Suggested Citation:
Jaffe, Amy Myers and Ronald Soligo (2007) The International Oil Companies. James A Baker III Institute for Public Policy

The 1990s witnessed highly volatile oil prices and with them, a wave of consolidations in the international energy world that has brought about a structural shift in the industry still being played out today. In 2005, Petroleum Intelligence Weekly (PIW) “Top 50” oil companies’ annual ranking no longer included five companies—Mobil, Texaco, ARCO, Amoco, and Unocal—that had ranked in the top 40 back in 1995. Of the so-called “Seven Sisters” that dominated the world oil scene in the aftermath of World War II, only four remain, now commonly referred to as the IOCs (international oil companies) and including in their ranks one additional megafirm created by the merger of two large independents, Conoco Inc. and Phillips Petroleum Co. Similar consolidations have occurred in Canada, Europe, and Japan.