Since the late 1980s national authorities from the G-10 and some other countries have engaged in increasingly complex national and international regulatory reforms in the banking sector (Simmons 1999; Lütz 2000). The aim of regulatory activity, a large part of which concentrates on bank capital-asset ratios (CAR), has been to mitigate bank solvency problems that may destabilize national and international financial systems. The motivation behind the proliferation of regulatory activity is found in the presumption that the banks, if left alone, would select to remain undercapitalized relative to the socially optimal level.
In this paper we attempt to explicitly evaluate the validity of this popular presumption. We first construct a model that explains how banks select their capital-asset ratios. The model explains why and how competition among banks can support high capital-asset ratios. It suggests that "market discipline" (competitive forces) can not only assist the implementation of capital adequacy regulations but may even substitute for such regulations.