Frankfurt - Deutsche Bank has widened an internal probe into possible manipulation of the Libor benchmark interest rate after discovering a new chatroom where traders may have colluded, a source familiar with the matter said on Monday.
Another source said Deutsche had summoned around 50 employees for questioning as a result of the discovery. The bank declined to comment.
More than a dozen banks and brokerage firms, including JP Morgan and Citigroup, are being investigated by regulators over the possible manipulation of benchmark interest rates - including the London interbank offered rate, known as Libor - which are used to price trillions of dollars' worth of loans.
Deutsche says it is cooperating with investigators, but has also conducted an internal inquiry, led by its legal department, which resulted in the suspension of five Frankfurt-based traders in February.
Four of these traders successfully sued Deutsche for unfair dismissal in September, and revealed fresh evidence about how the bank set interbank lending rates.