Evaluation of Market Efficiency and Trading Behavior of Investors: Evidence From Borsa Istanbul

After the financial crisis of 2007-08, debates on structures and characteristics of financial markets have become the subject of much concern in both industry and academia. One of the most debated issues related to financial markets is whether they are efficient or not. With an intent to enter into discussions, this paper evaluates the market efficiency by using individual and institutional trade data from a specific stock exchange, namely Borsa Istanbul. To do so, we first form several measures of market efficiency through daily investor data covering five years. By using these measures, we show that there is a negative relationship between market efficiency and turnover. That is, the more efficient the market, the lower the turnover. This result contributes to the debate of irrationality of investor behavior. The data also suggests that the efficiency in Borsa Istanbul has been increasing after the crisis, showing that the effect of the crisis has been vanishing as time passes.