Financial inclusion - underground economy nexus: Does institutional quality matter? Evidence from OIC member countries

The growth of the underground economy within the OIC nations has alarmed many states to find solutions because it limits the development of the region by directly or indirectly influencing policies. The study's objectives are to examine the impact of financial inclusion on the underground economy within a dual banking system, then measure the role of institutional development on the underground economy, and lastly examine the factors influencing the underground economy, particularly in the OIC region. The study applies the fixed effects methodology to panel data from 49 countries for over 16 years, from 2002 to 2018. The findings depict that there is a negative relationship between the underground economy and financial inclusion between both Islamic and conventional banks. There is a positive relationship between institutional quality and the underground economy in the presence of Islamic banks and a negative relationship in the presence of conventional banks. Furthermore, as the size of the underground economy increases as taxes increase in the presence of both Islamic and conventional banks, the real effective exchange rate and GDP annual growth are positive in the presence of Islamic banks, caused by the small market share of Islamic banks within the OIC compared to conventional banks, and negative in the presence of conventional banks. Thus, the study suggests that policymakers need to consider investing more in Islamic institutions to increase the impact of financial inclusion and institutional quality on the underground economy.