I recently watched a video regarding sociopathic and psychopathic personality disorders. One thing that stuck out to me is the part of the brain that connects behavior to punishment is not developed. In other words, punishment has little impact on them. Its why sociopaths released from prison have a ridiculously high reincarceration rate.
On the other hand these people are highly charming and fully rational. They tend to make great CEOs and are able to make major changes without any regard to suffering. I suspect CEOs of banks tend to get there for this reason.