Does the Egyptian Stock Exchange Follow a Random Walk? An Empirical Analysis Evolving and Relative Efficiency of MENA Exchanges: Evidence from Rolling Joint Variance Ratio Tests Modelling Conditional Volatility and Downside Risk for Istanbul Stock Exchange DCCs among Sector Indexes and Dynamic Causality between Foreign Exchange and Equity Sector Volatility: Evidence from Egypt Bank-based Financial Development and Economic Growth: Time-varying causality analysis for Egypt