An analysis of the conditions for the validity of Modigliani-Miller Theorem with incomplete markets

Summary In this paper we investigate the consequences of the firms' financial decisions in the framework of a perfectly competitive general equilibrium model with incomplete markets. When markets are complete or there are no derivative securities (such as options, forwards or futures) written on the firms' shares, these decisions are irrelevant. This result reaffirms and qualifies the original claim by Modigliani and Miller. On the other hand, if markets are incomplete, we show that in the presence of any type of derivative security a change in the capital structure of a firm will modify, generically, both the real equilibrium allocation and the value of the firm. The reason is that the payoff of the derivative securities is affected in a non-linear way by changes in the firm's financial policy; thus the set of the agents' insurance opportunities is also modified.The paper is a revised version of chapter 1 of my Ph.D. dissertation at Cambridge University. I wish to thank F. H. Hahn and H. M. Polemarchakis for their encouragement and very useful discussions. I am also grateful to J. Detemple, S. E. Satchell, S. Schaefer, P. Siconolfi, R. Stapleton, M. Subrahmanyam and three anonymous referees, as well as to participants at seminars at Cambridge, Columbia, EUI, Bocconi, USC, the R.E.S. Conference in Nottingham and the 6th World Congress of the Econometric Society in Barcelona for helpful comments. The usual disclaimer applies.     

Intuitionistic fuzzy sets in questionnaire analysis

Fuzzy sets represent an extension of the concept of set, used to mathematically model veiled and indefinite concepts, such as those of youth, poverty, customer satisfaction and so on. Fuzzy theory introduces a membership function, expressing the degree of membership of the elements to a set. Intuitionistic fuzzy sets and hesitant fuzzy sets are two extensions of the theory of fuzzy sets, in which non-membership degrees and hesitations expressed by a set of experts are, respectively, introduced. In this paper, we apply intuitionistic fuzzy sets to questionnaire analysis, with a focus on the construction of membership, non-membership and uncertainty functions. We also suggest the possibility of considering intuitionistic hesitant fuzzy sets as a valuable theoretical framework. We apply these models to the evaluation of a Public Administration and we assess our results through a sensitivity analysis.     

Gini’s transvariation analysis: an application on financial crises in developing countries

The damage and the recurrence of financial crises have increased the concern of investors and policymakers on one hand and the interest of macroeconomists on the other. This paper presents an original non parametric methodology, whose aim is to give a very intuitive and rigorous method for variable selection in order to analyse financial crises. Transvariation analysis compares the distributions of two different groups of countries (sound and distressed) with respect to a single macroeconomic variable and selects the indicators on the basis of a low transvariation probability index. The current account deficit to GDP ratio, differently from other studies on financial crises, seems to be a suitable variable in discriminating distressed countries from sound ones, and the case of Argentina and Turkey confirms this finding.     

Risk sharing and retrading in incomplete markets

At a competitive equilibrium of an incomplete-markets economy agents’ marginal valuations for the tradable assets are equalized ex-ante. We characterize the finest partition of the state space conditional on which this equality holds for any economy. This leads naturally to a necessary and sufficient condition on information that would induce agents to retrade, if such information was to become publicly available after the initial round of trade.     

Risk management and finance along value chains of Small Island Developing States. Evidence from the Caribbean and the Pacific

The paper analyses agricultural risks and risk management in selected Small Island Developing States which are part of the African Caribbean Pacific country group. Focus is on the value chains of fruits, vegetables and spices. A survey was conducted in Grenada, Jamaica, Fiji and Vanuatu, aimed at identifying sources of risk which are most important to value chain stakeholders; the nature and quality of existing and potential risk management mechanisms; and the possibility of enhancing them in view of improving the functioning of the value chains. The sample included farmers, processors, traders, retailers, extension agents, Government officials and private services providers. Results reveal limited ability to handle price and production variability, due to lack of both horizontal and vertical co-ordination along value chains, reduced use of support services, notably credit and underinvestment in equipment. In addition, lack of demand contributes to make insurance markets incomplete and characterised by undersupply or lack of customised products. Promoting light forms of vertical and horizontal co-ordination, such as production contracts and producers’ associations, as well as value chain-based credit and finance may address some of the issues highlighted.     

The use of organized commodity markets to manage food import price instability and risk

The article explores the possibility of insuring the price risks of wheat and maize imports of low‐income food‐deficit countries (LIFDCs). Optimal strategies for an importing agent, who hedges with futures and options are derived, based on the objective of minimizing the unpredictability of import bills. Ex post simulations for a set of LIFDCs are run on wheat and maize imports hedged with futures and options in the Chicago Board of Trade, to explore the extent to which hedging reduces the unpredictability in import bills. Simulations encompass both periods of normal price behavior, as well as the period of global upheaval that occurred in 2007 and 2008. Results show that hedging with futures alone affords agents considerable opportunities for reducing import cost unpredictability, and the same holds with options, albeit, to a lesser extent. However, during the recent price spike of 2007–2008, hedging with options would have increased the unpredictability of some countries’ maize import bills, due to the combination of erratic import patterns and pronounced market uncertainty.     

Disaggregation of excess demand and comparative statics with incomplete markets and nominal assets

Summary. We prove that locally, Walras' law and homogeneity characterize the structure of market excess demand functions when financial markets are incomplete and assets' returns are nominal. The method of proof is substantially different from all existing arguments as the properties of individual demand are also different. We show that this result has important implications and is part of a more general result that excess demand is an essentially arbitrary function not just of prices, but also of the exogenous parameters of the economy as asset returns, preferences, and endowments. Thus locally the equilibrium manifold, relating equilibrium prices to these parameters has also no structure. Received: September 17, 1996; revised version: November 7, 1997     

The breakdown of the IS–LM synthesis: implications for post-Keynesian economic theory

The monetarist and the new classical economics attack routed the IS–LM version of Keynesian theory and the large scale econometric models from the centre of macroeconomic research. However monetarism and the new classical economics were more successful as a critique of the IS–LM orthodoxy than as a basis for fruitful research and policy analysis.

Post-Keynesian economists also attack the IS–LM orthodoxy, mainly because it misspecified ‘… the economic society in which we actually live’. Post-Keynesians that emphasized financial and labour markets argued that properties of the real world economy made instability normal results ofmarket interactions.

The vacuum in main line theory that developed as the shortcomings of monetarism became evident led to a revival of interest in basic Keynesian propositions. This has spawned what is now labeled a new Keynesian economics. New Keynesian economists conform to the modeling standards set by the new classical rational expectations school but claim to get Keynesian results. To a degree these results are compatible with propositions of post-Keynesian economics.

It is suggested that a convergence between the new and the post-Keynesian economics can be expected, and the result is likely to be fruitful.     

On the Social Desirability of Patents for Sequential Innovations in a Vertically Differentiated Market

We consider a market for vertically differentiated goods where firms enter over time, after having developed innovations characterised by different quality levels. We show that patent height and length interact to determine the ultimate emergence of duopoly. In general, imposing quality improvements on later entrants entails the persistence of monopoly, while a duopoly equilibrium emerges when the second innovator is allowed to produce a sufficiently inferior quality and the patent protection granted to the first innovator is not too long-lasting.     

A case-control study on risk factors of domestic accidents in an elderly population

The aim of this study was to evaluate the combined influence of several lifestyle, health and housing factors in the occurrence of home injuries (HIs) among the elderly. The subjects were recruited from 10 hospitals in Rome, Italy. This study is a paired case-control study. Cases included subjects, aged 65-85 years, who visited the Emergency Department for an HI and were subsequently hospitalised (15 September 2004-30 June 2005). Controls were the subjects of the same gender, age (±3 years) and area of residence of cases. A conditional logistic regression model was used for analysing the variables obtained. In this study, we enrolled 107 hospitalised cases. It was found that the living room was the place where 33% of the accidents occurred. Eighty-seven per cent of the accidents were falls, and 33% of the accidents were the immediate consequence of sudden malaise. One-half of the cases reported one or more leg fractures. The variables that were independently associated with HI were poor household illumination, poor emotional status, regular physical activities and housekeeping activities. We conclude that this study shows the areas of intervention to target HI prevention activities.