摘要：Numerous studies in different capital markets have shown that stock prices in initial public offerings change after a very short time, resulting in significant and unusual returns, which are referred to as underpricing of initial public offerings. Considering that previous studies, which are mainly based on the theory of information asymmetry and behavioral biases, have considered various and sometimes contradictory reasons as the cause of this phenomenon, this study aims to provide a comprehensive model of the factors explaining this abnormal return. Also, the role of accounting information in explaining this phenomenon has been investigated. To discover these factors, the researcher has studied the subject literature extensively, and using the qualitative method of theme analysis and interviewing experts to extract their opinions, has extracted repetitive patterns among the comments and by classifying them has developed a comprehensive model of factors affecting stock price in initial public offerings. In the model presented in this research, four factors of shortcomings of the initial supply process, fundamental factors, behavioral aspects and information content in the initial public offerings lead to underpricing in such a way that by intervening of regulatory bodies in the supply and demand mechanism pricing errors occur and fundamental factors are not reflected in offering prices. Investors' behavioral aspects and insufficient accounting information content exacerbate this. According to the research findings, those shareholders who analyze the available information, especially accounting information, can gain abnormal returns. Also, the need to provide prospective accounting information in an initial public offering to determine the real share price leads to an increase in accounting information content.
关键词：Underpricing in initial public offerings;information asymmetry;behavioral biases;accounting information content
