Abdelkader Aguir University of Sousse, Faculty of Economics & Management, Lab MOFID/Laboratoire ESPI2R (Groupe ESPI)   3 rue boris vian App18 SAINT-MARTIN-D'HÈRES, France 38400 France   a.aguir@groupe-espi.fr             JEL Areas: E : Macroeconomics and Monetary Economics E5 : Monetary Policy, Central Banking, and the Supply of Money and Credit: General