Reforming social security: assessing the effects of alternative funding strategies

Population ageing implies that the large pay-as-you-go social security programmes implemented in many OECD economies will run into severe financial problems. By means of a numerical overlapping generations model, this paper investigates the intergenerational welfare effects of a transition to funded security programmes. Such programmes imply permanent increases in the welfare of the young and unborn generations. It is demonstrated that the size of the welfare gains varies significantly between alternative funding strategies. A nonindividualized funding strategy characterized by increased government asset accumulation triggers considerable welfare gains through increased asset returns in the future. Even larger welfare gains may be realized by an individual funding strategy characterized by increased asset accumulation accompanied by an adoption of actuarial supplementary pensions (i.e. actuarial supplementary pensions combined with a fixed minimum pension) which reduces future tax distortions drastically.     

Intergenerational transfers and the social discount rate

This paper investigates the relationship between intergenerational asset transfers and the choice of the discount rate for use in cost-benefit analysis in a model of a competitive overlapping generations economy constrained by a socially managed exhaustible resource. Provided that there are no distortions in capital markets and that all agents hold perfect foresight, cost-benefit techniques will result in a Pareto efficient resource allocation if the discount rate is set equal to the market rate of interest. But since the path of the interest rate depends on the level of intergenerational transfers, cost-benefit techniques do not ensure a socially desirable distribution of welfare between generations; a social optimum will result only if intergenerational transfers are properly chosen and enforced. Decentralized private altruism may result in intergenerational transfers that both present and future individuals would agree are too small if members of the present generation attach positive weight to the general welfare of future generations, not simply their personal descendants. In a world where intergenerational transfers are non-optimal, second-best policy-making may imply a constrained optimum that is inefficient. Together, these findings suggest that cost-benefit analysis is at best a partial criterion to policy formulation that should be used only in conjunction with ethical principles that define the proper distribution of welfare between present and future generations.     

Asset bubbles in an overlapping generations model with endogenous labor supply

This paper examines the effects of asset bubbles in an overlapping generations model with endogenous labor supply. We show analytically that asset bubbles can lead to an expansion in steady-state capital, investment, employment and output under certain conditions.     

PRODUCE OR SPECULATE? ASSET BUBBLES,OCCUPATIONAL CHOICE,AND EFFICIENCY*

We study the effects of rational asset bubbles in an overlapping‐generations economy where asset trading requires specialized intermediaries and agents freely choose between working in the production or the financial sector. Frictions in the market for deposits create rents in the financial sector that affect agents’ occupational choices. When rents are large, the private gains associated with trading bubbles lead too many agents to become speculators, causing bubbles to lose their efficiency properties. Moreover, if speculation can be carried out by skilled labor only, then bubbles displace skilled workers away from the productive sector and raise income inequalities.     

Asset bubbles,labour market frictions and R&D‐based growth

Employing an overlapping generations model of R&D‐based growth with labour market frictions, this paper examines how employment changes induced by labour market frictions influence asset bubbles and long‐run economic growth. Asset bubbles can (cannot) exist when the employment rate is high (low), which leads to higher (lower) economic growth through labour market efficiency. We also explore the steady state and transitional dynamics of bubbles, economic growth and employment. Furthermore, we show that policy or parameter changes with a negative influence on the labour market can lead to a bubble burst.     

GROWTH AND BUBBLES WITH CONSUMPTION EXTERNALITIES*

This paper explores the role of consumption externalities in an overlapping generations economy with capital accumulation. If consumers in each generation are concerned with other agents’ consumption behaviours, there exist intergenerational as well as intragenerational consumption externalities. It is the presence of intergenreational consumption externalities that may produce fundamental effects both on equilibrium dynamics and on steady‐state characterization of the economy. This paper demonstrates this fact in the context of a simple model of endogenously growing, overlapping‐generations economy with or without asset bubbles.     

Fiscal rules and the intergenerational welfare effects of public investment

A common argument against balanced-budget fiscal rules has it that the costs of durable public capital fall entirely on current generations while its benefits also accrue to future generations. This paper proposes an additional argument whereby balanced-budget rules imply uneven welfare effects of public investment across generations. Using an overlapping generations model of a small open economy, I show that, when subject to a balanced-budget constraint, public investment causes a negative financial wealth effect on current generations. Numerical simulations of the model show that, in terms of welfare, this negative financial wealth effect more than offsets the productivity gains of higher public investment spending, leaving current generations worse-off. A golden rule exempting net public investment from the balanced-budget requirement overturns this effect and allows for welfare gains to both current and future generations. Allowing for debt-financing may thus be necessary to ensure public support for efficient increases in public investment spending.     

Double Bubbles in Assets Markets With Multiple Generations

We construct an asset market in a finite horizon overlapping-generations environment. Subjects are tested for comprehension of their fundamental value exchange environment and then reminded during each of 25 periods of the environment's declining new value. We observe price bubbles forming when new generations enter the market with additional liquidity and bursting as old generations exit the market and withdrawing cash. The entry and exit of traders in the market creates an M shaped double bubble price path over the life of the traded asset. This finding is significant in documenting that bubbles can reoccur within one extended trading horizon and, consistent with previous cross-subject comparisons, shows how fluctuations in market liquidity influence price paths. We also find that trading experience leads to price expectations that incorporate fundamental value.     

Temporary bubbles

This article studies the dynamics of an overlapping generations model with capital, money and cash-in-advance constraints. The economy can exhibit two different regimes. In the first one, the cash-in-advance constraint is binding and money is a dominated asset. In the second one, the constraint is strictly satisfied and money has the same return as capital. When the second regime holds on a finite number of periods, we say that the economy experiences a temporary bubble. We prove that temporary bubbles can exist in an economy, which would experience under-accumulation without money. We also show that cyclical bubbles may occur.     

Environmental Abatement and Intergenerational Distribution

This paper employs an overlapping-generations model to explore the impactof public abatement on private investment and the intergenerationaldistribution of welfare. Whereas public abatement benefits the oldestgenerations in terms of non-environmental welfare, future generations gainmost in terms of environment welfare. The overall benefits tend to besmallest for generations born at the time of the unanticipated policy shock.Public debt policy, however, can be employed to ensure that welfare gainsare distributed more equally across the various generations. Such a policyimplies that natural capital crowds-out man-made capital.     

TESTING FOR SPECULATIVE BUBBLES USING SPOT AND FORWARD PRICES

The probabilistic structure of periodically collapsing bubbles creates a gap between future spot and forward (futures) asset prices in small samples. By exploiting this fact, we use a recently developed recursive unit root test and rolling Fama regressions for detecting bubbles. Both methods do not rely on a particular model of asset price determination, are robust to explosive fundamentals, and allow date stamping. An application to U.S. dollar exchange rates provides evidence of bubbles during the interwar German hyperinflation, but not during the recent floating‐rate period. A further application to S&P 500 supports the existence of bubbles in the U.S. equity market.     

Does Money Always Make People Happy?

This paper presents an overlapping generations model with private information, in which the use of fiat money and the rampant moral hazard incentives sustain each other. It is shown that there is a monetary equilibrium, despite the fact that the rate of return on the nonmonetary asset is significantly higher than the rate of economic growth in the nonmonetary case; the valuation of money is not necessarily Pareto-improving, but rather can be harmful to almost all generations; an inflationary policy can improve the welfare of all generations except the initial one. Journal of Economic Literature Classification Number: E41.     

Welfare Analysis of a Fiscal Reconstruction Policy in an Overlapping Generations Economy with Public Investment

Constructing an endogenously growing overlapping generations model with public investment, we examine the welfare effects of a fiscal reconstruction policy. In this paper we define a fiscal reconstruction policy as a policy where the government reduces its spending level without changing the tax revenue and allocates the surplus of the revenue to redeem public debt. We show that if government spending is not productive it is possible that a fiscal reconstruction policy improves the utilities of both the current and future generations, while if government spending is productive it can harm the utilities of both generations. Received February 26, 2002; revised version received July 8, 2002 Published online: February 17, 2003     

Intergenerational Redistribution with Short-lived Governments

We study the politics of intergenerational redistribution in an overlapping generations model with short-lived governments. The successive governments—who care about the welfare of the currently living generations and possibly about campaign contributions—are unable to pre-commit the future course of redistributive taxation. In a stationary politico-economic equilibrium, the intergenerational transfer in each period depends on the current value of the state variable and all expectations about future political outcomes are fulfilled. We find that there exist multiple stationary equilibria in many political settings. Steady-state welfare is often lower than it would be in the absence of redistributive politics.     

资产价格泡沫与货币政策应对——事先行动还是事后反应

资产价格泡沫的产生原因是多方面的,早期的研究更多地认为资产泡沫来自于投资者的非理性因素,但是随着金融自由化进程的推进,与经济金融发展水平不相适应的金融自由化也成为资产泡沫产生的一个重要原因。而对于资产价格泡沫的货币政策应对一直存在争议,一些学者主张货币政策应该忽略资产价格,而另一些学者则主张货币政策应该对资产价格作出反应。本文基于后一种观点,来探讨当预期资产价格将出现泡沫时,货币政策是该事先行动还是事后反应,为此,本文引入产出跨期配置的理论,来阐述货币政策应对资产价格泡沫的决策模型。     

CLIMATE CHANGE AND OVERLAPPING GENERATIONS

This paper examines the interplay between discounting and the distribution of welfare between generations in formulating climate change response strategies. The analysis shows that one can understand Nordhaus's (1994) standard representative agent model for climate policy analysis as a reduced form of an overlapping generations model that embodies more realistic demographic assumptions. In this setting, alternative Pareto efficient allocations may be supported as competitive equilibria given appropriate sets of income transfers between generations. Numerical simulations establish that increased intergenerational transfers entail reduced monetary discount rates and increased rates of greenhouse gas emissions abatement. Short-run policy choices are highly sensitive to normative judgments concerning the relative weight attached to the welfare of future generations.     

Bubbles in Stochastic Economies: Can They Cure Overaccumulation of Capital?

It is well known that bubbles possess the potential to increase economic welfare due to a reduction of capital accumulation in deterministic overlapping generations economies that are in a dynamically inefficient state. However, actual economies are stochastic, where the concept of dynamic efficiency has turned out to be a complex issue. This paper contributes in two ways. First, the model presented in this paper establishes that dynamic inefficiency is not a necessary condition for deterministic bubbles in a stochastic economy. Second, a simulation shows that although bubbles are unable to persist in the stochastic steady state, they can still cure overaccumulation of capital for a time long enough to cover agents relevant time horizon.     

THE POLITICAL ECONOMY OF ENVIRONMENTAL POLICY WITH OVERLAPPING GENERATIONS

A two‐sector overlapping generations model illuminates the intergenerational effects of a tax that protects an environmental stock. A traded asset capitalizes the economic returns to future tax‐induced environmental improvements, benefiting the current asset owners, the old generation. Absent a transfer, the tax harms the young generation by decreasing their real wage. Future generations benefit from the tax‐induced improvement in environmental stock. The principal intergenerational conflict arising from the tax is between generations alive at the time society imposes the policy, not between generations alive at different times. A Pareto‐improving tax can be implemented under various political economy settings.     

Altruism,fertility, and the value of children: Health policy evaluation and intergenerational welfare

This paper accounts for the value of children and future generations in the evaluation of health policies. This is achieved through the incorporation of altruism and fertility in a “value of life” type of framework. We are able to express adults' willingness to pay for changes in child mortality and also to incorporate the welfare of future generations in the evaluation of current policies. Our model clarifies a series of puzzles from the literature on the “value of life” and on intergenerational welfare comparisons. We show that, by incorporating altruism and fertility into the analysis of the recent U.S. experience, the estimated welfare gain of a young adult from reductions in mortality easily doubles.     

资产价格泡沫研究述评:实验金融学视角

本文从实验金融学的视角介绍了资产泡沫最新的定义和分类,阐述了投机性泡沫、理性泡沫与非理性泡沫之间的区别和联系,着重从信息对称、信息不对称、有限套利泡沫、异质信念和实验金融五个方面系统评述了资产价格泡沫理论的发展历程和新进展,指出该领域进一步的研究方向和中国开展资产价格泡沫研究的重要意义。研究表明,随着现代金融学的高速发展,学界对资产泡沫的研究日益深入。特别是非理性和实验金融学视角的引入,突破了传统金融框架的束缚,为这一课题研究带来了新的认知和理解。即便如此,目前仍无法根除资产泡沫产生的可能性。很多相关问题,如资产泡沫产生的时间和根本原因,仍然等待着学者们去探索和研究。