资本市场开放与民营企业融资约束——基于深港通的实证研究
Capital Market Opening and Private Enterprise Financing Constraints—An Emrirical Study Based on “Shenzhen-Hong Kong Stock Connet”

2016年12月5日，“深港通”的启动建立了深圳与香港两市间资本的联通机制。相较于国有企业，我国民营企业由于其自身特征往往外部融资渠道有限，企业与外部信息不对称程度较高、委托代理成本较高，所面临的融资约束困境较为严峻。现有大量文献已经证明资本市场开放能够通过增加市场资金供给、加强公司治理的外部监督、改善信息环境、促进金融市场发展等路径缓解企业面临的外部融资约束问题。但实际上，从“深港通”实施至今，仍处于初期运行阶段，数据新颖，资料相对匮乏。基于上述背景，本文以“深港通”启动作为资本市场开放的代理变量，选取我国深圳证券交易所2015~2018年间民营上市公司数据，通过刻画KZ指数来衡量民营企业外部融资约束程度，运用经典双重差分模型，实证检验深港通机制对我国民营企业融资约束的影响；并进一步考察在不同公司规模、不同审计质量条件下，民营企业间融资约束缓解程度是否存在显著差异。最后本文进行了稳健性检验，从PSM匹配对照组样本、变换模型、以SA指数度量企业融资约束三个角度验证结论的可靠性。
On December 5, 2016, the launch of the “Shenzhen-Hong Kong Stock Connect” established the capital connection mechanism between Shenzhen and Hong Kong. Compared with state-owned enterprises, Chinese private enterprises, due to their own characteristics, often have limited external financing channels, enterprises and external information asymmetry is higher, the principal-agent cost is higher, the financing constraints of the dilemma is more severe. A large number of existing literatures have proved that the opening of the capital market can alleviate the external financing constraints faced by enterprises through increasing the supply of market funds, strengthening the external supervision of corporate governance, improving the information environment and promoting the development of financial markets. But in fact, since the implementation of Shenzhen-Hong Kong Stock Connect, it is still in the initial stage of operation, with novel data and relatively scarce data. Based on the above background, this paper takes the launch of “Shenzhen-Hong Kong Stock Connect” as the proxy variable of the opening of the capital market, selects the data of private listed companies in Shenzhen Stock Exchange from 2015 to 2018, and measures the degree of external financing constraints of private enterprises by describing the KZ index. To empirically examine the influence of Shenzhen-Hong Kong Stock Connect mechanism on financing constraints of Chinese private enterprises; and further investigate whether there are significant differences in the degree of financing constraint alleviation among private enterprises under different company sizes and audit quality conditions. Finally, the robustness test was carried out to verify the reliability of the conclusions from three perspectives: PSM matching control sample, transformation model, and SA index measuring corporate financing constraints.