«ΣΠΟΥΔΑΙ», Τόμος 48, Τεύχος 1ο-4ο, Πανεπιστήμιο Πειραιώς / «SPOUDAI»,Vol. 48, No 1-4, University of Piraeus THE INFLUENCE OF FOREIGN MARKETS ON THE ATHENS STOCK EXCHANGE By Alexandros E. Milionis, Demetrios Moschos and Manolis Xanthakis University of Athens, Department of Economics Abstract This paper examines the influence of Standard and Poor 500 (SP-500) and Financial Times 100 (FT-100) stock price indices on the General Index (GEN) of the Athens Stock Exchange (ASE), which belongs to the European Emerging Markets. The methodological approach is based mainly on multivar- iate Box-Jenkins modelling. The results indicate that there is statistically significant causal effect of small magnitude from SP-500 on GEN and a weak but also statistically significant correlation between FT-100 and GEN. The explanatory power of both the causal effect and the correlation on GEN is smaller as compared with that of its own past history. The existence of substantial within — series correlation in GEN, but primarily its particular pattern, entails the rejection of the hypothesis, of weak-form market efficiency for ASE. However, ASE is informationally efficient in terms of the time required for the assimilation of new information from foreign markets. (JEL: G14, G15, C22, C32). 1. Introduction Co-movement in stock prices in different countries is of interest for several reasons. Primarily it is of interest to investors who wish to obtain the maximum possible rate of return on their investment for a given risk, by properly allocating their investment portfolios. It is also of interest to the economic forecasters and policy makers as the covariation of stock prices: (a) can be considered as an alternative measure of financial integration, the latter being customarily assessed in terms of dispersion of interest rates between markets; (b) indirectly affect consumption and investment expenditures. Since the establishment of the theoretical framework of modern financial theory (Markowitz, 1952; Sharpe, 1964; Lintner, 1965) there have been numer- ous studies which have examined the covariation in the stock indices of most of