Last week, UBS AG said a rogue trader racked up as much as $2 billion in losses using the firm’s own money. The losses is said to stem from unauthorized derivatives-trading bets by rogue trader Kweku Adoboli.

“Moody’s Investors Service said it was reviewing UBS’s credit rating for a possible downgrade, citing concerns about UBS’s reputation and its abilities to manage risk and rebuild its investment bank.”

If you recall, in January 2008, French bank Société Générale lost approximately €4.9 billion ($7.1bn) closing out positions over three days of trading beginning January 21, 2008, the bank claimed the losses was caused by Paris-based trader Jérôme Kerviel for his simple transactions, concealed by “sophisticated and varied techniques”.

Another one of the most famous rogue traders is Nick Leeson, who was a derivatives trader at the Singapore office of Britain’s Barings Bank. The $1.3 billion losses made by Leeson in 1995 eventually bankrupted the 233-year-old Barings Bank.