LONDON — A former UBS trader, Kweku M. Adoboli, pleaded not guilty on Monday to charges of fraud and false accounting that led to a $2.3 billion trading loss at UBS last year.
Standing in a glass-walled box in a London court, Mr. Adoboli, 31, pleaded not guilty to each of the four counts. He faces up to 10 years in prison if found guilty of the two counts of falsifying accounts and two counts of fraud by abuse of position.
The judge, Alistair McCreath, sent Mr. Adoboli back into custody and said the trial would start Sept. 3. Given the “magnitude” of the case, with a vast amount of material and witnesses, “it’s unlikely to try before that,” the judge said. The trial is expected to last as long as eight weeks.
A spokesman for UBS declined to comment, saying that during active criminal proceedings, “English criminal law limits what we can say about this incident.”
Paul Garlick, Mr. Adoboli’s lawyer, said he expected to enter an application for bail “in the near future.”
Mr. Adoboli was arrested Sept. 15 on suspicion of fraud after UBS alerted the police. The bank has said it lost $2.3 billion as a result of unauthorized trades in equity index futures and claimed that Mr. Adoboli had masked those activities from internal controls with fictitious trades.
In a surprise step in December, Mr. Adoboli fired his lawyers at Kingsley Napley, the firm that previously represented Nick Leeson, the rogue trader blamed for the collapse of the British bank Barings in 1995. His lawyer had told a court in September that Mr. Adoboli was “sorry beyond words for what had happened” at UBS. Mr. Adoboli switched to another law firm and then asked the court for more time to enter a plea.
The trading scandal shook UBS and prompted the resignation of its chief executive, Oswald J. Grübel.
While UBS, based in Zurich, has completed an internal investigation into the trading loss, a separate inquiry by the Financial Services Authority, the British regulatory agency, and the Swiss financial watchdog is continuing. The F.S.A. has hired the accounting firm KPMG to help.
The bank’s internal investigation showed that while its risk controls had picked up something unusual and red flags had been raised, those in charge had failed to investigate them sufficiently. UBS said in October that the co-heads of the equity division in London, where the trades occurred, had resigned.
“We have to be straight with ourselves,” Sergio P. Ermotti, the chief executive, said then. “In no circumstances should something like this ever occur.”