“…The empirical study of Jawadi et al (2017) also show that commodity prices are responsive to M2 of the Fed since commodity prices respond immediately and positively to the expansionary monetary policy shocks. The interest rate variable used for capturing the unconventional period varies among the researchers due to the zero lower bond (ZLB), where some studies relied on the interest rate spread (Chen et al, 2016;Hammoudeh et al, 2015;Hanabusa, 2017) while others (Caraiani & Calin, 2020;Hafemann & Tillmann, 2017;Hájek & Horváth, 2018) preferred to use the shadow policy rates introduced either by Wu and Xia (2016) or by Krippner (2013).…”