Abstract: As an important part of Chinas financial supplyside reform, stock market liberalization has significantly changed the characteristics of Chinas capital markets trader structure, which may have a profound impact on the selfinterest behavior of listed firms. Based on the institutional background of “ShanghaiHong Kong Stock Connect Program”, this paper shows that the stock market liberalization can inhibit corporate tax avoidance. Through the mechanism test, it is found that the stock market liberalization not only helps to improve corporate governance and suppress the executives incentives for tax avoidance and rentseeking, but also improves the corporate information quality and increases the cost of tax avoidance, thus leading to a reduction in corporate tax avoidance. Further research shows that this effect is more significant for firms in regions with low tax collection and management intensity. Accordingly, the conclusion of this paper indicates that “ShanghaiHong Kong Stock Connect Program” can serve as an effective external governance mechanism, promoting the regulation of corporate behavior and helping improve the efficiency of tax collection and management. This provides a theoretical basis for further deepening the opening up of the financial market.

Key words: “ShanghaiHong Kong Stock Connect Program”, corporate tax avoidance, corporate governance, information quality

摘要： 资本市场开放作为我国金融供给侧改革的重要内容，深刻改变了中国资本市场交易者结构特征，可能对上市公司的自利行为产生深远影响。本文基于沪港通这一准自然实验，研究发现资本市场开放能显著抑制企业的避税行为。影响机制检验表明，资本市场开放不仅有助于提高公司治理水平、抑制高管避税寻租动机，而且有助于改善公司信息质量、增加避税成本，从而降低企业避税水平。进一步研究还发现，这一影响对于税收征管强度较低地区的企业更显著。本文的研究结果表明，沪港通可以作为有效的外部治理机制，促进企业规范自身行为，提高税收征管效率。这为后续进一步深化金融领域开放提供了理论依据。

关键词: 沪港通, 企业避税, 公司治理, 信息质量 ,