Conventional intermediation theories argue that imperfections in financial markets are raison d'etre for financial intermediaries such as banks. Islamic banks are no different from their conventional counterparts in this regard as they too perform similar intermediary functions. However, unlike their conventional counterparts, the principles of Islamic banks are different as they are operated on Shariah-based precepts of riba avoidance and risk sharing. In practice, however, Islamic banks are claimed to be likened to conventional banks, which raises concerns about possible convergence of these two banking systems over time.

This paper investigates the effects of sectoral diversification of loans and financing on the risk and the returns of banks in dual-banking systems. We employ the system GMM estimator on a unique panel data of 46 Islamic and 60 conventional banks from six countries over the period 2000-2015. Our findings reveal that sectoral diversification of loans and financing reduces the returns and increases the risk of both Islamic and conventional banks; the impact of sectoral diversification on returns varies across risk levels, with negative effects at low- and no effect at moderate- and high-risk levels; the difference between the impacts on Islamic and conventional banks across risk levels are marginal, and the adverse effects of sectoral diversification were exacerbated during the 2008 financial crisis. Expansion of loan and financing portfolios into new sectors has no impact on bank returns and risk in our sample. The findings may provide valuable implications for all stakeholders, regulators, and policymakers.

In theory, the cornerstones of Islamic finance are interest avoidance and risk-sharing. In practice, however, Islamic banks seem to be lacking both, particularly the latter. We investigate the interest rate impact on Islamic banks' three most-widely used types of financing instruments - i.e. sale-based, lease-based and risk-sharing-by employing the system GMM estimators on a unique panel data set of 77 Islamic banks from 13 countries over the period 2003-2017. We find that sale- and lease-based financing instruments are negatively correlated with the interest rate and that their exposure is amplified in more developed Islamic banking jurisdictions. Risk-sharing instruments, however, appear to be out of the interest rate domain of influence except in less developed Islamic banking jurisdictions, where the impact is positive. Additionally, the above effects on sale-based and risk-sharing instruments hold true only in the case of full-fledged Islamic banks and Islamic bank subsidiaries, respectively; the impact on lease-based instruments hold under all specifications. The findings imply that predominant use of sale- and lease-based financing instruments in their current form undermines the interest-free and risk-sharing essence of Islamic banking and runs the risk of converging with its conventional counterpart.

The issue of whether banks should diversify or focus their portfolios is theoretically and empirically open to debate. Traditional wisdom in banking argues that diversification can reduce risk and improve retums. The theory of corporate finance, however, contends that diversification increases earnings volatility, write-downs and write-offs, agency problems and inefficiency. While the former suggests that banks should be as diversified as possible, the latter recommends that banks should focus their activities. In an attempt to test these arguments, numerous empirical studies have been conducted - primarily on conventional banks in single-banking systems from developed economies and large emerging market countries. However, there is no consensus thus far as there is evidence supporting both arguments. In other words, no single strategy can be uniformly applied across banks from different countries ...

In theory, Risk Sharing-based Financing (RSF) is considered a corner stone of Islamic finance. It is argued to render Islamic banks more resilient to shocks. In practice, however, this feature of Islamic financial products is almost negligible. Instead, debt based instruments, with conventional like features, have overwhelmed the nascent industry. In addition, the framework of present-day economic, regulatory and financial reality inevitably exposes Islamic banks in dual banking systems to problems of conventional banks. This includes, but is not limited to, interest rate risk. Empirical evidence has, thus far, confirmed such exposures, despite Islamic banks' interest free operations. This study applies system GMM in modeling the determinants of RSF, and finds that RSF is insensitive to changes in interest rates. Hence, our results provide support to the "stability" view of risk sharing- based financing. This suggests RSF as the way forward for risk management at Islamic banks, in the absence of widely acceptable Shariah compliant hedging instruments. Further support to the stability view is given by evidence of counter cyclicality. Unlike debt-based lending that inflates artificial asset bubbles through credit expansion during the upswing of business cycles, RSF is negatively related to GDP growth. Our results also imply a significantly strong relationship between risk-sharing deposits and RSF. However, the pass-through of these deposits to RSF is economically low. Only about 40 percent of risk-sharing deposits are channeled to risk-sharing financing. This raises questions on the validity of the industry's claim that depositors accustomed to conventional banking shun away from risk sharing and signals potential for better balance sheet management at Islamic banks. Overall, our findings suggest that, on the one hand, Islamic banks can gain "independence" from conventional banks and interest rates through risk-sharing products, the potential for which is enormous. On the other hand, RSF could enable policy makers to improve systemic stability and restrain excessive credit expansion through its counter cyclical features.