“It’s hard to say definitively why anyone does anything, Joe, but here are a couple of big-picture thoughts. First, the world’s biggest banks are traded on the stock market, which means they make public declarations about how much they’ll earn and have investors who will punish them if they fall short. If the weight of those promises then trickles down to their employees, it can pressure them to hit targets or risk losing their jobs – and push them into doing things they otherwise wouldn’t. Second, the risk of billions of dollars in fines or sanctions might not actually be a strong enough disincentive for wrongdoing. After all, a bank would only face that outcome if it was caught out, investigated, and found guilty. So in the long run, it might be cheaper and more profitable for a bank to settle investigations using some of its ill-gotten gains than not to break the rules at all.”