A surge in bunker prices is driving a further wedge between the period rates commanded by modern and older tankers. An even bigger split in the market is looming, once ships are limited to using low-sulphur fuel oil.

Bunker prices have risen 16% since the start of April, to a global average of $458 per tonne. The increases are widening the gulf between the operating expenses of regular vessels and more fuel-efficient “eco” tankers.