Sergio Ermotti has been named as interim CEO effective immediately, a bank statement said, nine days after the arrest of a trader accused of a $2.3 billion fraud at UBS.

While the board “regrets” Gruebel’s decision UBS Chairman Kaspar Villiger said in the statement Gruebel “feels that it is his duty to assume responsibility for the recent unauthorised trading incident.”

Villiger praised Gruebel for “his uncompromising principles and integrity”, and acknowledged that during his tenure “he achieved an impressive turnaround and strengthened UBS fundamentally.”

The board also said it would “fully support” the independent investigation into the rogue trading and would ensure that “mitigating measures” were implement to prevent such incidents from recurring.

Kweku Adoboli, 31, the trader accused of the massive fraud at UBS’ London offices, is “sorry beyond words” over the losses, his lawyer said Thursday, as a court remanded him in custody for another month.