The Optimal Capital Structure of Banks: Balancing Deposit Insurance, Capital Requirements and Tax-Advantaged Debt

The capital structure and regulation of financial intermediaries is an important topic for practitioners, regulators and academic researchers. In general, theory predicts that firms choose their capital structures by balancing the benefits of debt (e.g., tax and agency benefits) against its costs (e.g., bankruptcy costs). However, when traditional corporate finance models have been applied to insured financial institutions, the results have generally predicted corner solutions (all equity or all debt) to the capital structure problem. This paper studies the impact and interaction of deposit insurance, capital requirements and tax benefits on a bankÇs choice of optimal capital structure. Using a contingent claims model to value the firm and its associated claims, we find that there exists an interior optimal capital ratio in the presence of deposit insurance, taxes and a minimum fixed capital standard. Banks voluntarily choose to maintain capital in excess of the minimum required in order to balance the risks of insolvency (especially the loss of future tax benefits) against the benefits of additional debt. Because we derive a closed- form solution, our model provides useful insights on several current policy debates including revisions to the regulatory framework for GSEs, tax policy in general and the tax exemption for credit unions.

Interbank Markets under Currency Boards

This paper analyzes interbank markets under currency boards. Under such an environment, problematic endogeneity issues common to other monetary regimes do not arise. Using daily data from the interbank markets in Bulgaria and Lithuania we show, that contrary to the existing literature, overnight interest rates tend to decrease towards the end of the reserve holding period. Empirical results are supported by a finite horizon heterogeneous agents model showing that interest rates tend to decrease in the case of excess aggregate reserves in the banking system. Results contrast with Quir'os and Mendiz'abal (2006) who find that interest rates should be increasing regardless of the outstanding aggregate liquidity in the market. We also show that responsiveness of banks to interest rate changes diminishes as the end of reserve holding period approaches. Under certain circumstances this could lead to multiple equilibria with increasing or decreasing interest rates.