Investor Reaction to Market Surprises on the Istanbul Stock Exchange Investor Reaction to Market Surprises on the Istanbul Stock Exchange = stanbul Menkul K ymetler Borsas nda Piyasa Sürprizlerine Yat r mc Tepkisi

This paper examines the reaction of investors to the arrival of unexpected information on the Istanbul Stock Exchange. The empirical results suggest that the investor reaction following unexpected news on the ISE100 is consistent with Overreaction Hypothesis especially after unfavorable market surprises. Interestingly such pattern does not exist for ISE30 index which includes more liquid and informationally efficient securities. A possible implication of this study for investors is that employing a semi contrarian investment strategy of buying losers in ISE100 may generate superior returns. Moreover, results are supportive of the last regulation change of Capital Market Board of Turkey which mandates more disclosure regarding the trading of less liquid stocks with lower market capitalization.