Nick Leeson 's cost Societe Generale $ 1.3 billion in unauthorized trading by 2008 . Nick Leeson 's lost over $ 6 billion in currency trading at Allfirst bank by 2002 . Nick Leeson 's $ 1.3 billion in losses brought down Britain 's Barings Bank in 2008 .
Jerome Kerviel cost Societe Generale $ 6 billion in unauthorized trading by 2008 . John Rusnak lost over $ 700 million in currency trading at Allfirst bank by 2002 . Nick Leeson 's $ 1.3 billion in losses brought down Britain 's Barings Bank in 1995 .