Abstract

The informational efficiency is a topic that animated the debate between financial theorists. The richness and diversity of works that have attempted to study the efficiency reflect the great interest granted by the academic and professional community to this theme. The starting point for efficient market hypothesis is information. In fact, it is according to the nature of information (past, public or non-public) considered that the form of efficiency is determined. Eugene FAMA distinguishes between three forms of efficiency (weak form, semi-strong form, and strong form). The first two forms were generally validated by econometric tests. The third form remains controversial and difficult to verify. In Morocco, the issue of stock market efficiency is a current topic which deserves to be studied. Through this article, we set three main objectives: to test the informational efficiency of Casablanca Stock Exchange, to determine the elements affecting this efficiency and to propose measures to improve it.