Senior employees at its Singapore-based subsidiary Dynamic Oil Trading (DOT) are said to be under investigation.

“The extent of the fraud is not yet clear, but preliminary findings suggest a potential loss of around $125m,” OW Bunker said.

It added: “For the time being, the financial impact cannot be assessed; however, it must be assumed that the group's equity is lost.”

OW said it had been unable to find a solution with its syndicate banks after the fraud came to light.

“On