8. Toshihide Iguchi
No one can accuse Toshihide Iguchi of poor work ethic: The former Daiwa Bank executive made more than 30,000 trades over an 11-year period. Unfortunately, the trades were unauthorized, and involved U.S. Treasury bonds from the firm’s custodial account. Iguchi eventually racked up more than $1 billion in losses, which he unsuccessfully tried to cover up by falsifying records.
Iguchi’s exploits earned him a four-year prison sentence and $2.6 million in fines. But the ex-trader apparently looked at the scandal as a learning experience, later writing a book called “My Billion Dollar Education.”