WASHINGTON — For the first time, the World Bank is considering more than one candidate for its five-year presidency — a change that reflects the fast-growing clout of emerging economies, even as it raises questions over whether that change is coming quickly enough.

Experts say that victory is all but assured for the American nominee, Jim Yong Kim, the president of Dartmouth College and an expert in global health. But emerging and developing economies are rallying behind Ngozi Okonjo-Iweala, the 57-year-old Nigerian finance minister, and José Antonio Ocampo, the former Colombian finance minister and high-ranking United Nations official, who is 59.

The World Bank’s 25-member board will interview all three candidates in the coming weeks and plans to announce its new president by the I.M.F.-World Bank meetings in mid-April. Robert B. Zoellick, the current president, will step down at the end of June.

Ms. Okonjo-Iweala and Mr. Ocampo have won the endorsement of a group of developing economies. And the United States is weathering criticism for the time-honored gentlemen’s agreement that ensures its control of the World Bank, even if the institution’s presidential selection process is opening up.