"When Hamanaka confessed his unauthorised copper trading to his supervisor Akio Imamura on 5 June, he handed him a personal memorandum," one of the sources said.
The sources said they had not seen the so-called "Hamanaka memo", whose contents remained a closely guarded secret, but they said it was thought to explain how he carried out his unauthorised trades over 10 years. Whether the document indicates any specific names of metal trading companies outside Sumitomo could not be confirmed.
After Hamanaka's unauthorised trades and massive losses came to light, Sumitomo also cancelled the scheduled promotion of Mr Imamura, general manager of its non-ferrous metals division, to managing director.
Meanwhile, Wolfgang Becker, a metals broker, expressed concern about what he said were unsubstantiated rumours about his business dealings with Chile's state-owned copper producer Codelco and Sumitomo of Japan. Mr Becker said in a statement that he had resigned from Merrill Lynch in 1995 to form his own commodity brokerage based in Hamburg.
"My dealings with both these corporations have been totally above board and neither of them have ever approached me or my employers for any favours," Mr Becker said.Reuse content