【正文】 ing, what are possible causes of rational herd behavior, what success existing studies have had in identifying it, and what effect such behavior has on financial markets. In Section I, we discuss how imperfect information, concern for reputation, and pensation structures can cause herding. Intentional herding may be inefficient and is usually characterized by fragility and idiosyncrasy. It can lead to excess volatility and systemic Therefore, it is important to distinguish between true (intentional) and spurious (unintentional)herding. Furthermore, the causes of investor herding are crucial for determining policy responses for mitigating herd behavior. How does one empirically distinguish between informational, reputationbased, and pensationbased herding?One approach would be to examine whether the assumptions underlying some of the theories of herd behavior are satisfied. 5 A financial asset bought by one market player must be sold by , all market participants cannot be part of a “buying herd” or a “selling herd.” To examine herd behavior, one needs to find a group of participants that trade actively and act similarly. Such a group is more likely to herd if it is sufficiently homogenous (each member faces a similar decision problem), and each member can observe the trades of other members of the group. Also, such a homogenous group cannot be too large relative to the size of the market because in a large group (say one that holds 80 percent of the outstanding stock) both buyers and sellers are likely to be adequately represented. It is unlikely that investors observe each other’s holdings of an individual stock soon enough to change their own portfolios. There is therefore little possibility of intentional herding at the level of individual stocks. One is more likely to find herding at the level of investments in a group of stocks (stocks of firms in an industry or in a country) after the impact of fundamentals has been factored out. Manski (2020) provides an accessible survey of the state of empirical research on social interactions, and the difficulty of drawing inferences about the nature of an interaction process from observations on its outes. He argues that structural analysis of markets remains a subtle inferential problem and econometric methods do not—indeed cannot—resolve the basic identification problem. The data monly brought to bear to study such interactions has only limited power to distinguish among alternative plausible on market transactions and their prices can reveal only so much about the factors determining the choices of market participants. And given the data currently available, analysis of social interactions requires strong assumptions that diminish the credibility of the conclusions about behavior. 6 本科畢業(yè)論文外文翻譯 外文題目： Herd Behavior in Financial Market 出 處 IMF Staff Papers , 作 者： Sushil Bik