This paper studies the impact of the stock market continuity on the returns volatility and on the
market efficiency in the Casablanca Stock Exchange. For the most active stocks, the trading mechanism
used is the continuous market which is preceded by a call market pre opening session. Results
obtained concerning return volatility and efficiency under the two trading mechanisms show that the
continuous market returns are more volatile than the call market returns and 50% of stocks studied
show independence between variations.
