بررسی عوامل موثر بر بازده غیر عادی کوتاه مدت شرکتهای تازه پذیرفته شده در بورس اوراق بهادار تهران

The lack of sufficient information about the past and present performance of newly accepted companies at Tehran Stock Exchange, uncertainty in future perspective of these new companies, lack of precedent transactions for the stocks of these companies and also existence of information asymmetry between the suppliers of new stock and external investors have caused confusion in the process of pricing new stocks in the stock exchange. So in this situation it will be more important to recognize those factors which affect the short-term return of the new listed companies at Tehran Stock Exchange.In this research, the short-term return of new stock and also those factors that affect the short- term return of new-listed companies at Tehran Stock Exchange were studied. The goal of this research was to identify whether the issuance of new stock at Tehran Stock Exchange would result in abnormal return in short-run.This research evaluates five hypotheses. In these hypotheses the size of company, ratio of book value to market value, issuance of major new stock, and return of market a month before entering into the stock and the kinds of industry are considered as independent variables and abnormal short-term return of new-listed companies is also considered as dependent variable. Evaluation of researcher’s hypotheses by means of regression and one factor analysis of variance between years 1381-85 showed that among the different factors, only the kind of industry affected abnormal short-term stock return.