina Georgieva will serve as interim president upon Kim's February 1 departure, the bank said in a statement.