资本市场开放影响企业多元化经营吗？—— 基于 “陆港通” 机制的准自然实验

Diversification is both an important strategic choice and an investment decision for enterprises. Based on A-share non-financial listed firms from 2007 to 2019, this paper uses the quasi-natural experiment opened by the “Mainland-Hong Kong Stock Connect” to empirically test the impact of capital market openness on corporate diversification. The study finds that the openness of the capital market reduces the degree of corporate diversification, especially non-related diversification, by easing enterprises’ agency costs and financing constraints. The heterogeneity analysis shows that a more competitive market environment, fewer in-house resources, and a higher level of executive overconfidence strengthen the dampening effect of capital market openness on corporate diversification. The analysis of economic consequences shows that capital market openness positively regulates the relationship between corporate diversification and corporate value. This paper shows that capital market openness represented by the “Mainland-Hong Kong Stock Connect” can optimize the decision-making of diversified operations, which provides a reference value for further improving the level of capital market openness and building a capital market system that supports the high-quality development of firms.