The five largest, non state-owned energy companies worldwide (ExxonMobil, BP, Royal Dutch Shell, Chevron and Total) are termed supermajors and hold about 3 per cent of global hydrocarbon reserves. They were created from the late 1990s to hedge against oil price volatility, achieve economies of scale and reinvest cash reserves. While the supermajors got bigger, so did the challenges they face, with implications for their survival.

The good news is that scale is an advantage when exploring for hydrocarbon resources in the most inhospitable and inaccessible parts of the world, in developing technology, in undertaking mega-projects.