The startling spike in oil prices to their highest level this year on Tuesday was caused by a rogue broker who placed a massive bet in the Brent oil market, triggering almost $10m (€7m) of losses for his company.

PVM Oil Associates, the world’s largest over-the-counter oil brokerage, said on Thursday it had been the “victim of unauthorised trading”. The privately owned company said that as a result of the unauthorised trades it had been forced to close substantial volumes of futures contracts at a loss.

Oil traders in London and New York said the “unauthorised trading” explained the exceptional spike in business activity and prices in the early hours of Tuesday that some initially thought must have been caused by a geopolitical event. “Trading volumes rose overnight and prices jumped more than $2 a barrel without apparent justification,” a senior oil trader in New York said.