to a bank in unauthorized trading. Rogue trader Jerome Kerviel cost his French bank, Societe Generale, almost $6 billion, and was sentenced to three years in prison last year. Yasuo Hamanaka cost Sumitomo Corporation $2.6 billion in the global copper market, and was sent to prison for eight years over fraud and forgery in 1997. Nick Leeson, the subject of the Ewan McGregor movie Rogue Trader, lost about $1.3 billion for his bank, Barings, in 1995, forcing it to close. UBS is not likely to collapse, but the scandal could prompt the bank to split its investment bank into a separate company, van Dam said. There is a much higher chance that this bank will now be broken up into a wealth managament firm and an investment bank to reduce clientsexposure to investment banking losses, he said. He favors that alternative, he said. The banks are too large, van Dam said. The products are so complicated, and the management does n't understand it. UBS made a pre-tax profit of about $1.9 billion in the second quarter of this year, it announced in July, down from about $2.5 billion the quarter before that. CNN's Nina dos Santos, Irene Chapple, Ben Rooney, Alex Mohacs, James Partington, Laura Perez Maestro, Kendra Petersen, Nick Thompson and Christine Theodorou contributed to this report.