An existence result for discontinuous games

We introduce a notion of upper semicontinuity, weak upper semicontinuity, and show that it, together with a weak form of payoff security, is enough to guarantee the existence of Nash equilibria in compact, quasiconcave normal form games. We show that our result generalizes the pure strategy existence theorem of Dasgupta and Maskin [P. Dasgupta, E. Maskin, The existence of equilibrium in discontinuous economic games, I: Theory, Rev. Econ. Stud. 53 (1986) 1-26] and that it is neither implied nor does it imply the existence theorems of Baye, Tian, and Zhou [M. Baye, G. Tian, J. Zhou, Characterizations of the existence of equilibria in games with discontinuous and non-quasiconcave payoffs, Rev. Econ. Stud. 60 (1993) 935-948] and Reny [P. Reny, On the existence of pure and mixed strategy equilibria in discontinuous games, Econometrica 67 (1999) 1029-1056]. Furthermore, we show that an equilibrium may fail to exist when, while maintaining weak payoff security, weak upper semicontinuity is weakened to reciprocal upper semicontinuity.     

Pricing executive stock options under employment shocks

We obtain explicit expressions for the subjective, objective and market value of perpetual executive stock options (ESOs) under exogenous employment shocks driven by an independent Poisson process. Previously, we obtain the executive's optimal exercise policy from the subjective valuation that is necessary for the objective one, or fair value. The perpetual ESO is compared with the true finite maturity ESO finding that the approximation is reasonably good. To illustrate the usefulness of the objective valuation for accounting purposes, we analyze the statistical distribution of the fair value when there is uncertainty about the employment shock intensity. Finally, the role of ESOs in the design of executives’ incentives is also discussed.     

Housing affordability during the urban transition in Spain

During the decades prior to the Civil War, Spain experienced a rapid process of urbanization, which was accompanied by the demographic transition and sizeable rural–urban migrations. This article investigates how urban housing markets reacted to these far‐reaching changes, which increased demand for dwellings. To this end, this study employs a new hedonic index of real housing prices and constructs a cross‐regional panel dataset of rents and housing price fundamentals. This new evidence indicates that rents were not a significant financial burden on low‐income families and, hence, housing was affordable for the working classes. The article also shows that families’ access to new homes was facilitated by a sizeable growth in the housing supply. Substantial investments in urban infrastructure and the institutional framework enabled the construction of new homes at affordable prices. Our results suggest that housing problems were not as pervasive during the urban transition as the literature often seems to claim.     

Tangent Lévy market models

In this paper, we introduce a new class of models for the time evolution of the prices of call options of all strikes and maturities. We capture the information contained in the option prices in the density of some time-inhomogeneous Lévy measure (an alternative to the implied volatility surface), and we set this static code-book in motion by means of stochastic dynamics of It?’s type in a function space, creating what we call a tangent Lévy model. We then provide the consistency conditions, namely, we show that the call prices produced by a given dynamic code-book (dynamic Lévy density) coincide with the conditional expectations of the respective payoffs if and only if certain restrictions on the dynamics of the code-book are satisfied (including a drift condition à la HJM). We then provide an existence result, which allows us to construct a large class of tangent Lévy models, and describe a specific example for the sake of illustration.     

Environmental Impact,Export Intensity,and Productivity Interactions: An Empirical Index Analysis of the Agri‐Food Industry in Spain

Recent studies have focused on how exports affect environmental performance or vice versa, while others have concentrated on the productivity of export‐oriented firms. The objective of the present paper is to provide a simultaneous analysis on the aforementioned relationships. The approach followed is a composite equation model in which export performance and productivity components, including an environmental indicator, are endogenously determined, taking as reference exporting firms of the food industry in Southeast Spain, for the period 1994–2006. The results show positive interactions among export intensity, firm efficiency, and environmental productivity, also suggesting that the consideration of endogeneity may enhance the findings of analyses on these issues. Des études récentes se sont concentrées sur les effets des exportations sur la performance environnementale ou vice‐versa, tandis que d’autres se sont concentrées sur la productivité des entreprises à vocation exportatrice. Le présent article vise à fournir une analyse simultanée des liens précités. Nous avons utilisé un modèle àéquations multiples dans lequel les éléments liés à la performance des exportations et à la productivité, y compris un indicateur environnemental, sont déterminés de façon endogène, en prenant comme référence des entreprises agroalimentaires à vocation exportatrice situées dans le sud‐est de l’Espagne, durant la période de 1994 à 2006. Les résultats montrent des interactions positives entre l’intensité des exportations, l’efficacité des entreprises et la productivité environnementale, ce qui autorise à penser que l’endogénéité pourrait améliorer les résultats des analyses sur ces points.     

Audit committees’ social capital and financial reporting quality

We draw on social capital theory to examine the relationship between audit committee (AC) members’ social capital and financial reporting quality. Using US data for the period 2001–2010, our results suggest that non-AC directors’ social capital does not appear to be relevant to financial reporting quality. As far as AC members are concerned, our findings show a negative relationship between their social capital and financial reporting quality, suggesting a ‘dark side’ to social capital. Specifically, we find that sitting in multiple ACs (centrality) has a negative impact on reporting quality only for those AC members designated as financial experts. When other proxies for social capital are considered (connectedness, brokerage position and strong ties), our results show that the quality of financial reporting significantly decreases with the social capital of non-financial experts sitting in the AC. We contribute to prior research by: (i) relying on social capital theory, which is widely neglected in accounting research, (ii) using multiple metrics to capture the complex dimensions of social capital, and (iii) discriminating between the effects of financial and non-financial experts’ social capital on reporting quality. Our results suggest policy-makers might wish to limit financial experts’ multiple directorships as well as assess the actual contribution of non-financial experts to AC effectiveness.     

Interacting particle systems for the computation of rare credit portfolio losses

In this paper, we introduce the use of interacting particle systems in the computation of probabilities of simultaneous defaults in large credit portfolios. The method can be applied to compute small historical as well as risk-neutral probabilities. It only requires that the model be based on a background Markov chain for which a simulation algorithm is available. We use the strategy developed by Del Moral and Garnier in (Ann. Appl. Probab. 15:2496–2534, 2005) for the estimation of random walk rare events probabilities. For the purpose of illustration, we consider a discrete-time version of a first passage model for default. We use a structural model with stochastic volatility, and we demonstrate the efficiency of our method in situations where importance sampling is not possible or numerically unstable.