The determinants of intermediation margins in Islamic and conventional banks
Authors: Bougatef Khemaies , Korbi Fakhri 
Published: May 2018

Purpose
The distinctive feature of Islamic financial intermediation is its foundation on profit-and-loss sharing which reinforces solidarity and fraternity between partners. Thus, the bank margin and its determinants may differ between Islamic and conventional banks (CBs). The purpose of this paper is to empirically assess the main factors that explain the bank margin in a panel of Islamic and CBs operating in the Middle East and North Africa (MENA) region. This study will permit to identify the common and the specific determinants of the intermediation margins in dual banking systems.

Design/methodology/approach
The authors use a dynamic panel approach. The empirical analysis is carried out for a sample of 50 Islamic banks (IBs) and 126 CBs from 14 MENA countries.

Findings
The results reveal that net profit margins of IBs may be explained for the most part by risk aversion, inefficiency, diversification and economic conditions. With regard to CBs, their margins depend positively on market concentration and risk aversion and negatively on specialization, diversification, inefficiency and liquidity.

Practical implications
The significant impact of the degree of diversification on margins suggests that any policy analysis of the pricing behavior of banks should rely on its whole output. The high levels of margins in Islamic and CBs based in the MENA region may represent an obstacle to these countries to pursue their development process. Thus, policy makers in these countries should consolidate the role of capital markets and nonbanking financial institutions to provide alternative sources of funding and stimulate more competition.

Social implications
The positive relationship between concentration and net interest margins requires that policy makers should create competitive conditions if they want to lower the social cost of financial intermediation. The creation of competitive conditions may be achieved through encouraging the establishment of new domestic banks or the penetration of foreign banks.

Originality/value
The present study aims to contribute to the existing literature on the determinants of bank margins in three ways. First, the authors identify the factors that most explain bank margins for both conventional and IBs. The majority of previous studies examine the determinants of the profitability or the overall performance of banks and in particular conventional ones. Second, this paper employs two generalized method of moments (GMM) approaches introduced by Arellano and Bover (1995) and Arellano and Bond (1991). It differs from Hutapea and Kasri (2010) who employed the co-integration technique to examine the long-run relationship between Islamic and CB margins and their determinants in Indonesia. Third, unlike previous studies focusing on MENA region that use a small number of countries and a short sample period, the period of study covers 16 years from 1999 to 2014 and a large sample of countries (14 countries). This paper differs from Lee and Isa (2017) who applied the dynamic two-step GMM estimator technique introduced by Arellano and Bond (1991) to study the determinants of intermediation margins of Islamic and CBs located in Malaysia.