Market Power and Efficiency in the Iranian Banking Industry

This paper explores the nature of the causal relationship between market power and cost efficiency for a sample of banks operating in the Iranian banking industry over the period 2002–2014. In particular, a bootstrap panel Granger causality approach is used to test the “quiet life”, “banking specificities”, and “efficient-structure” hypotheses, accounting for both slope heterogeneity and cross-sectional dependence. The results indicate that, on average, banks’ market power (measured by the efficiency-adjusted Lerner index) has steadily declined over the study period, while cost efficiency (measured by the SFA approach) has improved over the period. Furthermore, the results of the causality analysis suggest that there is a negative unidirectional causality running from market power to cost efficiency for 56.25% of banks, providing evidence to support the “quiet life” hypothesis, according to which banks with greater market power would be less cost-efficient. Such a result clearly rejects the “banking specificities” and “efficient-structure” hypotheses which predict a positive Granger causality in the same and opposite directions, respectively. These results are robust to the use of an alternative Granger non-causality procedure.