Firstly, I am writing about the potential to do harm. Secondly, banking is arguably at least as ubiquitous in global society as the other categories combined. Thirdly, the issue of incentives is more central to the risks banking poses than in the other fields. Fourthly, banking risk is more correlated, globally, than in the other cases.

The recent housing debacle was fundamentally a banking issue: irresponsible real-estate dealing could not have happened, to any extent, without irresponsible banking.