Notes

The G20 (or Group of Twenty) is an intergovernmental forum comprising 19 countries and the European Union (EU). Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, the United Kingdom and the United States of America. Each year, the Presidency invites guest countries, which take full part in the G20 exercise. Several international and regional organizations also participate, granting the forum an even broader representation. It works to address major issues related to the global economy, such as international financial stability, climate change mitigation, and sustainable development.
The G20 is composed of most of the world's largest economies, including both industrialized and developing nations. The group collectively accounts for around 90 per cent of gross world product (GWP), 75-80 per cent of international trade, two-thirds of the world's population, and roughly half the world's land area.
In 1999, in the wake of the 1997 economic crisis, the G7 Finance Ministers announced the creation of the “Group of 20”, aimed at including other countries in their discussions related to global economics and finance. The first official meeting of the G20 was held in Berlin in December that same year.
Following the 2008 financial crisis, the United States proposed to increase the level of participation of the G20 to Heads of State and Government.
At the 2009 Pittsburgh Summit, the Heads of State and Government decided to institutionalize the G20 as the main forum for global economic and financial cooperation.
The G20 Leaders have met every year since 2010.
The G20's primary focus has been governance of the global economy. Summit themes have varied from year to year.

The G20 operates without a permanent secretariat or staff. The group's chair rotates annually among the members and is selected from a different regional grouping of countries. The incumbent chair establishes a temporary secretariat for the duration of its term, which coordinates the group's work and organizes its meetings. The 2019 chair was Japan, which hosted the 2019 summit in Osaka. The current chair is held by Italy. The 2021 summit is planned to be held in Italy. 2022, 2023 and 2024 summits will be hosted by Indonesia, India and Brazil respectively.

The G20's prominent membership gives it a strong input on global policy despite lacking any formal ability to enforce rules. There are disputes over the legitimacy of the G20, and criticisms of its organisation and the efficacy of its declarations.

The G20's transparency and accountability have been questioned by critics, who call attention to the absence of a formal charter and the fact that the most important G20 meetings are closed-door.