ConocoPhillips' (COP.N) plan to split itself into two stand-alone public companies marks a reversal from a nearly 15-year trend of consolidation among big oil companies.
Since the late 1990s, global oil companies have combined into a small group of huge players known as super majors.
ConocoPhillips is the first of these to announce a plan to go in the other direction, as it bets that its production and refining arms would be worth more as separate companies.
Below is a timeline of some of the major oil industry deals from the past decade and a half:
December 1998: The U.S. Federal Trade Commission approves British Petroleum Co Plc's $55 billion acquisition of Amoco Corp. The new BP Amoco Plc became Britain's biggest company and the third-largest oil company in the world. The company is now BP Plc (BP.L).
September 1999: French oil groups TotalFina and Elf end a months-long takeover battle and agree on a merger. The deal was valued at 52.6 billion euros. The company is now Total SA (TOTF.PA).
November 1999: The U.S. government approves Exxon Corp's $82 billion purchase of Mobil Corp. The acquisition created Exxon Mobil Corp (XOM.N), the largest publicly traded oil company in the world.
April 2000: One day after unexpectedly delaying an announcement, the FTC approves BP Amoco Plc's purchase of Atlantic Richfield Co, or Arco, for $27 billion. The deal was approved after Arco sold its Alaska operations for $7 billion.
September 2001: The FTC allows Chevron Corp (CVX.N) to complete its $39.5 billion deal to buy Texaco Inc.
August 2002: Shareholders and the FTC approve an $18 billion union between Conoco Inc and Phillips Petroleum Co that creates the third-largest U.S. oil company. The merger created ConocoPhillips.
December 2005: ConocoPhillips pays $33.8 billion for exploration and production company Burlington Resources Inc.
(Source: Reuters News stories)