Designing social security - a portfolio choice approach

Public social security systems may provide diversification of risks to individuals’ life-time income. Capturing that a pay-as-you-go system (paygo) may be considered as a “quasi-asset”, we study the optimal size of the paygo system as well as the optimal split between funded and unfunded pension saving by means of a theoretical portfolio choice framework. A low-yielding paygo system can benefit individuals if it contributes to hedge other risks to their lifetime resources. Numerical calculations indicate that optimal social security systems should be at least partly paygo financed in many economies. The optimal magnitude of the paygo system depends on the specified risk concept as well as the stochastic properties of stock market returns and implicit paygo-returns.     

Efficient markets and Bayes’ rule

Summary. A series of financial anomalies motivated the development of new theories that modify the rational expectations ideal. Two possibilities have been systematically explored. The literature on behavioral finance relaxes the assumption that agents form beliefs according to the laws of probability and assume, instead, that simpler heuristic rules are used. Another stream of the literature assumes that agents process information according to Bayes rule, but do not posses sufficient information to know the true data generating process. In this paper, Bayesian and Behavioral agents coexist and trade in a standard dynamic asset pricing model. A long-standing conjecture is demonstrated. It is shown that, under suitable assumptions, Bayesian agents drive Behavioral, non-Bayesian agents out of the market. Hence, asset prices are eventually determined under the Bayesian paradigm.Received: 3 June 2004, Revised: 17 September 2004, JEL Classification Numbers: D83.Preliminary versions have circulated under the titles Markets Favor Bayesian Models and Market Selection of Empirical Models under Limited Information. I thank Larry Blume, David Easley, Larry Epstein, Armando Gomes, Bruce Hansen, Lars Hansen, Richard Kihlstrom, Grace Koo, George Mailath, Werner Ploberger, Andrew Postlewaite and Shakeeb Khan for useful comments. I also thank participants at the NBER GE meetings, Evolutionary Finance conference in Zurich, Latin American Meetings of the Econometric Society, Stanford Institute for Theoretical Economics, the Instituto de Matematica Pura e Aplicada, the theory seminar at Brown, Chicago, Harvard-MIT, Minnesota, Penn and Wisconsin. I gratefully acknowledge the financial support from the National Science Foundation Grant SES 0109650.     

The extension of social security coverage in developing countries

We study the dynamic general equilibrium effects of introducing a social pension program to elderly informal sector workers in developing countries who lack formal risk sharing mechanisms against income and longevity risks. To this end, we formulate a stochastic dynamic general equilibrium model that incorporates defining features of developing countries: a large informal sector, private transfers as an informal safety net, and a non-universal social security system. We find that the extension of retirement benefits to informal sector workers results in efficiency losses due to adverse effects on capital accumulation and the allocation of resources across formal and informal sectors. Despite these losses recipients of social pensions experience welfare gains as the positive insurance effects attributed to the extension of a social insurance system dominate. The welfare gains crucially depend on the skill distribution, private intra-family transfers and the specific tax used to finance the expansion.     

Disability benefit microsimulation models in the Netherlands

Disability rates in the Netherlands used to be among the highest in the world. In 2002 the number of disability recipients approached one million. However, since then the number of disability cases has dropped remarkably due to a number of policy changes, the last of which being the new 2006 disability insurance scheme. On the other hand, in recent years the number of beneficiaries in the special scheme dedicated to the young handicapped has increased rapidly.     

Age-Dependent Taxation and the Optimal Retirement Benefit Formula

Abstract. This paper presents a comprehensive view of lifetime taxation including both explicit taxation through the general tax system and implicit taxation via the retirement benefit formula. Differences in productivity between individuals are unobservable, which provides a rationale for the use of distortionary taxes. It is shown that the optimal structure of age-dependent taxation can be characterized by a generalized Ramsey formula. Furthermore, the paper derives the optimal retirement benefit formula in the presence of the general tax system and examines the compatibility with the financial stability of the pension system.     

Differential mortality and social security

Abstract This paper studies the normative problem of redistribution between individuals who differ in their lifespans. We discuss aspects related to the objective function and argue that aversion to multiperiod inequality should be taken into account. Then, we study the properties of the social optimum both with full information and with asymmetric information. We highlight the role of aversion to multiperiod inequality and show that it has substantial consequences on the design of Social Security schemes. In particular, we show that for a low (resp. high) aversion to multiperiod inequality, a negative (resp. positive) implicit tax rate on continued activity is desirable.     

Strategic environmental policy and the accumulation of knowledge

In dealing with a transnational pollutant-emitting duopoly welfare-maximising policy makers face two negative externalities: imperfect competition and unpriced emissions. Strategic environmental policy models show that these externalities involve a trade-off between reducing pollution and allowing for rent-seeking of the respective firm. This dilemma usually results in a suboptimal internalisation of the negative externality emerging from emissions. Indeed, the conventional model setup includes an R&D stage that enables the firms to mitigate regulation costs. But the typical one period configuration ignores that R&D expenditures create knowledge capital which is, due to its inherent cumulativeness, also effective in following periods. Our model analyses the established trade-off in a two period setting and therefore allows for an investigation of intertemporal knowledge accumulation. We find that the intertemporal effects provide an incentive for a policy maker to set a higher tax rate compared to a one-period setup which lessens the magnitude of the suboptimal internalisation of emissions. Under certain conditions even a tax rate above the Pigouvian level is possible in period 1.     

Changing International Financial Architecture: Growing Chinese Influence?

It is often said that the 21st century will be the Asian century. Based on population and gross domestic product projections, it certainly looks as if this will be so. Will the existing international financial institutions give more voices, votes, and top positions to Asia? Or will Asia create its own institutions that would rival the old architecture? This present paper argues, first, that China, and possibly India, will be in a position to be so influential that the international financial architecture may have to go through significant changes. Second, the three large crises in the last 20 years have made Asian countries more confident that they can manage capital flows by accumulating large foreign reserves and by adopting sound macrofinancial policies. After 2009, China started to push various initiatives that will amount to creating its own sphere of influence with new regional institutions in the future.