资本市场开放对企业内部薪酬差距的影响——基于“沪港通”的准自然实验

本文利用沪港通开通这一“准自然实验”构造双重差分模型,实证检验了资本市场开放对企业内部薪酬差距的影响。研究发现:(1)沪港通的开通显著缩小了企业内部薪酬差距,并且在剔除“限薪令”、股权激励、最低工资制度等因素的干扰之后,这一效应依然显著,其他稳健性检验方法也证实了这一结论的可靠性,因此沪港通开通并非是近几年来中国企业内部薪酬差距乃至总体收入差距扩大的原因;(2)资本市场开放显著地提升了上市公司监事会持股比例,但降低了董事会持股比例,从而通过强化监事会的监督力度来缩小企业内部薪酬差距,当然内部监督的中介效应仅存在于A股企业中,因为非A股(B股、AH股、AB股)企业开放程度已经较高,受沪港通的冲击较小;(3)企业所处外部法律环境对资本市场开放影响企业内部薪酬差距产生了调节作用,A股企业相比非A股企业外部法律环境更为单一,资本市场开放使得入选沪港通标的范围的A股企业面临的外部法律环境约束增强,因而缩小企业内部薪酬差距的程度也更为显著。本文的研究有助于厘清资本市场开放的收入分配效应,可以为党的十九大报告所提出的“深化资本市场对外开放”和“促进收入分配更合理更有序”提供理论和经验证据支持。

Effect of Stock Market Liberalization on Internal Pay Gap in Enterprises:Evidence from Shanghai-Hong Kong Stock Connection

China has steadily promoted the liberalization of the stock market in recent years,which has profoundly affected the development of China's capital market.On the one hand,the involvements of capital and foreign institutional investors have affected the internal supervision mechanism of enterprises;On the other hand,the external legal environment around enterprises has also changed after the stock market liberalization.However,it should be noticed that Chinese income inequality has expanded after the reform and opening up since 1980s.In particular,the income Gini coefficients from 2015 to 2018,according to the National Bureau of Statistics,have increased from 0.462 to 0.474,which was just after the Shanghai-Hong Kong Stock Connection in 2014 launched by Chinese government.Thus,is there some connection between capital market liberalization and income inequality?As Shanghai-Hong Kong Stock Connection in 2014 is a perfect“quasi-natural experiment”,this paper empirically test the impact of this policy shock on the internal compensation gap using data from Chinese listed companies,based on Difference in Difference(DID)model.The results show that the Shanghai-Hong Kong Stock Connection has narrowed the internal compensation gap of enterprises,and this narrowing effect is continuously significant in the following years.Moreover,the narrowing effect of Shanghai-Hong Kong Stock Connection on internal compensation gap of enterprises is still significant after eliminating the interference factors such as the central government-oriented enterprises'“limit pay order”,equity incentive and minimum wage system;and other methods of robustness test have also confirmed the reliability of this conclusion.Therefore,Shanghai-Hong Kong Stock Connection is not one of the reasons for the widening of the internal pay gap and even the overall income gap in China in recent years,although both of which have expanded since 2015.The empirical evidence supports the opinion that the internal supervision structure of enterprises has changed after Shanghai-Hong Kong Stock Connection.The opening of the stock market has significantly increased the shareholding of the board of supervisors in the enterprise.However,the shareholding of the board of directors is decreased after the stock market liberalization.Therefore,the internal salary gap is reduced by strengthening the supervision of the board of supervisors,for who represents the interests of ordinary employees.It should be noted that the intermediary effect of internal supervision only exists in A-share companies,because non-A-share(B-share,AH-share,AB-share)companies are more opening and less affected by Shanghai-Hong Kong Stock Connection.Additionally,the results of mechanism test also indicate that external legal environment around the enterprises has moderated the influence of Shanghai-Hong Kong Stock Connection on the internal pay gap.Specifically,as the external legal environment of A-share companies is weaker than that of non-A-share companies,it has been strengthened after the opening of the capital market,which makes the reduction of internal pay gap much more significant.As the external legal environment of non-A-share companies is more diversity,resulting in stronger external oversight.Therefore,compared with A-share companies,these companies are less affected by the impact of Shanghai-Hong Kong Stock Connection.The contributions in our study are as follows.Firstly,the research in this paper reveals the narrowing effect form Shanghai-Hong Kong Stock Connection on the internal compensation gap of enterprises,which is conductive to the clarification of the income distribution effect caused by stock market liberalization.Secondly,the mechanism tests also indicate that internal supervision structure and external legal environment of the enterprises are two important factors which play roles in the narrowing effect.At last,our study can provide theoretical and empirical support for the“deepening capital market liberalization to the outside world”and“promoting income distribution more rational and orderly”proposed by the party's 19th National Congress report.