The Effect of Foreign Investors on Security Markets: The Case of Istanbul Stock Exchange

The study aims at analyzing the effect of foreign portfolio investment on Istanbul Stock Exchange (ISE). ISE-100 index, price/earnings ratio, value of share trading and market capitalizion are studied as indicators related with ISE. Foreign portfolio investment is examined as two subgroups: purchases and sales. Unit root tests, cointegration analysis and causality tests are employed in the study, which covers the period of 1997-2007. The results show that there is a long-run relation (cointegration) between purchases and sales of foreign investors, and ISE-100 index, trading volume and market capitalizion. The purchases of foreign investors have a positive effect and the sales of foreign investors have a negative effect on these indicators, and their explanatory power is quite high.