A former Swiss banker has passed on data containing account details of 2,000 prominent people to Wikileaks founder Julian Assange.
The data - which is not yet available on the Wikileaks website - was held on two discs handed over by Rudolf Elmer at a press conference in London.
Mr Assange promised full disclosure once the information had been vetted.
Mr Elmer is scheduled to go on trial in Switzerland on Wednesday for breaking bank secrecy laws.
The banker, who has given data to Wikileaks before, was fired from Swiss bank Julius Baer in 2002.
"Evidently disgruntled and frustrated about unfulfilled career aspirations, Mr. Elmer exhibited behaviour that was detrimental and unacceptable for the Bank, which led to termination of the employment relationship," the bank said in a statement sent to BBC News.
"After his demands (including financial compensation) in connection with the dismissal could not be satisfied, Mr. Elmer embarked in 2004 on a personal intimidation campaign and vendetta against Julius Baer," the statement read. BBC News
