James Wolfensohn, the 71-year-old Australian-born American, says he expects to step aside when his second five year term as World Bank president expires in June.

Nominated by former President Clinton, Mr. Wolfensohn heads the world's biggest development institution, providing about $20 billion a year in loans and grants to developing countries. Washington Post columnist Sebastian Mallaby recently published a book about Mr. Wolfensohn's 10 years of leadership at the Bank. He leaves office, says Mr. Mallaby, with three central achievements.

The first is to put corruption on the agenda. It had been a taboo to talk about corruption and its relation to development before his arrival in 1995," he said. "Jim Wolfensohn shattered that taboo and now the World Bank has recognized that you have to think not just of economic policy but the quality of your institutions. And corruption goes to the heart of that."

Mr. Mallaby says decentralization and a shift towards developing countries themselves taking responsibility for aid programs are his other achievements.

The Bush administration has the main responsibility for nominating a successor to Mr. Wolfensohn. Mr. Mallaby expects the Americans to adhere to the tradition that, while a European leads the International Monetary Fund, an American heads the World Bank. Mr. Mallaby says U.S. Trade Representative Robert Zoellick is probably the front-runner to succeed Mr. Wolfensohn.

"If you look at from the point of view of which of the names out there that would be best for the bank, he [Zoellick] is the best candidate, he said. However, he is such a dynamic figure that it wouldn't surprise me at all if he were to be tapped for another job instead.

Observers say it is likely to be several weeks or even months before a successor for Mr. Wolfensohn is known.