On the equivalence of the static and dynamic asset allocation problems

A classic dynamic asset allocation problem optimizes the expected final-time utility of wealth, for an individual who can invest in a risky stock and a risk-free bond, trading continuously in time. Recently, several authors considered the corresponding static asset allocation problem in which the individual cannot trade but can invest in options as well as the underlying. The optimal static strategy can never do better than the optimal dynamic one. Surprisingly, however, for some market models the two approaches are equivalent. When this happens the static strategy is clearly preferable, since it avoids any impact of market frictions. This paper examines the question: when, exactly, are the static and dynamic approaches equivalent? We give an easily tested necessary and sufficient condition, and many non-trivial examples. Our analysis assumes that the stock follows a scalar diffusion process, and uses the completeness of the resulting market model. A simple special case is when the drift and volatility depend only on time; then the two approaches are equivalent precisely if (μ (t)? r)/σ²(t) is constant. This is not the Sharpe ratio or the market price of risk, but rather a nondimensional ratio of excess return to squared volatility that arises naturally in portfolio optimization problems.     

How Do Switching Costs Affect Market Concentration and Prices in Network Industries?

I investigate the effects of switching costs on the market outcome in network industries using a dynamic duopoly model of price competition in the presence of an outside option. I find that the role of switching costs depends on network effects and the outside option. Without a viable outside option, high switching costs can neutralize the tendency towards high market concentration associated with network effects, but with a viable outside option, switching costs increase market concentration. Furthermore, switching costs lower prices if network effects are modest and there exists a viable outside option, but generally raise prices otherwise.     

Sacrifice Ratios: Some lessons from EMU countries, 1960-2001

This paper estimates the sacrifice ratios based on the Phillips curve. Using annual data, we estimate individual and common sacrifice ratios for EMU countries. In addition, we test whether the sacrifice ratio is stable for the whole period, which includes years of both high and low inflation rates, such as those observed after the European integration.     

Is the US fiscal deficit sustainable?: A fractionally integrated approach

In this paper, we examine if sustainability of the US fiscal deficit holds by means of studying the univariate properties of the difference between expenditures and public revenues using a methodology based on fractional processes. Furthermore, we incorporate the possibility of structural breaks in the deficit process. The results show that when allowing for a break in the mid-1970s, the public deficit in the US is an I(d) process with the fractional integration parameter d being slightly less than unity, implying that the fiscal deficit is mean reverting, and thus, sustainable, though the adjustment process towards equilibrium will take a very long time.     

Persistence,Long Memory,and Unit Roots in Commodity Prices

This article investigates the degree of persistence in several weekly and monthly agricultural prices (corn, soybeans, barrow and gilts, and milk) using long memory (fractional integration) techniques. The results indicate mean reversion (i.e., orders of integration smaller than one) in some of the agricultural prices like corn, milk, and barrow and gilts when the disturbances are autocorrelated. Further, we examine the stability across time in the degree of dependence, and the results indicate that the fractional differencing parameters have not remained constant across time. When we take into account a structural break we find that during the first subsamples, the series are stationary though highly persistent, with orders of integration close to 0 and with large autoregressive coefficients. However, for the periods after the break, the series seem to be nonstationary I(1). Dans le présent article, nous avons étudié le degré de persistance des prix hebdomadaires et mensuels de plusieurs produits agricoles (maïs, soja, castrats et cochettes, lait) à l’aide de tests de mémoire longue (intégration fractionnaire). Nos résultats indiquent une stationnarité (c.‐à.‐d. des ordres d’intégration inférieurs à un) des prix de certains produits agricoles, tels que le maïs, le lait, les castrats et cochettes, lorsque les perturbations sont autocorrélées. Nous avons également étudié la stabilité du degré de dépendance à travers le temps, et nos résultats indiquent que les paramètres de différenciation fractionnaire ne sont pas demeurés constants. Lorsque nous avons tenu compte d’une rupture structurelle, nous avons trouvé que dans les premiers sous‐échantillons, les séries étaient stationnaires quoique très persistantes, avec des ordres d’intégration près de 0 et d’importants coefficients d’autorégression. Dans le cas des périodes suivant la rupture, les séries semblaient non stationnaires I(1).     

Financial effects of an uncertain change in VAT rates in the EU

The paper analyses how close relationships to banks influence a firm’s choice of financing its debt through publicly marketed bonds or bank loans. It is shown that large Japanese firms use less bank debt, if banks own shares in the firm or bank employees are members of the firm’s board. This result supports a theoretical framework, where banks are able to control agency problems associated with debt. Firms use bank loans in order to be monitored, which enables them to access cheaper bond finance. Closer bank–firm relationships facilitate monitoring for the bank and reduce therefore the need for bank finance.     

The dynamics of environmental innovations: three stylised trajectories of clean technology

In this article, we explore the dynamics of environmental innovations developed by firms to comply with environmental regulations. Our analysis is based on a micro-simulation model of industrial dynamics. The question arises: how do firms competing in the same industry deal with environmental issues without altering their productive efficiency or the performance of the product? We focus on clean technology which seeks to combine environmental and productive dimensions by way of innovation offsets. Our simulations show that an innovative strategy based on a good balance between environmental and productive dimensions takes more time to develop and needs to address a ‘competence destroying effect’. Finally, we study favourable conditions for the development of this type of clean technology and draw some policy implications.     

Real convergence in some Central and Eastern European countries

This article examines the real convergence hypothesis in some Central and East European countries (both towards the German and the US economies) by means of using time series techniques during the period 1950 to 2003. No evidence is found of real convergence for the whole period. However, when one allows for structural breaks, evidence is found of a catch-up process during the 1990s to 2003 period for Poland, the Czech Republic and Hungary towards Germany and only for Poland towards the US economy.     

Gender,Honor, and Aggregate Fertility

This article examines the tension between population‐level and individual‐level interests regarding childbearing, from Malthus's concern for overpopulation to the contemporary issue of son preference, and argues for an understanding of individual‐level interests that distinguishes parents from households. In making this distinction, we draw attention to how gender norms can play an important role in shaping reproductive interests. Survey data and previous work show a wealth of differences in the number of children men and women would like to have, and in their behaviors toward the children they have. We argue not that gender norms cause women to want more children than men, but that they cause women to want children more, for reasons that include time spent with children, old‐age support, women's proscribed opportunities for achieving social standing, and the relationship in many contexts between honorable female adulthood and bearing children at the right time and under the right circumstances. We further argue that a just and effective population policy must consider fertility outcomes at multiple scales, including that of the welfare of individual women.