Comment on "Ellsberg's two-color experiment, portfolio inertia and ambiguity"

In the setting of Ellsberg's two-color experiment, Mukerji and Tallon (2003) claim, without relying on particular representations, that ambiguity-averse behavior implies subjective portfolio inertia. In this note, we point out using a counterexample that their axioms are not enough to establish the result. We fill in the gap in their argument using additional axioms and argue that these axioms are of their own interest in that they behaviorally separate two prominent models of ambiguity: the maximin expected utility and smooth ambiguity models.     

The Viability of Fixed Exchange Rate Commitments: Does Politics Matter? A Theoretical and Empirical Investigation

This article studies the connection between political instability and the sustainability of an exchange rate regime. A model based on the credibility of monetary policy shows that political unrest should be correlated with the adoption of flexible exchange rates. That intuition is tested using various measures of political instability on a panel of 125 countries between 1980 and 1994.     

The Demand for Food Products: An Analysis of Interpurchase Times and Purchased Quantities

In this paper we study household purchase behaviour of storable food products. An inventory model is developed in which the household chooses an optimal stock level of the product. Storage of the product is costly, there is a fixed cost per purchase occasion, and the market price is sometimes discounted because of price promotions. We show that the optimal purchase policy is an s , S policy. The model is used to derive predictions on the correlations between interpurchase times and purchased quantities on the one hand, and prices on the other. These predictions are empirically verified using consumer panel data.     

Externalities, consumption constraints and regular economies

We consider a general model of pure exchange economies with consumption externalities. Households may have different consumption sets and each consumption set is described by a function called the possibility function. Utility and possibility functions depend on the consumptions of all households. Showing by means of an example that basic assumptions are not enough to guarantee generic regularity, we provide sufficient conditions for generic regularity in the space of endowments and possibility functions.     

Ambiguity aversion and the absence of indexed debt

Summary. Following the seminal works of Schmeidler (1989), Gilboa and Schmeidler (1989), roughly put, an agents subjective beliefs are said to be ambiguous if the beliefs may not be represented by a unique probability distribution, in the standard Bayesian fashion, but instead by a set of probabilities. An ambiguity averse decision maker evaluates an act by the minimum expected value that may be associated with it. In spite of wide and long-standing support among economists for indexation of loan contracts there has been relatively little use of indexation, except in situations of extremely high inflation. The object of this paper is to provide a (theoretical) explanation for this puzzling phenomenon based on the hypothesis that economic agents are ambiguity averse. The paper considers a general equilibrium model based on Magill and Quinzii (1997) with ambiguity averse agents, where both nominal and indexed bond contracts are available for trade and all relevant prices are determined endogenously. We obtain conditions which prompt an endogenous cessation of trade in indexed bonds: i.e., conditions under which there is no trade in indexed bonds in any equilibrium; only nominal bonds are traded.Received: 7 April 2003, Revised: 8 March 2004, JEL Classification Numbers: D81, E31, D52, E44.Correspondence to: Sujoy MukerjiWe thank seminar members at Birkbeck, Oxford, Paris I, Southampton and Tel Aviv, the audience at the 00 European Workshop on General Equilibrium Theory, and especially, E.Dekel, I. Gilboa, D. Schmeidler and A. Pauzner for helpful comments. The first author acknowledges financial assistance from an Economic and Social Research Council of U.K. Research Fellowship (# R000 27 1065). The second author thanks financial support from the French Ministry of Research (Action Concertée Incitative).     

Heterogeneous Expectations,Short Sales Regulation,and the Risk-Return Relationship

This paper examines, in a Canadian context, the effect of short sales regulation on the risk-return relationship. It shows that, theoretically, the opportunity cost induced by short sales regulation is positively related to the dispersion of agents' beliefs and negatively related to the security's liquidity level. The model is tested over the sixty-month period from January 1985 through December 1989. All the 13,079 observations are pooled into a time series cross-sectional model. The results corroborate that a negative linear relationship links expected risky asset returns and the divergence of agents' beliefs. This negative relationship is consistent with the presence of opportunity costs resulting from short sales regulation when return beliefs are heterogeneous. However, the negative relationship between security returns and dispersion of beliefs is essentially confined to illiquid securities, that is, those monitored by a small number of analysts.     

The new challenges of organizing intellectual property in complex industries: A discussion based on the case of Thales

The defense industries in France and elsewhere have, in recent years, undergone important technological, organizational and institutional changes that have profoundly altered their architectures. These changes have introduced a new division of labor bringing new opportunities for interaction leading to the creation of additional assets. In this context, the issue of protecting innovations and their exploitation has become central. Managing intellectual property rights (IPR) requires industrial groups to draw on additional capabilities. This article analyzes these evolutions and focuses in particular on the new organizational arrangements that have accompanied them. Using the case of Thales, which in 2005 outsourced its Intellectual Property (IP), we answer questions such as: why should IP be outsourced; how should the outsourcing of IP activities be organized; and, how should capabilities involved in this new organizational arrangement be managed. These issues lie at the center of this research and illustrate new challenges inherent to in-house and outsourced IPR management strategies.     

The real exchange rate and the structure of aggregate production

This paper proposes a new, production theory approach to the determination of the real exchange rate, which is defined as the relative price of traded to nontraded goods as is common in the international trade literature. Using a Translog real GDI function that describes the aggregate technology of an open economy as a starting point, the real exchange rate can be formally derived as a function of domestic excess savings, the terms of trade, relative factor endowments and technological progress. Empirical results for Switzerland suggest that the main drivers of the real exchange rate are the terms of trade, followed by relative factor endowments. Contrary to conventional wisdom, the Balassa-Samuelson effect does not seem to play a significant role in explaining the long-term real appreciation of the Swiss franc.     

Does securities regulation constrain small business finance? An empirical analysis

In November 2001, the Canadian province of Ontario amended the private placement regulations considerably to facilitate access to equity financing by small and medium sized enterprises (SMEs). To determine the extent to which securities regulation is an effective constraint on financing of growth corporations, we analyze issue activity before and after this change took effect. We note an increase in the number of issues, but only a slight increase in the total amounts raised on the private market following the reform. The average size of the issues has thus decreased. Some of the observed changes can be traced to concurrent events, namely the burst of the technology bubble and the strong increase in the prices of natural resources, which represent a major sector in Canada. When we control for various factors that influence issue activity, we observe a statistically significant effect only on the number of issues by closed corporations, which seems to originate from the non-resource companies. These results do not rule out the conclusion that the reform eased the issue of small amounts of money by private companies. However, our results do not confirm the argument that securities regulation is a major constraint to small business finance.