Are bank shareholders enemies of regulators or a potential source of market discipline?

In moral hazard models, bank shareholders have incentives to transfer wealth from the deposit insurer - that is, maximize put option value - by pursuing riskier strategies. For safe banks with large charter value, however, the risk-taking incentive is outweighed by the possibility of losing charter value. Focusing on the relationship between Tobin's q and an ex ante measure of the failure probability, this paper develops a semi-parametric model for estimating the critical level of bank risk at which put option value starts outweighing charter value. From these estimates, we infer the prevalence of moral hazard. Examining publicly held bank holding companies (BHC) during the tumultuous 1986-1992 period, we find that shareholders' risk-taking incentives were confined to a small fraction of highly risky institutions. Furthermore, our analysis shows that the inflection point at which banks begin to tilt in favor of moral hazard increased substantially in 1993-2005. These findings are encouraging to bank regulators and legislators because they indicate that tighter capital rules and more rigorous supervision introduced by several legislative initiatives in the 1990s have helped squeeze a lot of the moral hazard incentives out of the banking system.