Islamic banking finance and private sector investment in dual banking systems: the impact of institutional quality

Purpose - This study aims to examine the role of Islamic Banking (IB) finance in promoting private sector investment within dual banking systems, with particular attention to the impact of institutional quality. Design/methodology/approach - Using panel data from 26 countries with dual banking systems over the 2004–2022 period, this study uses the system-GMM estimator to analyze the interaction between private investment, IB finance and institutional quality, using both aggregated and disaggregated institutional quality indicators. Findings - The results indicate that the direct effect of IB finance on private investment is generally limited across the sample. However, institutional quality, while showing a negative standalone effect, plays a pivotal role when considered interactively with IB finance. This study demonstrates that when both IB finance and institutional quality reach certain threshold levels, they exhibit a complementary relationship that significantly enhances private sector investment. The thresholds and key economic factors that influence private investment in the studied countries are estimated, providing valuable policy implications. Originality/value - This research provides new insights into the interplay between IB finance and institutional quality, emphasizing that the effectiveness of IB finance is conditional upon strong institutional frameworks. Unlike previous studies, the work redefines the finance-growth nexus in dual banking systems, demonstrating that institutional improvements are essential to unlocking the full potential of IB finance.