本文放松了Easley和O’Hara信息成本为0的假设,在他们的信息结构模型的理论框架下,构建了一个引入信息成本因素的信息结构模型。从信息结构的四个方面:信息成本、信息风险、信息披露的质量和先验信息质量研究了信息结构与股权融资成本之间的关系,得出了四个推论,从而拓展了信息结构模型。在进一步的实证研究中,选取市场微观结构理论中的逆向选择成本、知情交易概率—PIN分别作为信息成本和信息风险的衡量指标,研究发现:信息成本与股权融资成本之间呈倒‘U’型曲线关系;信息风险越高的股票股权融资成本越高;信息披露质量越高的公司,股权融资成本越低;先验信息质量越高,股权融资成本越低;从而对推论进行了有效验证。本文与Easley和O’Hara最大不同在于引入了信息成本因素,并且用实证方法对推论进行了验证,具有一定的开创性。 This paper relaxes the hypothesis that the information cost of Easley and O’Hara is zero and constructs an information structure model that introduces the information cost under the theoretical framework of their information structure model. From four aspects of information structure: information cost, information risk, the quality of information disclosure and the quality of prior information, the relationship between information structure and equity financing cost has been studied, and four inferences have been drawn, so as to expand the information structure model. In the further empirical study, we choose the adverse selection cost and the probability of informed transaction in market microstructure as the measure of information cost and information risk, respectively. The results show that the information cost and equity financing cost are inverted U ’ Type curve; the higher the information risk is, the higher the cost of stock equity financing; the higher the quality of information disclosure, the lower the cost of equity financing; the higher the a priori information quality, the lower the cost of equity financing; . The main difference between this paper and Easley and O’Hara lies in introducing the information cost factor, and verifying the corollary with the empirical method, which is of some groundbreaking nature.