OLG Model Research Articles

Study on the Impact of China’s Pension Insurance System on the Savings Rate of Urban Residents Based on the Preventive Saving Perspective

In the context of population aging, the study of the impact of the pension insurance system on the savings behavior of urban residents can help reduce preventive savings, increase current consumption, and promote the healthy development of the economy. This study constructs a two-period OLG model of the pension insurance system based on the preventive saving perspective using urban panel data of 31 provinces from 2002 to 2021 and conducts empirical analysis through the systematic generalized method of moments. The results show that the pension insurance participation rate was positively correlated with the savings rate, while the pension replacement rate was negatively correlated with the savings rate, and this effect varied significantly across income levels and different levels of aging. Increased participation in high-income areas promoted savings, while increased pension replacement rates in low-income areas reduced savings. The positive correlation between participation rates and savings rates was more pronounced in regions with higher levels of aging, while the opposite was true in regions with lower levels of aging. In addition, the negative correlation between pension replacement ratios and savings rates was particularly pronounced in high-aging regions.

When Interest Rates Go Low, Should Public Debt Go High?

Is deficit finance free when real borrowing rates are routinely lower than growth rates? Specifically, can the government make all generations better off by perpetually taking from the young and giving to the old? We study this in stochastic closed- and open-economy OLG models. Unfortunately, Pareto gains are predicted only for implausible calibrations. Even then, the gains reflect improved inter-generational risk sharing, improved international risk sharing, and beggaring thy neighbor—not intergenerational redistribution, per se. As we show, theoretically and quantitatively, low government borrowing rates suggest state-contingent bilateral transfers between generations––not unconditional, unilateral redistribution from future to current generations. (JEL E43, E62, F41, H55, H63)

Population aging, pensions, informality and labor market frictions in Lebanon. Reforms and policy choices

We evaluate the effects of population aging on the macroeconomic evolution of the Lebanese economy and the financial sustainability of its major pension schemes. We use an OLG model with labor market frictions as in de la Croix et al. (2013). Individuals are differentiated by their origin, age, gender, and education and choose the sector of activity, which implies that the size of the informal sector is endogenous. We assess the long-run implications of population aging and show that the public sector pension scheme is unsustainable. In contrast, the private sector scheme is insufficient to ensure decent living standards for the elderly. Finally, we evaluate the effects of two pension reforms. We first propose a mix of measures that guarantee the sustainability of the public sector scheme. Then, we evaluate the impact of the pension reform introduced in December 2023 and of an alternative reform aiming at increasing the size of the private sector scheme to improve the living standards for the elderly.

Imperfect competition in the banking sector and economic instability

We study the impact of competition in the banking sector on the emergence of endogenous cycles driven by self-fulling volatile expectations. We consider an OLG model with two sectors and two household types: workers, who consume and work when young and save through bank deposits; and entrepreneurs, who seek bank loans to finance current consumption and to invest in a productive technology that transforms the consumption good into capital. When old, entrepreneurs rent this capital to firms, who produce the consumption good using capital and labor. All markets are perfectly competitive, except the loans market where banks compete à la Cournot under free entry and exit.In the absence of externalities in the capital producing technology, more competition in the banking sector promotes the emergence of local indeterminacy and sunspots fluctuations. In contrast, under constant social returns to scale in the capital producing technology, bank market power alone triggers the emergence of local indeterminacy. With increasing social returns to scale, both market power and externalities facilitate the emergence of local indeterminacy. Additionally, when banks have market power, steady state multiplicity may emerge, opening the way to global indeterminacy and fluctuations.

Grandparental childcare, family allowances and retirement policies

AbstractThe paper uses an OLG model to study the interaction between policies designed to ensure the sustainability of the pension system, i.e. child allowances and pensions policies, and grandparental childcare. We find that the rise in grandparenting negatively affects the elderly labour supply hampering the impact of pension policies designed to raise the retirement age and lengthen working lives. Then, we introduce child allowances and find that the impact of child allowances on the fertility rate is influenced by the efficiency of grandparenting in reducing child-rearing costs. Child benefits have a positive impact on fertility only if grandparenting is not very effective at reducing childcare costs. This suggests that the role of grandparents in various countries may partly explain the inconsistency in empirical evidence on the relationship between child benefits and fertility rates. The study also finds that child benefits have a positive impact on the elderly labour supply when grandparenting is efficient.

Stochastic overlapping generations with non-convex budget sets

Non-convexities and discrete choices have become important modeling tools in modern macroeconomics. Unfortunately, the existence of competitive equilibria in the presence of such non-convexities is not always ensured, and most results on the existence of equilibrium that can be found in the literature do not directly apply to models used in applications.In this paper, we explain the three main difficulties one encounters when proving the existence and give simple sufficient conditions for the existence of competitive equilibria in stochastic OLG models with non-convex budget sets. We also give sufficient conditions for the existence of approximate equilibria that are recursive in the natural state.

You have been terminated: robots, work, and taxation

We present a three sector OLG model with a homogeneous output good that is produced with traditional or robot technology. The traditional sector produces with labor and capital, whereas the modern sector employs robots instead of labor. Robots and workers are modeled as perfect substitutes to investigate whether economic policy under the harshest assumptions is able to prevent the ascent of a robotized economy. While we find that the transition is inevitable, higher taxes on robots and revenues can slow down the process. We also that the economy will switch from an exogenous growth model based on TFP to an endogenous growth model due to constant returns with respect to reproducible factors of production as it becomes fully robotized.

Human capital and pensions with endogenous fertility and retirement

AbstractWe study an OLG model with child policies and a PAYG pension with endogenous retirement and fertility. The result of the planned economy is compared to the decentralized competitive equilibrium deriving optimal policies. We show that in the presence of a PAYG pension system, the optimal policy mix includes an education subsidy and a subsidy for the supply of labor in old age. Fertility should be taxed or incentivized depending on whether there is full or partial retirement, and on the parameters. We focus on the parameter reflecting the deterioration of human capital and show that a child tax may be required.

Environmental Governance, Public Health Expenditure, and Economic Growth: Analysis in an OLG Model.

This article studies the relationship between environmental governance, public health expenditure, and economic growth by introducing human health status into a three-period overlapping generation dynamic general equilibrium (OLG-DGE) model and conducting a policy simulation analysis in a Chinese scenario. The main findings are generalized as follows: (i) The increase in pollution emissions per unit of output will not only lead to the deterioration of public health but also hinder long-term economic growth, while the efficiency of pollution control will improve health and output per labor unit; (ii) Although levying environmental tax will improve health status and life expectancy, it has a non-linear impact on pollution emissions and output per labor unit, which means that there are trade-offs among environmental governance, public health improvement, and economic output; and (iii) Although the increase in the proportion of public health expenditure will improve health status, its impact on life expectancy and economic output is affected by the level of environmental tax. Only when the environmental tax rate is relatively low, will increasing the proportion of public health expenditure extend life expectancy and output per labor unit.

Losers amongst the Losers:: The welfare effects of the great recession across cohorts

This paper studies the effect of deep recessions on intergenerational inequality by quantifying the welfare effects on households at different phases of the life cycle. Deep recessionary episodes are characterized by large declines in the prices of real and financial assets and in employment. The former levies high welfare costs on older households who own financial wealth, the latter determines labour income losses and destroys the human capital of younger cohorts, lowering their productivity. The paper extends previous analyses in the literature by including permanent labour income losses in an OLG model calibrated to match the Great Recession. The analysis shows that younger households lose more than double of all other living cohorts, as younger household become unemployed and experience a decline in their future income. The dynamics of households’ consumption and portfolio composition between 2007 and 2013 in the US are consistent with the predictions of the model.

Heterogeneous expectations and equilibria selection in an evolutionary overlapping generations model

The way agents form their expectations, and which equilibria are consequently selected, are issues that come over macroeconomic growth models that study the transition between states characterized by different levels of capital. Existing theoretical works in this area have been mostly dominated by perfect foresight models although alternative expectations schemes have been proposed in the last decades. In the present paper we propose an OLG model with capital accumulation assuming that agents employ simple yet heterogeneous rules to forecast the future course of the interest rate and the real wage. The forecasting rules are selected according to an evolutionary mechanism that, on the basis of a fitness measure, evaluates the performance of the heuristics agents are currently adopting. We analytically show that, in the heterogeneous setting we consider, multiple equilibria are possible, but the evolutionary heuristic switching allows for a decrease in the number of possible steady states, drives their selection, and reduces the actual possibility that the economy might be locked into a poverty trap.

Public redistributive policies in general equilibrium: An application to Greece

We develop a general equilibrium OLG model of a small open economy to quantify the aggregate and distributional implications of a wide menu of public redistributive policies in a unified context. Inequality is driven by unequal parental conditions in financial and human capital. The model is calibrated and solved using fiscal data from Greece. Our aim is to search for public policies, targeted and non-targeted, that can reduce income inequality without damaging the macroeconomy and without worsening the public finances. Pareto-improving reforms that also reduce inequality include an increase in public education spending provided to all and an increase in the inheritance tax rate on financial wealth. At the other end, we identify reforms that may reduce inequality but make everybody worse off. Regarding cases in between, a switch to a fully funded public pension system is good for everybody although it is the rich-born that benefit more by moving to a more efficient macroeconomy.

Social security as Markov equilibrium in OLG models: Clarifications and some new insights

This paper studies the politico-economic sustainability of pay-as-you-go social security in OLG models under Markovian strategies as first studied by Forni (2005). Under logarithmic utility, the paper shows that equilibria with social security can only exist if the underlying economy is dynamically inefficient. The paper also derives the exact parametric conditions that allow for the existence of equilibria and shows that among all the admissible (arbitrary) constants that produce a Markov perfect equilibrium, the maximum constant in such set yields the only equilibrium that solves dynamic inefficiency.

Necessary and sufficient conditions for determinacy of asymptotically stationary equilibria in OLG models

We propose a criterion for verifying whether an equilibrium of an overlapping-generations model is amenable to local policy analysis, i.e., is determinate. The criterion is applicable for a generic set of parameters of the model, and in case of indeterminacy, it indicates the nature of the problem: multiplicity of equilibria or their absence for near-by parameters.The criterion can be applied to models with infinite past and future as well as to those with a truncated past. The baseline equilibrium is not required to be a steady state, and economic parameters, for example endowments, can change over time. However, asymptotically, the equilibrium should be stationary, though the two limiting paths at either end of the time-line do not have to be the same. If they are, conditions for local uniqueness of equilibrium are far more stringent for an economy with a truncated past as compared to its counterpart with an infinite past.We illustrate our main result using a text-book model with a single physical good and a two-period life-cycle. There, price growth paths that start at one steady state and end up at another constitute indeterminate equilibria for all parameters.

On the long-run fluctuations of inheritance in two-sector OLG models

This paper provides a long-run cycle perspective to explain the behavior of the annual flow of inheritance. Based on the low- and medium frequency properties of long time bequests series in Sweden, France, UK, and Germany, we explore the extent to which a two-sector Barro-type OLG model is consistent with such empirical regularities. As long as agents are sufficiently impatient and preferences are non-separable, we show that endogenous fluctuations are likely to occur through two mechanisms, which can generate independently or together either period-2 cycles or Hopf bifurcations. The first mechanism relies on the elasticity of intertemporal substitution or equivalently the sign of the cross-derivative of the utility function whereas the second rests on sectoral technologies through the sign of the capital intensity difference across two sectors. Furthermore, building on the quasi-palindromic nature of the degree-4 characteristic equation, we derive some meaningful sufficient conditions associated to the occurrence of complex roots and a Hopf bifurcation in a two-sector OLG model.

General equilibrium cryptocurrency pricing in an OLG model

We study the valorization of cryptocurrency in an overlapping generations model where agents have the choice between crypto- and central bank currency. We pay attention to three features of cryptocurrency: it is a risky asset (because of frauds and hacks), which one acquires by bearing transaction costs, and its supply reaches its upper limit in a finite time (e.g., Bitcoin). We consider both the standard case with linear–quadratic utility functions and the more general case where utility functions are not specified. We find that the effect of an increase in cryptocurrency on the currency prices depends on the transaction costs that individuals bear to get cryptocurrency. In particular, when these costs are convex non-increasing in the quantity of cryptocurrency, the cryptocurrency price may increase with this quantity. Otherwise, when the transaction costs are either increasing or concave non-increasing, the cryptocurrency price decreases with the quantity of cryptocurrency. We also show that the cryptocurrency and the central bank currency prices always move in opposite directions.

Social Security as Markov Equilibrium in OLG Models: Clarifications and New Insights

Social Security as Markov Equilibrium in OLG Models: Clarifications and New Insights

Financial Intermediation and Business Cycles in Two-Period Lived OLG Models

Financial Intermediation and Business Cycles in Two-Period Lived OLG Models

Market Power in Two-Period Lived OLG Models with Rational Expectations

Market Power in Two-Period Lived OLG Models with Rational Expectations

Efficient Risk Sharing and Financial Intermediation in Two-Period Lived OLG Models

Efficient Risk Sharing and Financial Intermediation in Two-Period Lived OLG Models