Switzerland’s UBS – which has made more writedowns during the credit crisis than any other European bank – has appointed a new chief executive.The move should placated angry investors, who have seen the value of their shares plummet. He is Oswald Gruebel has come out of retirement to take the job. His claim to fame is that he masterminded a turnaround of UBS’s arch rival Credit Suisse. Gruebel said: “I believe in a strong UBS and in a strong Credit Suisse. We need two strong big banks (in Switzerland). I just started today. It will take several years to bring UBS back to the level of profitability the bank is used to.” He will replace Marcel Rohner who has resigned after just 18 months in the job. Rohner inherited a mess. He was named CEO just before the subprime meltdown in June 2007. He leaves one week after UBS settled US criminal charges by admitting it helped American clients dodge tax. The new boss called the job “a fascinating yet formidable challenge” and warned UBS staff to of more job cuts.