If they could not calculate the risk, they should not have allowed the institutions under their supervision to undertake them. The risk models of the banks were based on the assumption that the system is stable. But, contrary to market fundamentalist beliefs, the stability of financial markets is not assured; it has to be actively maintained by the authorities. By relying on the risk calculations of the market participants, the regulators pulled up the anchor and unleashed a period of uncontrolled credit expansion. (New York Review of Books)