高新技术企业所得税优惠多多益善吗?——基于CGE模型的分析

The More the Preferential Income Tax, The Better for High-tech Enterprises?—— An Analysis Based on Computable General Equilibrium(CGE) Approach

对于我国各地竞相降低所得税负以吸引高新技术企业的做法,现有研究未能基于一般均衡角度分析其不利影响。文章通过在可计算一般均衡模型中引入以往研究所忽视的高新技术企业所得税率和风险报酬系数变量,利用"两税合并"前后的实际经济运行数据,分析了最优所得税率及其变化与一般均衡影响。研究发现,基于社会福利最大化角度,高新技术企业最优所得税率分别为18.24%和17.93%,且随着其风险报酬系数的增加而下降,并与CES生产函数的要素替代弹性分别呈正相关和倒U型关系。进一步对比不同均衡发现,过多的所得税优惠所带来的投资增长,是以社会整体福利和高新技术企业就业、产出及效率的下降为代价,且这种代价在非高新企业统一税率情形更为显著。因此,规范各地高新技术企业所得税优惠政策,在当前我国经济瓶颈已从投资约束转向效率约束的背景下,尤显必要。

The existing research has not been able to analyze, from the perspective of general equilibrium, the adverse effects of the practice of reducing corporate income tax burden to attract high-tech enterprises by Chinese local governments. The paper, by introducing income tax rate variable and risk compensation coefficient variable of high-tech enterprises to a computable general equilibrium model, which are ignored by the previous research, and using the actual economic data before and after ＂the combination of the two taxes＂, analyzes the influence of the optimal income tax rate and its change on the general equilibrium. The study shows that the optimal income tax rates of high-tech enterprises, based on the maximization of social welfare, are 18.24% and 17.93% respectively, decrease with the increase of risk compensation coefficient, and the relationship with the factor substitution elasticity of CES production function presents a positive correlation and an inverted U relation respectively. The further contrast between different equilibrium finds that the growth of investment caused by excessive preferential income tax is at the expense of the decline in the overall welfare of society and the employment, output and efficiency of high-tech enterprises, and the price is more significant in an unified tax rate for non high-tech enterprises. Therefore, Chinese local governments should modify their preferential tax policies for high-tech enterprises, especially in the context of economic development＇ s constraint having shifted from investment to efficiency.