Bunker prices, in almost perfect lockstep with the price of crude for decades, have shown a tight gap between wholesale to suppliers and retail to shipowners, but that mechanism may be dismantled for high-sulphur fuel oil (HSFO) in 2020.

When the IMO cuts the amount of sulphur permitted in shipping fuel, HSFO may not be as cheap as some owners expect, according to 30-year marine-fuel veteran Adrian Tolson, who started Stamford consultancy 20|20 Marine Energy in 2015.