The mean-variance investment problem in a constrained financial market

This paper extends the mean-variance analysis and the two-fund separation theorem to a market with some constraints, such as, the incompleteness, prohibition of short-selling, and partial information, with stochastic interest rate, and with stochastic volatility for risky assets. By maximizing a quadratic utility of terminal wealth, we show that the efficient frontier for the problem is a straight line in the mean-standard-deviation diagram. The quadratic utility function exhibits mean-variance efficiency. Our results apply to portfolios of claims in a single period, multiperiod, and continuous time.     

Optimality conditions¶and bubbles in sequential economies¶and bounded relative risk-aversion

We provide specific qualifications in order that Kuhn–Tucker type Euler equations and transversality conditions at infinity hold in stochastic equilibrium models with heterogeneous agents and where assets are traded in sequential markets. It is not assumed that uncertainty is modeled as an event-tree structure or that preferences are necessarily bounded. We also describe an important class of preferences based on bounded relative risk aversion which yields relevant simplifications. Our results are used to establish conditions that rule out asset pricing bubbles. Specific examples of economies with bubbles are also discussed. Received: 28 January 2002 / Accepted: 19 July 2002 We are grateful to the editor and an anonymous referee for their valuable comments. This research was partially supported by MURST (Italy), National Group on “Nonlinear Dynamics and Stochastic Models in Economics and Finance”.     

Endogenous Growth and Negative Externalities

Received March 5, 2001; revised version received August 5, 2002 Published online: April 30, 2003     

Bayesian MCMC Mapping of Quantitative Trait Loci in a Half-sib Design: a Graphical Model Perspective

Graphical models provide a powerful and flexible approach to the analysis of complex problems in genetics. While task-specific software may be extremely efficient for any particular analysis, it is often difficult to adapt to new computational challenges. By viewing these genetic applications in a more general framework, many problems can be handled by essentially the same software. This is advantageous in an area where fast methodological development is essential. Once a method has been fully developed and tested, problem-specific software may then be required. The aim of this paper is to illustrate the potential use of a graphical model approach to genetic analyses by taking a very simple and well-understood problem by way of example.     

Inequality foundations of concentration measures: An application to the Hannah-Kay indices

The aim of this paper is to provide a connection between concentration and inequality. In particular, we show that the general entropy inequality indices are, among inequality measures, those consistent with the whole set of Hannah-Kay concentration indices. We isolate the inequality component underlying concentration measures, obtaining an explicit additive decomposition of the change in concentration into the change in its two components, i.e., inequality and the number of firms. This relationship proves to be valid for the whole set of Hannah-Kay concentration indices, and embodies as particular cases some others previously found in the literature. We are particularly grateful to Emilio Cerdá for helpful comments on the mathematical formulation of the paper. The second author also acknowledges support through the European Commission Project #ERBCHRXCT980248.     

Does a Switch of Budget Regimes Affect Investment and Managerial Discretion of State-Owned Enterprises? Evidence from Italian Firms

We investigate the investment decisions of Italian state-owned enterprises (SOEs) across budget constraint regimes and carry out a natural experiment that exploits a regime switch in 1987. Drawing on the theory of capital market imperfections, we apply an empirical framework for investment analysis to a panel of manufacturing SOEs in competitive industries. We identify parallels between SOEs and widely held, quoted companies afflicted by agency problems, managerial discretion, and overinvestment. We argue that, in the case of SOEs, the soft budget regime increases managerial discretion, facilitates collusion with vote-seeking politicians, and results in wasteful investment. Consistent with our predictions, we find that the regime switch disciplines SOE's investment behavior. Following a hardening of the budget constraint, managers lose discretion to indulge in collusion and overinvestment. J. Comp. Econ., June 2002 30(4), pp. 787–811. London School of Economics and Political Science, Houghton Street, London WC2A 2AE, United Kingdom; and CERIS–CNR, Institute for Economic Research on Firms and Growth, National Research Council, Via Avogadro, 8, 10121 Turin, Italy. © 2002 Association for Comparative Economic Studies. Published by Elsevier Science (USA). All rights reserved.Journal of Economic Literature Classification Numbers: E32, G31, G32, L32, M40.     

Intraday return and volatility relationships between the Ibex 35 spot and futures markets

This paper analyses the intraday lead-lag relationships between returns and volatilities in the Ibex 35 spot and futures markets. Using hourly data, we jointly analyze the interactions between markets, estimating a bivariate error correction model with GARCH perturbations which captures stochastically the presence of an intraday U-shaped curve for both spot and futures market volatility. Our findings show a bidirectional causal relationship between market volatilities, with a positive feedback. This two-way transmission of volatility is consistent with market prices evolving according to a long-run equilibrium relationship, and shocks affecting both markets in the same direction. Our empirical results also support a unidirectional cross interaction from futures to spot market returns. This pattern suggests that the futures market leads the spot market in order to incorporate the arrival of new information.     

Government Deficit, Public Investment, and Public Capital in the Transition to an Aging Japan

This paper examines the effects of government deficits, public investment, and public capital on welfare in the transition to an aging Japan by applying a simulated general equilibrium growth model. One of the main results of this paper is that targeting only high economic growth would mislead us as to economic policies, and that a policy to reduce future government deficits is most preferable for almost all generations, even though a cut in future deficits must be followed by a decrease in public investment, thus a decrease in public capital in the future. J. Japan. Int. Econ., December 2002, 16(4), pp. 462–491. Faculty of Economics, Shiga University, Japan; and Management School, Imperial College, United Kingdom. © 2002 Elsevier Science (USA).Journal of Economic Literature Classification Numbers: H55, H54, H62, C68, J10.     

Intra-Industry Reactions to Stock Split Announcements

We examine whether favorable information conveyed by stock split announcements transfers to nonsplitting firms within the same industry. On average, nonsplitting firms' shareholders experience positive and significant abnormal returns at the stock split announcements of their industry counterparts. In addition, industrywide and firm-specific characteristics are important determinants in explaining nonsplitting firms' stock returns. These firms' earnings increase significantly, and the earnings changes are positively related to the stock price reactions. Finally, we find no evidence that investors revise the value of nonsplitting firms because they anticipate a decline in earnings volatility.