A Practical Approach To Capital Structure For Banks

Like U.S. companies in many industries. American's bank's attention to capital structure is reflected in their high level of stock repurchases in recent years. But, if banks are responding to some of the same economic forces that are driving industrial firms to shed excess capital, there are some important differences between banks and industrials that complicate the process of establishing appropriate capital levels for banks. The most important difference comes from regulation. Since the implementation by FDICIA of risk based capital guidelines in the early 1990s, the capital ratios of U.S. banks have increased substantially. In fact, most U.S. banks today carry considerably more capital than is required by the regulators. This tendency to exceed regulatory capital levels is especially pronounced for smaller institutions, which can in turn be explained by the riskier profile of smaller banks: While such banks have the highest proportion of the lowest‐risk assets (such as cash, mortgages, and marketable securities), they also have a much greater degree of concentration (and co‐variance) among their riskier assets. This article recommends using a quantitative economic approach (such as a RAROC model) to generate a lower bound on the amount of necessary capital. This estimate can then be translated into a target capital structure by taking account of a variety of practical, qualitative considerations, including banks' preference to maintain capital levels that provide a comfortable margin above bank regulators' “well capitalized” levels. Although such considerations will vary in importance from one bank to another, they will generally include management's risk tolerance, regulatory constraints, market pressures (as reflected in peer group capital levels), the bank's prospects and investment plans, and, for larger banks, rating agency requirements.