Abstract: The reduction of the pension insurance contribution rate reduces the burden of enterprises and is conducive to the realization of a virtuous circle between the development of enterprises and the development of the pension insurance system. Existing studies mostly focus on the impact of reducing the pension insurance contribution rate on employees' income and employment, and there is little literature on the impact of reducing the pension insurance contribution rate on the internal income gap of enterprises. Based on the data of A-share listed companies from 2012 to 2022, the article uses the double-difference method to examine the impact of the 2019 pension insurance contribution rate reduction policy on the intra-enterprise income gap. It is found that reducing the pension insurance contribution rate significantly reduces the intra-enterprise income gap. The mechanism test shows that reducing the pension insurance contribution rate can reduce the intra-enterprise income gap by promoting enterprise innovation and alleviating enterprise financing constraints. Heterogeneity analysis shows that for small-scale enterprises, capital and technology-intensive enterprises, enterprises in eastern cities and enterprises in central cities, the inhibiting effect of reducing the pension insurance contribution rate on the intra-enterprise income gap is more significant. Further analysis shows that the impact of the pension insurance contribution rate reduction policy on the intra-enterprise income gap is more pronounced when the pension insurance contribution rate reduction is relatively large. The findings of the study provide empirical evidence and decision-making references for promoting the reform of the pension insurance contribution system, further improving the redistribution adjustment mechanism, and thus promoting the fairness of income distribution.

Key words: reform of the pension insurance contribution system, pension insurance contribution rates, intra-enterprise income gap