Regulatory Optimal Bank Size (Report‪)‬

Abstract This paper presents a study of potential outcomes of bank growth. Banks grow by expanding market presence within the geographic region within which they are domiciled and by expanding presence into other regions via new implantations. Growth leads to improved diversification, but also results in an increase in the risk of catastrophe that a bank's failure may engender. The conclusion is that there will exist a threshold size of bank at which the rate of growth in its systemic risk exceeds the rate of decline in its risk of insolvency. An empirical study of US bank call report data provides results that are consistent with the theory presented in the first part of the paper. Keywords Banks. Systemic risk. Diversification. Optimal size