Oswald Gruebel, who led both of Switzerland’s two biggest banks during his career, criticised negative interest rates and argued they’d lead to a further decline of the country’s financial sector. "Negative interest rates are crazy. That means money is not worth anything any more," Mr Gruebel said in an interview with Swiss newspaper <em>NZZ am Sonntag</em>. "As long as we have negative interest rates, the financial industry will continue to shrink." Mr Gruebel served as Credit Suisse chief executive from 2004 to 2007 and as UBS Group’s top executive from 2009 to 2011. The Swiss National Bank has used negative interest rates since 2015 to rein in an appreciation of the franc, arguing the policy — together with a pledge to intervene in currency markets — is crucial to protect the economy. Yet banks are suffering. Credit Suisse plans to impose charges on more wealthy clients as it prepares to spread the pain of sub-zero rates, <em>Bloomberg</em> reported in September. Policymakers are aware of the burden. At their last meeting in September, they decided to offer banks additional relief by exempting a larger amount of their deposits from the charge. The move was seen as giving the central bank leeway to cut rates further if needed. In the interview, Mr Gruebel also addressed the <a href="http://Credit Suisse chief operating officer steps down over spying scandal">spying scandal</a> that has rocked the Swiss financial sector. He previously called for current Credit Suisse chief executive Tidjane Thiam to step down over a decision to hire private detectives to trail the former head of wealth management Iqbal Khan as he was about to defect to UBS. Credit Suisse chief operating officer Pierre-Olivier Bouee resigned and assumed responsibility for ordering the spying, which Credit Suisse said “resulted in severe reputational damage to the bank”. Mr Thiam, who has claimed he wasn’t aware, was cleared of any responsibility in the scandal in a report commissioned by the bank. Mr Gruebel argued Credit Suisse’s handling of the situation has hurt the standing of Switzerland as a banking hub. “Foreign media are bursting with glee,” he was quoted as saying. “In a business that above all requires expertise, there’s nothing worse than to look ridiculous.” Mr Gruebel resigned from his post at UBS in 2011 shortly after it was revealed that a trader had lost $2 billion (Dh7.34bn). He took the decision "to save the bank's reputation," he told <em>NZZ</em>. “The CEO must take responsibility. In such incidents, the boss cannot blame anyone, even if he did not know it.”