Bank competition, concentration and financial stability in the Turkish banking industry

This paper analyzes the impact of competition and concentration on bank stability in the Turkish banking industry over the period 2002-2012. The Boone indicator and the efficiency-adjusted Lerner index are used as proxies for competition, while the non-performing loans (NPL) ratio and Z-scores are used as proxies for bank stability. The main results indicate that competition is negatively related to the NPL ratio but positively related to the Z-score. The results further indicate that greater concentration has a positive impact on the NPL and a negative impact on the Z-score. We also use a quadratic term of the competition measures to capture a possible non-linear relationship between competition and stability. The results show that the coefficient of the quadratic term is negative for the NPL model and positive for the Z-score model. Overall, our findings provide support for the competition-fragility view.