Trader pleads not guilty in $2.3B loss

LONDON, Jan. 30 (UPI) -- Former UBS trader Kwaku Adoboli, charged with fraudulent trades that lost $2.3 billion, pleaded not guilty in a London court Monday.

Allegedly, the fraud took place between January and September 2011. It is thought to be the largest sum ever lost in a case of unauthorized trading at an investment bank, CNN reported.

Last year, his attorney said Adoboli was "sorry beyond words." He is charged with abusing his position and accounting fraud.

UBS Chief Executive Officer Oswald Gruebel resigned two days after Adoboli was arrested, a move Chairman Kaspar Villiger said was "testimony to his uncompromising principles and integrity."

In October, the bank said the co-leaders of the equity division where Adoboli worked had resigned. An internal bank investigation concluded that there were warning signs that something was amiss, but nobody thoroughly looked into the matter, The New York Times reported.

"We have to be straight with ourselves. In no circumstances should something like this ever occur," said the bank's new CEO, Sergio Ermotti.

A trial, which is expected to last two months, was scheduled to begin Sept. 3, the Times said.