Rationalizable expectations and sunspot equilibria in an overlapping-generations economy

There are two theories for the treatment of market uncertainty: rationalizable expectations and sunspot equilibria. This paper shows how the game-theoretic solution concept of rationalizable expectations can be applied to an overlapping-generations exchange economy. Some general properties of these equilibria are discussed. It is shown that rationalizable-expectations equilibria are the predictions yielded by considering sunspot equilibria in which probability beliefs may differ across individuals. This result allows for a new interpretation of sunspot equilibria and helps to understand their relevance.     

Consumption habits in an overlapping-generations model

This paper introduces consumption habits in the Blanchard (1985) overlapping-generations model. It shows that steady-state capital and consumption are higher if individuals have habits than otherwise. Moreover, “inward habits” lead to higher steady-state capital and consumption compared to “outward habits.”     

Heterogeneous producers facing common shocks: An overlapping-generations example

An analytically tractable model of a competitive, full-information economy is provided in which, for some parameter values, entry and exit over the course of the business cycle is concentrated among small firms. This model is intended to make the logical point that the relatively high sensitivity of small firms to business-cycle fluctuations does not necessarily indicate the presence of informational or incentive constraints in financial markets.     

Existence of equilibrium in an overlapping-generations model with government debt

The Diamond overlapping generations (OLG) model with government debt has been widely utilized in economics, but the existence of the steady-state equilibrium is either assumed or illustrated numerically. This paper provides easily checkable conditions for the existence and uniqueness of steady-state equilibrium in this model. By checking the first derivatives of the production and utility functions and their interactions, we can determine whether the model has a nontrivial equilibrium or not. We show that the level of government debt, production technology, individual preference, and the growth rate are important for the existence of equilibrium. If government debt exceeds a certain level, equilibrium will not exist. Given technology, preference, and the growth rate, the upper-bounds of the government debt-output ratio in equilibrium can be determined based on our results.     

Fertility and mortality changes in an overlapping-generations model with realistic demography

Many overlapping-generations models assume only working and retirement stages and are “not capable of representing the most basic feature of the human economic life cycle: that it begins and ends with periods of dependency, separated by a long intermediate period of consuming less than is produced” (Bommier and Lee, 2003). To examine the economic consequences of fertility and mortality changes in a common framework, we incorporate realistic demographic features into a continuous-time overlapping-generations model with childhood, adulthood and retirement stages. Using parameter values appropriate for industrial countries (such as the USA), we find that a fertility increase and a mortality decline, while both causing a rise in the population growth rate, have opposite effects on capital accumulation. We also consider simultaneous fertility and mortality changes, and find that the effect on capital accumulation of a mortality change dominates that of a fertility change.     

Intergenerational natural-capital equality in an overlapping-generations model with logistic regeneration

Following Mourmouras [Scandinavian Journal of Economics 93 (1991): 585–591], in a Diamond [American Economic Review 55 (1965): 1126–1150] type overlapping-generations model with renewable natural resources a competitive path of manmade capital accumulation exists which meets the sustainability criterion of intergenerational natural-capital equ(al)ity (= sustainable growth). The alleged compatibility of decentralized optimization with natural-capital sustainability is appealing, but the rel-evance of this compatibility result is questionable: the growth factor of the renewable natural resource is assumed to be independent of the resource stock. Employing instead a nonlinear (logistic) regeneration function, this paper reconsiders Mourmouras' compatibility statement in another natural environment. It is shown that only under a certain complex relationship between the parameters of the utility, production, and natural-growth function does a nontrivial stationary state exist which is saddle-point stable. It exhibits by definition intergenerational natural-capital equality, but the non-linear setting precludes in general, natural-capital equality across generations on the growth path towards the stationary state.     

An overlapping-generations model with search

Search is embedded in an overlapping-generations model. The young participate in a centralized market, and then are matched in pairs in a decentralized market. The old only participate in the centralized market. If the buyer's bargaining power in pairwise trade is close to unity and if the old are risk averse, then the golden-rule rate of money transfer is positive. Such risk aversion, the pairwise meetings, and dependence of the young's saving on the rate of return are necessary for this result.     

Existence of steady – state equium in an overlapping-generations model with production

Summary This paper establishes an existence theorem of a non-trivial (positive capital stock) steady-state equilibrium in Diamond's (1965) overlapping-generations model with production by employing the steady-state consumption curve introduced in Ihori (1978). The assumptions on preferences and production technologies that ensure the existence of a nontrivial steadystate equilibrium are separated from each other, unlike in Galor and Ryder (1989). We also provide two simple examples which illustrate the importance of two conditions in the theorem.Detailed comments by Tomoichi Shinotsuka and the referees of the journal were quite helpful. We also thank Marcus Berliant, Mark Bus, John H. Boyd III, Ban Chuan Cheah, Rajat Deb, Jim Dolmas, Oded Galor, Greg Huffman, Toshihiro Ihori, Radhika Lahiri, Lionel McKenzie, Arundhati Sen, and the seminar participants at the Midwest Mathematical Economics Conference in Ann Abor and at University of Rochester. The second author gratefully acknowledges the financial supports from the European Community Human Capital Mobility Program.     

Heterogeneous capital and misintermediation

A perennial problem of financial markets is that of maturity mismatch, or misintermediation, a situation in which financial intermediaries fund long-term, illiquid loans with short-term liabilities. A previous theory concludes that misintermediation can be responsible for business cycles and yields procyclical behavior of surprises in real interest rates. This paper proposes a finite horizon structural model with the introduction of heterogeneous capital to formalize and develop that theory. An extended model with labor as well as a “harvesting” technology further investigates the impact of misintermediation on real factor prices. The model implied relationship between unanticipated changes in real interest rates and real outputs over time is examined in a subsequent empirical study, which provides preliminary evidence consistent with the hypothesis of misintermediation.     

Political economy of taxation in an overlapping-generations economy

This paper analyzes the effects of intergenerational conflict on capital and labor income tax rates, transfers, and government spending in a model of multidimensional policy choice. The different nature of tax liabilities for the young and the old can explain why the old receive large gross lump-sum transfers through social security, while the young receive little or none. A natural link also emerges between the size of the government as a provider of public goods and the magnitude of transfers that the same government will implement.     

Heterogeneous expectations in the foreign exchange market

In this study a regime-switching approach is applied to estimate the chartist and fundamentalist (c&f) exchange rate model originally proposed by Frankel and Froot (1986). The c&f model is tested against alternative regime-switching specifications applying likelihood ratio tests. Nested atheoretical models like the popular segmented trends model suggested by Engel and Hamilton (1990) are rejected in favour of the multi-agent model. Our findings turned out to be relatively robust when assessing the models sub-sample estimates and out-of-sample performance.JEL Classification: F31, F37, G12, G15 Correspondence to: S. Reitz     

Heterogeneous expectations and the distribution of wealth

This study examines the extent to which heterogeneity of expectations affects wealth distribution, through the use of a standard heterogeneous agent model with uninsured idiosyncratic risk and aggregate uncertainty. A simple stylized model of heterogeneous expectations is considered to demonstrate that the impact of expectations’ heterogeneity on wealth inequality depends nonlinearly on the level and persistence of expectations’ dispersion. It is also shown that the heterogeneity of expectations generated by the empirically validated learning-from-experience model (Malmendier, Nagel, Q J Econ 2016) has a moderate but ambiguous impact on the distribution of wealth. The effect is sensitive to the calibration of the macroeconomic and learning parts of the model.     

Markov rational expectations equilibria in an overlapping generations model

In this paper, we analyze rational expectations equilibrium paths in a stochastic overlapping generations model. The work presented here builds on results of S. E. Spear (J. Econ. Theory 35 (1985), 251–275), where is is shown that in a model with multiple goods and time non-separable preferences, a stochastic steady state equilibrium will generically fail to exist. A stochastic steady state is defined as an equilibrium in which the stochastic process of endogenously determined variables is measure isomorphic to the exogenous process driving the model. In this paper, we establish the existence of non-steady state equilibria and provide a characterization of their stochastic properties.     

On the equivalence between the overlapping-generations model and cyclical general-equilibrium models

We show that equilibrium cycles in an overlapping-generations model are equivalent to asymmetric equilibria in a general-equilibrium model. We use this equivalence to find equilibrium cycles in the overlapping-generations model with two and three generations, respectively. For the example with two generations we show that for certain parameter values cycles of all periods occur.     

Human capital and economic growth in an overlapping generations model

The paper describes an aggregative optimal growth model, the essential features of which are that individuals are mortal and obtain their labor skill through educational training. The process of human capital formation is described by an education function which relates the pass rate to the educational expenditure per student. Two alternative scenarios, private and public education regimes, are separately investigated. Under the decentralized education regime, risk-neutral individuals borrow to finance their education when young. Under the centralized education regime, the cost of education is financed by taxes imposed on the workers in the economy, and the central government maximizes a long-term social target function. The equilibria of both regimes are analyzed and various comparative static results derived. It is shown that educational investment in a decentralized equilibrium is higher than that in the centralized steady state. We also establish that there exists a time discount rate at which or above which the decentralized per capita consumption exceeds that of the centralized steady state whereas for time rates of discount sufficiently near the population growth rate, the above result will be reversed.     

Facts and distortions in an endogenous growth model with physical capital, human capital and varieties

This article studies a model with physical and human capital accumulation and varieties. The model includes several distortions: duplication effects, spillovers, creative destruction, surplus appropriability, and an erosion effect. We show that the duplication effect in R&D is essential to make the model replicate several stylized facts linked with R&D. We evaluate the distance to the optimal solution, comparing the strength of each distortion.     

Intertemporal separability in overlapping-generations models

In a pure exchange overlapping-generations model with many goods, but a single consumer with preferences separable between two periods of life, there are (generically) finitely many equilibria in which money has no value. If money has value, then (generically) there is at most one dimension of indeterminacy. This property does not generalize to a model with many consumers and general preferences. It is shown why a separable representative consumer implies such strong conclusions. It is also shown that the absence of income effects leads to similar results.     

Global indeterminacy in an endogenous-growth model with public capital

This paper studies the patterns of growth in an endogenous-growth model where the labor supply is endogenous and sustained growth arises because the services derived from public capital increase the economic productivity. It is assumed that these services are congested by the number of households in the economy but they are not congested by the units of time that each household devotes to work. With this assumption, the dynamic equilibrium exhibits multiple balanced-growth paths, local and global indeterminacy, and limit cycles under some plausible fiscal policies. Our analysis points out that a large lump-sum tax is a necessary condition to obtain this complex equilibrium dynamic behavior.