Social mood and behavior of investors; evidence of herd behavior of investors in the religious months

Studies show religion is effective factor in forming social mood. Therefore, the impact of religion on behavioral bias affected by social mood can be studied. This study is an ex-post facto research that Using observed data tests possibility of herd behavior in religious months, consist of Muharram, Ramadan, and Zul-Hijjah, in Iranian capital market. After studying 1206 days of Daily trade in Tehran Stock Exchange during 1989-1993 (Solar Hijri-Iranian calendar), results show possibility of herd behavior in religious months more than other months of the year. Between religious month, Ramadan has the greatest impact of forming herd behavior. Also, the theories point out market performance and trading volume affect herd behavior. Accordingly, using robustness tests, this study investigates possibility of herd behavior affected by market performance and trading volume. However, there was no certain pattern. These results make contributions to the literature on the effects of social norm studies on markets, herding in stock market, and Islamic finance studies in particular.