Loss: $2.6 billion
As the chief copper trader at Sumitomo, Hamanaka executed $2.6 billion worth of unauthorized trades over a 10-year period, artificially inflating prices and generating huge revenue for the bank. At one point he controlled 5 percent of the world’s copper, which gave earned him the nickname "Mr. Five Percent." In 1997, Hamanaka was sentenced to eight years in prison for fraud and forgery. He was released in July 2005, after having served 7 years.
Photographer: Getty Images