Every two months, representatives from the world's largest banksmeet at an undisclosed location to review the London interbankoffered rate.

Who sits on the British Bankers' Association's Foreign Exchangeand Money Markets Committee, the body that governs the benchmarkfor more than $300 trillion of securities worldwide, is a secret.No minutes are published. The BBA won't identify any members,saying it wants to protect them from being lobbied, and declined tomake the chairman available for interview.

The group's lack of transparency is symptomatic of aself-regulated system that failed to stop traders around the worldmanipulating the world's most widely used benchmark interest ratefor profit. Martin Wheatley, the British regulator charged withreviewing Libor after the scandal, is now weighing whether to bringoversight under the control of regulators.