There's a mood of consolidation in the air in the US oil industry - earlier this month Exxon Mobil, the largest American oil-producer, bought oil-explorer Pioneer Natural Resources for $59.5bn. Now Chevron has announced its buying its main rival Hess for $53bn.

The oil industry last went through an era of major consolidation in the late 1990s, following a collapse in oil prices. That's not the case now.

Today, the majors are sitting on piles of cash.

(Picture: Blue Metal Oil Barrels Stacked In A Warehouse. Picture credit: Getty Images)