The Impact of Basel III Capital Regulation on Profitability: A Hybrid Model

Abstract

This research examined the impact of Basel III capital regulation (BCR) on profitability (P) using a sample of 25 commercial banks in Lebanon over the period 2012–2017. BCR is measured using the capital adequacy ratio (CAR) and the common equity tier one ratio (CET1 ratio), P is measured using two ratios: ROAA and ROAE. To analyze the data, we constructed a hybrid model based on three statistical approaches. First, we modelled the dual impact of BCR and P using probabilistic inference in the framework of Bayesian Belief Network formalism (BBN). Second, to highlight more about the correlation between BCR and P, we used the Spearman correlation test as a nonparametric approach. Third, to study the simultaneous effect of the BCR ratio on Profitability we apply multivariate regression analysis. By analyzing the probabilistic inference for the first approach, we concluded that there is an effect from BCR on P. When we investigated more if this effect is significance using the Spearman correlation test and the multivariate regression analysis, we concluded that that the impact of BCR on P is only found between CAR and ROAA and this regression relationship is weak because only 24.3% of the changes in ROAA variance is explained by CAR.