Swiss bank UBS chief executive Oswald Gruebel has resigned over a $2.3 billion rogue trading loss, the bank said Saturday.

The move ends days of speculation about whether Gruebel could retain his position following the latest scandal to hit Switzerland's biggest bank.

UBS Europe chief Sergio P. Ermotti will take over immediately as interim chief executive until Gruebel's replacement is appointed, the bank said in a statement.

UBS's president Kaspar Villiger said the board regretted Gruebel's decision to resign but had decided to accept it.

"Oswald Gruebel feels that it is his duty to assume responsibility for the recent unauthorized trading incident," Villiger was quoted as saying in the statement. "It is testimony to his uncompromising principles and integrity."

London-based UBS trader Kweku Adoboli was arrested last week and charged with fraud and false accounting for the $2.3 billion loss. A judge ordered him Thursday to be held in jail until a hearing next month.

Villiger said Gruebel, who was brought in more than two years ago to help revive the fortunes of the Zurich-based bank, had achieved "an impressive turnaround and strengthened UBS fundamentally."

"He steps down having helped make UBS one of the world's best capitalized banks," Villiger added.

The announcement also noted that the board, which met in Singapore this week, would seek to put in place measures to prevent a similar rogue trading loss from recurring.