社会保障基金最优持股比例研究

The Optimal Transfer Shares of State-owned Firms to Social Security Fund

在不考虑信息不对称和外部性的条件下,在无穷期生命期限模型中,中央计划经济和竞争性均衡经济的结果是完全等价的;但是在有限生命期限模型中(如代际交叠模型等),中央计划经济和竞争性均衡经济的等价关系就不一定成立,而且在"动态无效率"的情况下,竞争性均衡是帕累托无效的,这时就有必要引入政府来调节经济效率。本文在代际交叠模型中引入国有股形式的社会保障来研究最优社会保障基金持有国有股的比例。研究发现:通过调节社会保障基金的持股比例可以实现中央计划经济和竞争性均衡经济的等价,实现最大的社会福利,从这个角度出发就可以确定最优的社会保障基金的持股比例。本文的结论对全国社会保障基金在未来的实际运作有指导意义。

Without asymmetric information or externality, the social planned equilibrium is equivalent to the competitive equilibrium in an infinite horizon framework; however, in a finite horizon model, it can be proved that this equivalence will not held yet. Because of the possibility of dynamic inefficiency, the competitive equilibrium is not Pareto-optimal. This paper introduces the transfer of state-owned shares to social security fund in an overlapping generation model to study the optimal transfer of shares. The optimal transfer share of state-owned firms to social security fund can be determined by the replication of the social planned equilibrium with the competition equilibrium. The conclusion is greatly helpful for the operation of China＇s NSSF（ National Social Security Fund）in the future.