Developing countries will have a greater say in running the World Bank
US Treasury secretary Timothy Geithner has said that World Bank members have agreed to two new developments.
They will raise extra capital and give more of a voice on running the organisation to developing countries.
Mr Geithner said the Bank had made a "strong and compelling case" for a funding increase of $3.5bn (£2.3bn).
He said the money was needed to help Afghanistan to develop more productive farming and for relief efforts, such as that currently underway in Haiti.
Mr Geithner said in a statement that the new shareholding formula was fairer: "We can feel proud that we have concluded agreements on a transformative financial and governance reform agenda, along with new capital for the World Bank and a new and more representative shareholding formula."
He also said that the United States, which holds the largest voting share in the World Bank at 16.4%, would not seek any increase to that.
The extra funding will need to be agreed by the US Congress.