Josef Ackermann, the head of Deutsche Bank, combines a silky manner with blunt words. When the German government set up a bail-out fund to stabilize the country’s banking system, he said he would be “ashamed” to use it. When Europe and the IMF bailed out Greece, Mr. Ackermann said he doubted it would pay back the loans. And when regulators and economists say that big banks should be broken up, with “casino” investment banks split off from “utility” retail banks, Mr. Ackermann retorts that “smaller banks will not make us safer.”