Introduction

The relationship between monetary policy and the real economy is identified through the influence of monetary transmission channels on macroeconomic variables especially economic growth, inflation and investment. The rule is simple, the more monetary policy affects the economy, the more effective it is. In other words, the effectiveness of monetary authorities’ decisions supposes the existence of a relationship between a set of monetary policy instruments, especially the policy rate, and macroeconomic performances through different transmission channels. Main channels through which monetary policy could impact economic activities are interest rate; money supply; bank credit; exchange rate; asset price and expectation channel (Bernanke and Gertler, 1995; Taylor, 1995, Mishkin, 1996Taylor, 1995, Mishkin, 1996). Recent studies have focused on some topics related to transmission channels like the effect of the financial crisis, unconventional monetary policy and capital inflows in emerging economies (Mishkin, 2009; Borio and Zhu, 2012; Cevik and Teksoz, 2012; Chandra and Unsal, 2012; Kohlscheen and Miyajima, 2015). Besides, after the development of Islamic finance in the 2000th, largely through the rapid expansion of Islamic banks, the effectiveness of monetary transmission mechanism (MTM) was challenged for the countries where Islamic banks are present. In these countries, in which a dual monetary system is emerging, a growing number of empirical studies examined the monetary transmission through Islamic bank channels (Zaheer et al., 2013; Ergeç and Arslan, 2013, Majid and Hasin, 2014; Akhatova et al., 2016; Zulkhibri and Sukmana, 2017). In reference to Sharia rules, Islamic banks institutions are free interest rate and fundamentally different from conventional banks. The differences mostly well-known through the principles of Sharia are based mainly on profit and loss sharing (PLS) principle and asset backing principle. Applying both principles on banking intermediation make assets financing and their pricing close to real economy. Nonetheless, given that debt financing contract, being the main Islamic banking asset, is quite similar to conventional credit, the conduct of monetary policy through interest rate instrument is also expected to influence Islamic banks financing. In fact, in most countries where Islamic banks operate, monetary policy uses interest rate instrument of monetary market regulation as a benchmark of credit financing rate. Besides, in dual financial system, the presence of strongly competitive conventional banks, the inexistence of benchmark pricing of Islamic bank products and the underdevelopment of Islamic money markets,1 make Islamic banks behaviour, in term of debt financing, heavily influenced by monetary policy shocks and conventional bank activity. On the other side, given this incompatible environment with their ethical background, the presence of Islamic banks is likely to limit the ability of monetary policy to influence their financing debt volume making Islamic banking channel less effective despite its dependence on interest rate. In fact, Islamic banks, mainly through the use of profit sharing investment accounts (PSIA), seek to maintain debt financing level outside the influence of conventional monetary policy and to mitigate the undesirable effect of interest rate changes. The Sharia compliance of PSIA as loss absorbent product based on PLS principle with different maturities and currencies explains its importance to play multiples roles.