Jerome Kerviel cost Data Generale $ 6 billion in unauthorized trading by 2008 . John Lewis lost over $ 700 million in currency trading at the bank by 2002 . In January 1995 , Leeson bet that the Japanese Nikkei index would rise after performing poorly the previous year , but his timing could not have been worse -- the Kobe earthquake on January 17th , the worst in Japan in 70 years , sent stock prices plummeting . $ ##el 's $ 1.3 billion in losses brought down Britain 's Barings Bank in 1995 .
Jerome Kerviel cost Data Generale $ 6 billion in unauthorized trading by 2008 . John Lewis lost over $ 700 million in currency trading at the bank by 2002 . $ ##el 's $ 1.3 billion in losses brought down Britain 's Barings Bank in 1995 .