5. Yasuo Hamanaka: Lost $2.6 Billion

Yasuo Hamanaka is a former Chief Copper Trader at Sumitomo Corporation. So, he is also called ‘Mr. Copper.’ He also got his pseudonym because of his aggressive style of trading. He was also called ‘Mr. Five Percent’ as he was in charge of over 5 percent of the copper supply of the world. His reputation tumbled during 1986 to 1996, when his name started being associated with rogue trading. He was even said to have a membership of price-fixing conspiracy. In 1996, Sumitomo Corporation reported losses of about $1.8 billion, all arising from the unauthorized copper tradings on the London Metal Exchange by Hamanaka. BY September 1996, he reported these losses to be over $2.6 billion. On these very charges, he served time in prison from the year 1998 to 2005.