生命周期、风险偏好和积累水平对DC型养老金资产配置策略的影响研究*

近年来,DC型养老金在我国得到了长足发展。DC型养老金的积累期长达数十年,如何通过有效的资产配置,实现参保人更高的养老效用是理论界和实务界都关注的问题。本文在默顿（Merton）连续时间最优投资-消费问题框架下,建立了DC型养老金最优资产配置问题的随机优化模型。以此为基础,本文研究了生命周期、风险偏好和积累水平对养老金积累期最优资产配置策略的影响。进而,通过Monte Carlo模拟,本文研究了最优资产配置策略与恒定资产配置比例策略下养老金积累效果的优劣。本文的结论证明,在放开DC型养老金投资限制的条件下,引入“生命周期基金”和“生命特征基金”,引导最优资产配置很有必要。     

基于随机利率和通货膨胀的缴费确定型养老金计划最优资产配置策略

在随机利率和通货膨胀的背景条件下,应用随机动态规划方法,提出一个连续时间数学模型来分析动态资产组合选择,主要研究缴费确定型养老金计划的最优资产配置策略,旨在使其最终实际财富的期望效用最大化.用Cox-Ingersoll-Ross(CIR)过程来模拟名义利率的动态变化,用通货膨胀指数化债券来有效的对冲通货膨胀风险.通过应用随机动态规划方法,得出在CRRA效用函数下的最优资产配置策略.最后通过数值分析并计算出解析解来说明动态投资策略,可以帮助缴费确定型养老金计划的参与者建立自己的养老基金投资组合,根据其风险厌恶程度从现有的个人养老金产品中进行选择,并提出基于养老金受益人生命周期及不同风险偏好的投资策略.     

中国养老保险新制度的经济学分析

文章用交叠世代模型考察中国2005年修订的部分积累制养老保险,分析个人缴费率、企业缴费率和人口增长率对资本劳动比、社会统筹养老金、个人账户本金、个人的消费和效用产生的影响。证明了提高个人缴费率会使个人账户本金增加,对资本劳动比、社会统筹养老金、个人的消费和效用都没有影响。提高企业缴费率会使资本劳动比和个人账户本金减少;在满足一定条件下才能使社会统筹养老金增加;在动态有效时会使工作期消费和效用下降。人口增长率下降会使资本劳动比和个人账户本金增加。因此,要增加个人账户本金,就应提高个人缴费率或降低企业缴费率或严格执行计划生育政策;值得注意的是提高企业缴费率不一定能增加社会统筹养老金。     

新农保补贴激励、政策认知与个人账户缴费档次选择--基于东北三省数据的有序Probit模型估计

根据新农保试点的跟踪调查结果,大多数参保农民都选择了最低的个人账户缴费档次。分析了个人账户财政补贴激励和政策认知程度对农民参保缴费档次选择的影响,利用有序Probit模型和东北地区调查样本数据对此问题进行了实证检验。在较高的政策认知条件下,"差别化"财政补贴方式比"一刀切"方式显著提高参保农民的缴费档次选择。其政策含义是在提高农民对新农保的政策认知程度基础上,依据个人账户的不同缴费档次建立多缴多补的"差别化"财政补贴激励机制,以引导农民自发选择较高缴费档次,从而提高新农保替代率水平。     

延迟退休年龄与养老保险收支余额:作用机制及政策效应

文章通过连续时间养老金收支模型分析认为延迟退休年龄对养老保险计划收支余额的影响来自四个方面的效应,即缴费年限效应、领取年限效应、替代率效应和差异效应。改革的最终效果是上述四种效应共同作用的结果。短期看,前两种效应占据主导;长期看,后两种效应也具有显著影响。延迟退休年龄的政策效果和工资增长率、养老金增长率、改革速度以及未来参保人口结构有关。理论分析和实证检验结果表明,无论从改革过程还是从对养老保险计划收支余额的影响看,延迟退休年龄都是一个复杂而渐进的过程,延迟退休年龄必将减轻政府在养老保险方面负担的传统说法并不全面。     

账户年金化与商业年金保险的发展

随着越来越多的养老金计划参保人进入退休阶段,账户积累基金在退休时如何给付值得重视,而对此问题目前国内的研究还不多。养老金账户余额是否采用年金保险形式发放关系到各种养老金计划的最终养老保险保障功能能否真正得以实现,而社会养老保险制度改革的一个重要目标就是帮助国民能有效地对抗老年风险。目前养老保险制度改革的一个趋势是基金积累制账户越来越普遍,这种账户主要解决的是基金如何积累的问题,而在给付阶段的老年风险问题则需要由年金保险这一保险机制来管理。如何加快发展商业年金保险市场,我们认为可以借鉴国际经验,从年金化政策上找到一些启示。     

风险投资中激励机制与代理成本分析

在风险投资机制中存在着双层委托代理关系,投资者设计激励制度时,必须将风险企业家的努力引入产出函数,建立相应的整合激励模型,分析影响风险投资家和风险企业家激励强度的若干因素,包括风险企业自身的股份份额、代理人的成本函数、外部不确定性和风险企业家的保留效用等,而为了使激励机制更有效,必须尽可能地减少机制运行的代理成本,影响该成本的因素主要包括风险投资家的利润分享份额,风险企业家的利润贡献率、风险态度等,从而根据这些影响因素,设计激励机制这一制度安排来保证两个委托人(投资者和风险投资家)的效用最大化.     

基于效用成本风险异质性的消费资本资产定价模型

资产定价既是现代金融的核心,也是许多困惑之所在,其中最著名的就是股权溢价之谜和无风险利率之谜。本文对消费资本资产定价模型中的效用成本做了重新思考,引入"效用成本风险异质性"的概念,并将效用成本区分为"消费效用成本"和"风险效用成本"。在此基础上,本文提出了消费资本资产定价模型的新形式,并对股权溢价之谜和无风险利率之谜进行解释。     

对离退休人员领取基本养老金资格认证刍议

冒领养老金是危害社会保险基金安全运行的首要问题。究其原因是发放形式的转变，企业监控力度的减弱，城市化建设使退休人员人户分离，异地居住现象的增多，现有发放手段、管理措施的滞后等等，这些因素的存在使得一些退休人员在利益的驱动下，主动或被动地弄虚作假，冒领养老金。为了社会保险事业的平稳发展，保证社会保险基金的安全，维护广大参保人依法享受社会保险的权利的利益，从根本上解决冒领养老金的问题已迫在眉睫。为了及时有效防止养老金冒领行为，笔者认为只要通过离退休人员领取基本养老金资格认证工作来掌握退休人员生存状况，来堵塞漏洞，确保基金安全。     

边际效用递减规律下的风险回避问题

人们为什么回避风险 ,其基本原理是什么 ,文章分析了边际效用递减条件下的效用。得出了在边际效用递减条件下 ,回避风险或承担风险有赖于人们的理性选择的结论。     

Public Pension Benefits Claiming Behaviour: new Evidence from the Japanese Study on Ageing and Retirement

The present study explores public pension claiming behaviour among the Japanese elderly. First, we perform financial simulations, estimate expected utility and depict the typical patterns of pension benefits over a lifecycle. We show that a beneficiary's optimal retirement age depends on that beneficiary's mortality risk, discount rate, initial wealth and risk attitude. Second, we use individual‐level data from the Japanese Study on Aging and Retirement (JSTAR) to empirically examine the determinants of claim timing. We find evidence that most of the factors examined in the simulation are, indeed, significantly associated with early claiming among wage earners of pension benefits.     

Occupation pension for public employees in the People's Republic of China: A new approach with defined benefit underpin pension plan

The State Council of the People's Republic of China announced a reformed pension plan for public employees with the occupation pension plan in January 2015, officially disclosing that the social pension systems for private and public employees will be unified. Our proposed occupation pension plan for public employees is one of the important components in transiting from a dual‐track pension system to a sustainable and unified system. We aim at providing a pension design, that is, the defined benefit (DB ) underpin pension with estimates of the costs and benefits. We have used a financial engineering approach to calculate the hedge contribution for a DB underpin hybrid pension plan benefit. We also treat pension benefit and salaries in aggregate. Therefore, we propose a stochastic and exogenous salary model. Employees’ total benefits can be determined by multiple factors, such as inflation, economic environment, and employer's preference. However, the expectation of employees’ total benefits should not be affected by the change of salary and pension benefits. Our results could facilitate the ongoing pension reform in the People's Republic of China, providing a rigorous benchmark with public policy implications as to plan design, cost estimation, as well as risk management approach.     

Intergenerational Risk Sharing,Pensions, and Endogenous Labour Supply in General Equilibrium*

We show that a two‐tier pension system, with a pay‐as‐you‐go first tier and a fully funded, defined wage‐indexed second tier, can provide for optimal intergenerational risk‐sharing without distorting the labour supply, thereby achieving the first best. Other arrangements with a fully‐funded second tier fail to achieve the first best.     

Voluntary participation and intergenerational risk sharing in a funded pension system

We explore the feasibility of a funded pension system with intergenerational risk sharing when participation in the system is voluntary. Typically, the willingness of the young to participate depends on their belief about the future young's willingness to do so. We characterise equilibria with voluntary participation and show that the likelihood of their existence increases with risk aversion and financial market uncertainty. We find that mandatory participation is often necessary to sustain a funded pension pillar and to let participants benefit from intergenerational risk sharing.     

Social Security Systems,Human Capital,and Growth in a Small Open Economy

We consider a small open economy in which the level of public education funding is determined by popular vote. We show that growth can be enhanced by the introduction of pay‐as‐you‐go pensions even if the growth rate of aggregate wages falls short of the interest rate. The reason is that the pay‐as‐you‐go (PAYG) system allows future retirees to partially internalize positive externalities of public education due to the positive effect of higher future labor productivity on their pension benefits. The majority support for education funding will be especially strong when the PAYG benefit formula is flat, i.e., progressively redistributive. If a flat benefit PAYG pension system is in place then the economy will achieve the highest growth rate relative to the alternative pension system designs. While such PAYG pension system may be opposed by the majority of working individuals due to inferior returns to their pension contributions relative to a funded scheme, it is likely to be politically sustained by a coalition of older individuals and lower income workers.     

Overview of the Portuguese Three Pillar Pension System

In order to cope with alleged future financial problems, several changes were made to the design of the Portuguese pension system since 2000. The aim was to achieve the diversification of retirement income sources across providers, both public and private, across the three pillars: public, industry-wide, and personal, and also across the financing forms of pay-as-you-go and funded. This paper describes these changes and analyses the results regarding, principally, the weight of each pillar and the investment performance of both public pension reserves and private pension funds. The main finding is that, in effect, there is one substantial longstanding pillar, and that is the public system.     

Pension Reform and Economic Performance Under Imperfect Capital Markets

We consider an overlapping generations model where heterogeneous agents take decisions on consumption and investment in education under the assumption of imperfect capital markets. We study how the introduction of a pay-as-you-go and of a fully funded pension scheme affects output and lifetime opportunities, and then analyse the impact of a pension reform. The standard neutrality result for fully funded pension schemes does not hold in this framework. We establish the conditions under which a fully funded scheme is associated with a higher investment in human capital. We show that the transition path may involve poverty traps     

社会养老金金融功能的制度安排研究

社会养老金制度设立方式直接关系到一国经济体系的健康运行和发展.从社会养老金制度的产生和相当长的发展过程中,大多数国家大体上都是采用的随收随支的制度.这种制度一般只从政治、社会的安定等原因而设立的,没有考虑社会养老金制度对国民经济发展的直接作用,社会养老金制度只有社会保障功能.社会养老金制度合理安排金融功能,能够使社会养老金积累规模巨大的长期储蓄资金,促进资本市场的成熟发展,对经济发展产生巨大的推动作用,社会保障功能也得到加强.     

不同生育率情形下养老保险筹资模式比较研究*

理论研究普遍认为,基金制养老保险筹资模式优于现收现付制,但这几乎都是基于人均资本视角的判断。本文在外生和内生生育率两种情形下,从福利经济学视角分析基金制是否完全优于现收现付制。理论模型表明,在一定参数组合下,无论外生生育率还是内生生育率,都存在使现收现付制下社会福利高于基金制下社会福利的养老保险缴费率。模型的数值模拟显示,存在使现收现付制下社会福利更高的养老保险缴费率,且在外生生育率下（符合我国生育政策）现收现付制缴费率在12%左右社会福利最高,内生生育率下（符合发达国家生育政策）现收现付制缴费率在6%左右社会福利最高。前一数值与已有研究成果观点相近(我国社会统筹部分缴费率应下降到15%左右),后一数值与美国（62%）、日本（77%）等发达国家现收现付制养老保险缴费率相近。稳健性检验显示,只要参数赋值在合理范围内,数值模拟主要结论不变。本文为降低现行我国社会统筹部分养老保险缴费率提供了理论借鉴。