LONDON - PVM Oil Associates, the world's biggest over-the-counter oil brokerage, says it lost nearly US$10 million (S$14.5 million) this week because of unauthorised trades that caused a temporary spike in Brent crude markets.

The firm said in a statement late on Thursday that it was investigating the trades, which drove up the price of Brent futures by more than US$2 in one hour early on Tuesday London time. It did not identify the trader involved in the transactions.

The Financial Times reported that futures contracts for 16 million barrels of oil changed hands in one hour, compared to a typical volume of 500,000 barrels.

PVM said the trading had been reported to the Financial Services Authority, but the government agency declined to say on Friday whether it was investigating.

A statement issued by PVM's managing director, Mr Robin Bieber, said that 'as a result of a series of unauthorised trades, substantial volumes of futures contracts were held by PVM'.

'When this was discovered, the positions were closed in an orderly fashion. PVM suffered a loss totalling a little under US$10 million.' -- AP