Intertemporal substitution, risk aversion and ambiguity aversion

Summary. This paper axiomatizes a form of recursive utility on consumption processes that permits a role for ambiguity as well as risk. The model has two prominent special cases: (i) the recursive model of risk preference due to Kreps and Porteus [18]; and (ii) an intertemporal version of multiple-priors utility due to Epstein and Schneider [8]. The generalization presented here permits a three-way separation of intertemporal substitution, risk aversion and ambiguity aversion.Received: 5 August 2003, Revised: 12 March 2004, JEL Classification Numbers: D80, D81, D90.I am grateful to Larry Epstein for his guidance and invaluable advice, and to a referee for helpful comments and suggestions.     

Comprehensive analysis of market conditions in the foreign exchange market

We investigate quotation and transaction activities in the foreign exchange market for every week during the period of June 2007 to December 2010. A scaling relationship between the mean values of number of quotations (or number of transactions) for various currency pairs and the corresponding standard deviations holds for a majority of the weeks. However, the scaling breaks in some time intervals, which is related to the emergence of market shocks. There is a monotonous relationship between values of scaling indices and global averages of currency pair cross-correlations when both quantities are observed for various window lengths ?? t.     

Computing equilibrium bond prices in the Vayanos-Vila model

We develop tools for computing equilibrium bond prices for the discrete-time version of the Vayanos–Vila (2009) model. With the maturity structure included in pricing factors, factor loadings for equilibrium bond yields depends critically on parameters describing maturity structure dynamics and other model parameters. An illustrative example shows that the effect on the yield curve of a supply shock originating in a given maturity, although hump-shaped around the originating maturity, is to change yields broadly across all maturities.     

Designing the optimal public pension system

This paper uses a two‐period overlapping generations model in order to provide a theoretical design for the optimal public pension system based on a partial equilibrium analysis. Household preferences depend on two periods' consumption and leisure and are positively homogeneous of degree m with respect to consumption in the working and retired periods. We present characteristic features of the optimal public pension system in this paper. First, differences in the population growth rate do not affect the large/small relation between the optimal net lifetime burden rates of generations. Second, we present the optimal public pension system explicitly if m < 1 and m ≠ 0. Third, the difference between the market time‐preference rate and the social time‐preference rate provides a crucial insight into the optimal burden rate of each generation.     

Forecasting welfare caseloads: The case of the Japanese public assistance program

Forecasting welfare caseloads has grown in importance in Japan because of their recent rapid increase. Given that the forecasting literature on welfare caseloads only focuses on US cases and utilizes limited classes of forecasting models, this study employs multiple alternative methods in order to forecast Japanese welfare caseloads and compare forecasting performances. In pseudo real-time forecasting, VAR and forecast combinations tend to outperform the other methods investigated. In real-time forecasting, however, a simple version of forecast combinations seems to perform better than the remaining models, predicting that welfare caseloads in Japan will surpass 1.7 million by the beginning of 2016, an approximately 20% increase in five years from the beginning of 2011.     

Regret aversion and opportunity dependence

This paper provides an axiomatic model of decision making under uncertainty in which the decision maker is driven by anticipated ex post regrets. Our model allows both regret aversion and likelihood judgement over states to coexist. Also, we characterize two special cases, minimax regret with multiple priors that generalizes Savage's minimax regret, and a smooth model of regret aversion.     

Information infrastructure: Who builds broadband networks?

This paper examines the essential difference between the U.S. and Japan, when one considers information infrastructure. There are seven perception gaps between the U.S. and Japan concerning Information Infrastructure policies. These gaps must be understood in order to compare the countries' governmental policies in this area. In looking at the present circumstances, the essential question to answer concerns who is to build, own and operate the network(s) of the infrastructure. Liberalization is certain to be a central factor in the ongoing telecommunications debates. Now that customers have had a taste of the liberalized market-place, the movement toward more open markets will be difficult to stop. When considering options, it is necessary to pay close attention to standardized network access and the increasingly important role software plays. These issues are causing us to take a new approach to the traditional role played by regulators. They also force a closer look at the appropriate structure of utility companies. This paper addresses the above issues in hopes of stimulating dialog on the new telecommunications infrastructure paradigm.     

Quasi-stationary cardinal utility and present bias

This note gives an axiomatic foundation for utility exhibiting quasi-geometric discounting. In addition, it introduces a wider class of utility functions satisfying weakened stationarity, called quasi-stationary utility. Both are established as von Neumann-Morgenstern utility indices in a model of risk preference.