Capital Adequacy in Conventional Versus Islamic Banks According to Basel III and Islamic Accounting Standards and Its Impact on Financial Stability: Empirical Evidence from the Kingdom of Saudi Arabia

This study aims to compare capital adequacy and financial stability in Islamic and conventional Saudi banks and investigate the impact of capital adequacy on the financial stability of a bank. Our study uses the annual data of five conventional banks and four Islamic banks listed on the Saudi Stock Exchange for the period 2016–2020. The Z-score has been computed and used as the measure of the stability of listed Saudi Islamic and conventional banks for the period 2016–2020. This study uses ordinary least square regression to investigate the impact of capital adequacy on the financial stability of banks. The researchers adopt the development of research hypotheses in the light of the theory of stakeholders and the foundations of Islamic law. The findings indicated that, first, there are significant differences in the capital adequacy ratio between conventional and Islamic banks. This difference is due to the increase in the mean capital adequacy ratio of Islamic banks over conventional banks. Second, our result found significant differences in financial stability between conventional and Islamic banks. This difference is due to the increase in the mean of the Z-score for Islamic banks over conventional banks. Third, our result refers to significant negative impacts of capital adequacy ratio on financial stability. Our study applied to listed Saudi banks from 2016 to 2020. The empirical results of our study are very useful for supervisors, banks management, investors, bank customers, and policymakers. The results contribute to knowing the unexpected negative effects of increased capital adequacy and its negative impact on the bank’s profits and the threat to financial stability, in addition to knowing the main indicators of capital adequacy and financial stability for Islamic and conventional banks in a way that helps bank supervisors, policymakers, and investors in rationalizing. Their decisions are specific to both Islamic and conventional banks, in addition to identifying the factors that help to enhance the financial stability process. This study is among a few studies that provide empirical evidence for the claim that the increase in capital adequacy rates is always one of the positive indicators to achieve financial stability, in addition to the great role of Islamic banks in achieving this. The study found a rejection of the validity of this claim and reached unexpected results.