UBS lost billions of dollars during the global economic crisis and the confidence of many investors during a long tax row with Washington.
The bank has faced public pressure from taxpayers who have had to shoulder the bill for its rescue.
Kaspar Villiger, who took over as chairman 19 months ago, apologised for “difficult times” as he presented a transparency report on mistakes made by previous management.
The bank has recovered Sfr70m (£45.9m) from former directors or managers who either waived or repaid bonuses or salaries.
But Villiger voiced doubts that legal action could have got back more than that and said trying to recover losses through the law would be costly, attract negative publicity and would be distracting.
He also said suits against its former staff would reflect negatively in class-action lawsuits being taken in the US against UBS and previous management, because US lawyers see such action as an admission of guilt.
Villiger added that none of UBS’s major shareholders indicated they intend to pursue legal action of their own, and that such a step would only weaken the bank’s share price.