The basic theory of bank regulation is that, left to their own devices, bankers would make banks too risky, so regulators and supervisors are there to make banks more boring. A bank is, roughly, a big pot of assets bought with depositors’ money; the bank owns essentially an option on those assets. If the assets go up, the bank gets a highly leveraged return; if the assets go down, the losses are largely the depositors’ (or the taxpayers’) problem. “Heads I win, tails you lose” … So banks have incentives to buy high-risk, high-return assets with as much leverage as possible, and risk-based capital regulation and prudential bank supervision counteract those incentives. The bankers — who own stock in their banks and get paid bonuses for making money — push for more risk and more volatility, and the bank supervisors push back.
