An alleged rogue trader accused of losing Swiss banking giant UBS about $2.3 billion is "sorry beyond words," his lawyer said Thursday, as a judge ordered him to be held in jail until a hearing next month.

Kweku Adoboli, 31, is charged with four offenses of fraud and false accounting dating back to 2008 and accused of racking up losses in authorized trades. His arrest a week ago has heaped pressure on UBS Chief Executive Oswald Gruebel and stoked speculation that the bank could get rid of its investment banking operations.

At a court hearing in London, prosecuting lawyer David Levy added a new fraud offense to the three previous charges laid against Adoboli, and confirmed that authorities had revised upward the amount allegedly gambled away by the trader to around $2.3 billion. A previous hearing was told the trader was accused of losing $2 billion.

Patrick Gibbs, defending Adoboli, said his client — who wore a gray suit, white shirt and dark blue tie — was truly sorry for his actions.

"He is sorry beyond words for what has happened here, he went to UBS and told them what he had done, and stands now appalled at the scale of the consequences of his disastrous miscalculations," Gibbs said.

Adoboli, who appeared confident and nodded in acknowledgment to a handful of supporters attending the hearing, spoke only to confirm his name, birth date and address. He did not enter any pleas to the charges.