Nick Leeson of Barings Bank, Toshihide Iguchi of Daiwa Bank, Yasuo Haminaka (Mr. Cooper) of Sumitomo, John Rusnak of Allfirst Bank, Chen Juilin of China Aviation Oil Corporation, Jerome Kerviel of Société Générale, and more recently, Bruno Iksil of JP Morgan (the London Whale)… were all people who made large trading losses. What goes on in a trader’s m