A capital adequacy framework for Islamic banks: the need to reconcile depositors' risk aversion with managers' risk taking

Conceptually, an Islamic bank has an equity-based capital structure, dominated by shareholders' equity and investment deposits based on profit and loss sharing (PLS). There is no need for capital adequacy regulations if the Islamic banks are structured as pure PLS-based organizations. However, because of informational asymmetry and risk aversion by investors, there currently exist fixed claim liabilities on the Islamic banking balance sheets. This necessitates the imposition of capital adequacy requirements, which aim at maintaining systemic stability by achieving two fundamental objectives. First, capital regulations should protect risk-averse (assumed unsophisticated) depositors. This requires a minimum equity capital cushion and an optimal assets-liabilities composition. Second, capital regulations should give the right incentives to shareholders to promote prudent behaviour by the banks. This requires analysis of the effect of financial participation by shareholders on Pareto optimality, and analysis of potential behaviour by shareholders when facing financial uncertainty. This paper combines modern banking theory and principal-agent analysis to develop a framework for an optimal capital structure for Islamic banks. The proposed capital regulation includes a minimum risk-based equity capital cushion (as required under the Basel Accord), a prudent assets-liabilities (capital) structure (i.e. appropriate proportions of PLS- and non-PLS-based assets and liabilities) and a minimum 'financial participation' requirement. It is inferred from the analysis that such capital adequacy requirements will improve the soundness of current Islamic banking practice, thus paving the way for the wider use of PLS by Islamic banks in the long run.