Container lines could be forced into mergers by the costs of IMO 2020 legislation.

That is the view of shipping consultancy Drewry, which believes some financially vulnerable carriers may have no choice as the low-sulphur rules pile on more expenses.

Lines made a combined "small profit" in the region of $1.5bn in 2018, Drewry estimated.

"Without wanting to be too alarmist, there is the potential for IMO 2020 to inspire another major carrier bankruptcy and/or trigger more defensive M&A," Drewry said.