This paper develops a dynamic structural model of bank behaviour. Banks can vary their financing structure, business model and decide on rating solicitation, in the presence of costly debt, corporation tax, insolvency costs and convex adjustment costs. The model is then simulated to examine the impact of regulation on banks’ behaviour. A bail-in regime leads to reduced bank lending activity, while having little impact on bank insolvency rates. Stringent capital requirements reduce bank insolvency rates in a crisis period, while mitigating the reduction in lending activity due to an increased uptake in marginal investments. More lenient credit ratings are associated with increased bank failures. These findings offer wide-ranging implications for policy makers and the banking industry.