The supermajors are considered to be BP plc, Chevron Corporation, ExxonMobil Corporation, Royal Dutch Shell plc and Total SA, with ConocoPhillips Company also sometimes described as forming part of the group.
The history of the supermajors traces back to the "Seven Sisters", the seven oil companies which formed the "Consortium for Iran" cartel and dominated the global petroleum industry from the mid-1940s to the 1970s.
The Seven Sisters were:
- Anglo-Persian Oil Company (now BP);
- Gulf Oil, Standard Oil of California (Socal) and Texaco (now Chevron);
- Royal Dutch Shell; and
- Standard Oil of New Jersey (Esso) and Standard Oil Company of New York (Socony) (now ExxonMobil).
The supermajors began to emerge in the late-1990s, in response to a severe fall in oil prices. Large petroleum companies began to merge, often in an effort to improve economies of scale, hedge against oil price volatility, and reduce large cash reserves through reinvestment.
The following major mergers and acquisitions of oil and gas companies took place between 1998 and 2002:
- BP's acquisitions of Amoco in 1998 and of ARCO in 2000;
- Exxon's merger with Mobil in 1999, forming ExxonMobil;
- Total's merger with Petrofina in 1999 and with Elf Aquitaine in 2000, with the resulting company subsequently renamed Total S.A.;
- Chevron's acquisition of Texaco in 2001; and
- the merger of Conoco Inc. and Phillips Petroleum Company in 2002, forming ConocoPhillips.
This process of consolidation created some of the largest global corporations as defined by the Forbes Global 2000 ranking, and as of 2007 all were within the top 25. Between 2004 and 2007 the profits of the six supermajors totaled US$494.8 billion.
Composition and present status 
Trading under various names around the world, the supermajors are considered to be:
- BP plc (United Kingdom);
- Chevron Corporation (United States);
- ExxonMobil Corporation (United States);
- Royal Dutch Shell plc (Netherlands and United Kingdom); and
- Total SA (France).
ConocoPhillips Company (United States) is also sometimes described as forming part of the group. As of 2011 ExxonMobil ranked first among the supermajors measured by market capitalization, cash flow and profits.
As a group, the supermajors control around 6% of global oil and gas reserves. Conversely, 88% of global oil and gas reserves are controlled by the OPEC cartel and state-owned oil companies, primarily located in the Middle East. A trend of increasing influence of the OPEC cartel, state-owned oil companies in emerging-market economies is shown and the Financial Times has used the label "The New Seven Sisters" to refer to a group of what it argues are the most influential national oil and gas companies based in countries outside of the OECD, namely CNPC (China), Gazprom (Russia), National Iranian Oil Company (Iran), Petrobras (Brazil), PDVSA (Venezuela), Petronas (Malaysia), Saudi Aramco (Saudi Arabia).
"Big Oil" 
Petroleum and gas supermajors are sometimes collectively referred to as "Big Oil", a term that emphasizes their economic power and perceived influence on politics, particularly in the United States. Big Oil is often associated with the Energy Lobby.
Usually used to refer to the industry as a whole in a pejorative or derogatory manner, "Big Oil" has come to encompass the enormous impact crude oil exerts over first-world industrial society.
See also 
- "Oil majors' output growth hinges on strategy shift". Reuters. 1 August 2008. Retrieved 28 April 2011.
- "Shell will invest despite decline in earnings". The New York Times. 2 February 2006. Retrieved 28 April 2011.
- "ConocoPhillips: The Making Of An Oil Major". Business Week. 12 December 2005. Retrieved 2006-09-29.
- The new Seven Sisters: oil and gas giants dwarf western rivals, by Carola Hoyos, Financial Times. 11 March 2007
- "Business: The Seven Sisters Still Rule". Time. 11 September 1978. Retrieved 24 October 2010.
- "Slick Deal?". NewsHour with Jim Lehrer. 1998-12-01. Retrieved 2007-08-20.
- Global 500, Fortune website, accessed Aug. 2008.
- Forbes Global 2000 – 2011 list
- FT list of top Publicly Traded companies
- Energy Information Administration (2009). Who are the major players supplying the world oil market?.
- "Shaky industry that runs the world". The Times (South Africa). 24 January 2010. Retrieved 26 October 2010.
- . ypenergy.org New and Old Leaders in the Upstream Oil Industry http://www.ypenergy.org/history/ New and Old Leaders in the Upstream Oil Industry. Retrieved 20 Jan 2012. Missing or empty
- . FT FT – New and Old Leaders in the Upstream Oil Industry http://www.warregoenergy.com/story/documents/FT%20The%20New%20Seven%20Sisters.pdf FT – New and Old Leaders in the Upstream Oil Industry. Retrieved 20 Jan 2012. Missing or empty
- Inside the Big Oil Game at Time
Further reading 
- Blair, John Malcolm (1976). The Control of Oil. Pantheon Books. ISBN 0-394-49470-9.
- Painter, David S. (1986). Oil and the American Century: The Political Economy of US Foreign Oil Policy, 1941–1954. Baltimore, MD: Johns Hopkins University Press. ISBN 978-0-801-82693-1.
- Yergin, Daniel (1993). The Prize: The Epic Quest for Oil, Money & Power. New York, NY: Free Press. ISBN 0-671-79932-0.
- "Crude Awakening", NOW, week of 16 June 2006.
- "Big Oil's bigtime looting", editorial from the Boston Globe, 2 September 2005.
- "Big Oil bears brunt over gas prices", Reuters, 23 October 2005.
- "In heated hearings, oil bosses defend big profits", Associated Press (via CNN), 9 November 2005.
- List of World's Largest Oil and Gas Companies Ranked by Reserves
- Who are the major players supplying the world oil market?