The G-20 is a group of finance ministers and central bank governors from 20 economies: 19 of the world's largest national economies, plus the European Union (EU).
Collectively, the G-20 economies are responsible for 85 per cent of global gross national product, 80 per cent of world trade and two-thirds of the world population.
This year's London meeting involves world leaders, in addition to their finance ministers and governors. The global financial crisis has led the G-20 to elevate the status of this year's gathering.
The G-20 is a forum for cooperation and consultation on matters pertaining to the international financial system.
It studies, reviews, and promotes discussion among key industrial and emerging market countries of policy issues pertaining to the promotion of international financial stability, and seeks to address issues that go beyond the responsibilities of any one organisation.
The European Union