Individual investors’ risk perceptions are affected by personality traits, socio-economic and demographic factors and psychological factors. All these factors, which are interacting with each other, do affect the investor’s risk perception concurrently. Behavioral financiers assert that effect of over confidence bias on investor’s behaviors can be observed on investors’ trading volume, trading frequency and portfolio diversification levels. According to this, over confidence of investors increases their trading volumes and trading frequencies but decreases their levels of portfolio diversifications. Especially in recent years increasing diversity of investors’ profile appears to be a parameter to be considered in interpretation of the terms of financial markets. The purpose of this study is to investigate the occurred differences in investors trading volume, trading frequencies and portfolio diversification levels according to their demographic and socio-economic factors. The study used real data about 31 individual investors who had realized the stock purchase- sale transactions in Istanbul Stock Exchange between 1st January 2007 to 31st December 2009. In this context, analyses of one way ANOVA and T-Test showed that trading volume, trading frequency and portfolio diversification levels change significantly according to investors’ socio-economic and demographic factors such as age, gender, marital status and monthly income