Swiss banking giant UBS said Thursday that one of its traders lost an estimated $2 billion through unauthorized transactions, which could result in a loss for its entire third quarter.
Police in London's financial district said they have arrested a 31-year-old man in connection with the massive loss. He was arrested at 3:30 a.m. on suspicion of abusing his position to commit fraud.
The unidentified trader reportedly worked in UBS's London equities division.
Shares of UBS sank on the Zurich exchange Thursday, at one point plummeting more than 8 percent.