资产价格、资本流动与人口结构

【作者】 邹达川；

【导师】 尹翔硕；

【作者基本信息】 复旦大学 ， 世界经济， 2008， 博士

【摘要】 在人类历史上,人们从来没有像今天这样活得更长寿,但同时,老年人比例的增加也给经济、社会带来了巨大的影响。平均寿命延长伴随出生率的降低,这两者导致了老龄化社会的到来。从宏观经济层面看,老龄化增加了整个国家的养老负担和健康支出,老龄化尤其严重的地方,更会带来财政危机。虽然是世界性的挑战,但还没有一个超国家的组织可以解决老龄化问题。人口结构变化会引起实质经济与金融市场的相关反应,人们开始对养老金制度进行不同程度的改革,经济理论文献对此进行了大量探讨。人口结构变化是一个长期的经济现象,其如何影响经济增长有其内在的传导机制。比如说,老龄化社会到来的某一阶段,资产价格或资本回报会有所下降;国际资本流动的长期因素中,部分由于人口结构变化的不同步引起;老龄化带来的风险可以在世界范围内进行一定程度的分散或者说分担;养老金投资的战略方向也会发生相应的变化;上述未来可能发生的情景构成本文研究的基本逻辑。我们的着眼点落在人口老龄化趋势的地区差异上,主要表现为不同地区老龄化速度和时间上的差异。在金融全球化的今天,资本流动自由度大大增加,在资本市场高度一体化的背景下,老龄化和养老金制度的变革通过要素的国际流动对各国经济带来长期性和根本性的影响,也为老龄化问题的解决提供了新的思路。本文将在开放经济条件下对人口结构与资产价格及资本流动的关系进行分析,并对养老金的全球化投资进行探讨。考虑到世界人口结构的地区差异和老龄化的速度并不一样,如果我们把分析对象放到一个开放经济的条件下进行分析,如允许资本流动和移民的情况下,一个国家或者地区的人口结构及老龄化的速率通过要素的流动成为“可控量”,在一定程度实现人口结构的“年轻化”并降低老龄化的速度,从而为解决人口老龄化问题提供了一种在理论和实践上都可行的解决思路。本文仅考虑资本这一要素的流动,遵循这一思路,本文作了以下三个层次的分析:第一层次,主要分析了封闭经济条件下人口结构与资产价格的关系。由于资产价格长期决定于资本的真实回报率,短期则取决于供求关系,所以从两个角度分析了人口结构对资产价格的影响。首先采用迭代模型分析与人口结构相关的储蓄、投资和消费行为,通过这些因素对经济增长的影响以及对资本和人口这两种要素的分配效应,得出人口结构会影响资产价格变动的结论;另一方面在金融市场上,从生命周期假说出发,不同年龄的投资者对风险及投资收益有不同的偏好,未来某一时段老龄化会导致资产供给大于需求,推动资产价格下降。这一结论对养老金体制改革有着很强的政策意义:源于人口结构的金融市场风险将成为各国政府考虑的重要问题。这一层次主要论证了封闭经济下老龄化会带来资产价格变动这一命题。第二层次是扩展到开放经济的分析,老龄化是世界趋势,但各个国家老龄化的速度和时机并不同,所以其长期资本回报也是不同的。在资本完全自由流动的假设前提下,通过快速老龄化地区向慢速老龄化地区的资本流动,资本回报可以更缓慢的下降。另一方面,由于人口结构诱发的金融市场风险在资本流动高度一体化背景下可以快速蔓延,有可能产生得到更坏的结果,所以人口结构与风险分担之间关系的剖析成为与现实最为接近的考虑。由于现实中现收现付制仍是养老体制的主要模式,在开放经济条件下,风险可以在国际范围内分担,与现收现付制相结合的国际风险分担机制的构建,成为近期应对老龄化问题的主要解决办法。第三层次的分析集中于基于投资学的实务考察。在前面实质经济分析的基础上,结合有关文献对养老金全球化投资的现实情况进行剖析,讨论了养老金全球化投资现实管制与潜在收益,表明实际的国外投资收益低于理想水平是因为不同国家对全球化投资进行限制的结果,放开国外投资限制能提高养老金的收益水平或有效分散风险,因此通过适当的政策创新和制度创新,在合理的全球化分散投资策略下,能够实现养老金投资的更高收益。最后,针对目前养老金全球化投资的主要载体——主权养老基金与主权财富基金进行了较为全面的分析,并提出了我们的政策建议。总之,从世界范围内,面对各国人口结构的老龄化趋势和养老制度改革带来的问题,养老金的全球化投资有利于解决一国面临的老龄化问题。人口与实质经济的关系表明全球化投资的合理性与必要性,而日益全球化的金融市场则为其提供了现实可行性,主权养老金集中体现了这一趋势,也是全球化投资重要的载体和实践方式。虽然目前各国还存在各种对外投资的障碍,但通过适当的政策创新和制度创新仍然可以有效改善这一状况,通过养老金的全球化投资来促进世界经济的增长和平衡,并最终为世界的老龄化人群提供更多可分配的物品和劳务。通过把视野从一个国家扩展到世界范围内,实际上为解决各国面临的老龄化问题提供了一种新的思路,这也是本文研究的现实意义所在。同时,本文最后提出了进一步的研究方向。更多还原

【Abstract】 In human history, never can people live so longer like today. Meanwhile, Increasing in proportion of the old-age population and the degree of the population ageing process also produce intermediate ageing effects on both the economy and the society. While increasing longevity and lower fertility also lead to the coming of ageing society.From the viewpoint of macroeconomic levels, this development lays burden on the government in the form of pension funds and expenditures on medical care. Worsening of the ageing problem may cause fiscal crisis.Owing to ageing problem now become an international challenge thing, there is still no a supernational organization that can find a solution to handle it.Changes in demographic structure directly give rise to reactions between the entity economy and the financial markets. This aspect of changes and levels already catches people’s eyes on the reform pension system, many economic theroritical literatures have done much research regarding to this problem. Changes in demographic structure as a long-run economic phenomen,how it affects economic growth can be starting from economic phenomen.For example,when the society stays a certain stage of the ageing sociey,asset price and capital return may decline in a certain degree;Among those long term factors of international capital mobility,partly due to unharmonious changes in demographic structure; Dangers arising from ageing problem,to what exten,can be diversified and shared around the world; What we have mentioned above is the basic logic of our research.What we research mainly focus on .regional difference of ageing population trends, There are, however, important differences in the pace and degree of ageing. Under the situations of financial globalization, capital mobility increases greatly, investment and capital market becomes more integrated,ageing and reform of pension system can bring national economis long run and fundmental influences through factor flows across national bordrers,and this provides a new idea to find a solution for ageing problem. Under assumption of open economy model, this paper maily discuss relationships between demographic structure,asset price and capital flows, meanwhile, probe into global investment of pension funds.Considering regional difference of world-wide demographic structure and ageing pace in differnent regions, we continue our studies under conditions of open economy model, assume capital flows and migrations permitted, demographic structure (a nation,or a region) and ageing ratio as a variable through factor mobility,to a certain degree, can realize "younger"demographic structure and mitigate ageing pace, and it, in theory and practice, provides a feasible solution for ageing problem. Our paper considers capital flows only, and on the basis of this, the paper further our studies in three levels as follws:First level mainly discusses relations between demographic structure and asset price in a closed economy. Owing to asset price depends on capital’s real return rate in long time, and relationship between demand and supply in short time. Therefore, the paper analyzes how demographic structure affects asset price in two aspects. By using over-lapping model, we first analyze savings, investment and consumptiong behaviors which are relating to demographic structure. Based on these factors’ effects on economic growth and its "allocation effects" on capital and population, we draw a conclusion that demographic structure can cause changes in asset price ; on the hand, according to life-cucle hypothese,investor at different age stage has different preference towards different risks and returns in financial markets. Ageing can cause asset supply over demand at some future day, and also can drive asse prcie down. This section mainly gives proofs how ageing brings asset price change in a closed economy.LevelⅡbeing extended into an open economy model, ageing as a world wide trend, however, the pace and degree of ageing at different countries (or regions) are different, long term returns on pension funds also is different. Under assumptions of perfect capital mobility, capital flows from those fast ageing areas to those slow ageing areas, capital returns declines more slow. On the hand, in reality, pay-in and pay-out system still is the main model of pension system, under conditions of open economy, risks can be shared across world, so constructing a worl-wide risk-sharing mechanism in line with pay-in and pay-out system may be a solution to ageing problem.LevelⅢanalyze mainly from economics of investment. Based on above-discussions about entity economy, in line with related literatures, we further study real situations of global investment of pension funds. The paper also studies the global investmen benefits and consraints of pension funds, we find that real investment level below expected level lies in restrictions on investment of pension funds across different countries. Increasing investment in foreign countries can increase pension fund returns or effectively diversify its risks. This section finally gives the major global investment vehicle of pension funds -sovereignty pension fund and sovereignty wealth fund-a comprehensive and comparative study, we put forward some policy suggestions.In summary,To study relations between demographic structure and capital,in attempating to gaining theoretical support of economics for global investment of pension funds,theories ang analysis tool used in the paper mainly including neo-classical economic growth theory, related theoretical model in international economics, and tools such as dynamic simulations and equilibrium analysis and the like,as to study approaches, I mainly use a OLG (overlapping generation) model so that the paper can study how the changes in population structure affects asst price in financial markets,capital flows and risk-sharing mechanism, of course, under different background and different assumptions, OLG model being extended.These approaches are mainly normative ways, without question, we also use emprical metods to probe into those activities in the real world.Finally, the further research trends have been pointed out in the last chapter of thedissertation.更多还原