Diversity and relative arbitrage in equity markets

An equity market is called diverse if no single stock is ever allowed to dominate the entire market in terms of relative capitalization. In the context of the standard Itô-process model initiated by Samuelson (1965) we formulate this property (and the allied, successively weaker notions of weak diversity and asymptotic weak diversity) in precise terms. We show that diversity is possible to achieve, but delicate. Several examples are provided which illustrate these notions and show that weakly-diverse markets contain relative arbitrage opportunities: it is possible to outperform or underperform such markets over any given time-horizon. The existence of this type of relative arbitrage does not interfere with the development of contingent claim valuation, and has consequences for the pricing of long-term warrants and for put-call parity. Several open questions are suggested for further study.Received: January 2004, Mathematics Subject Classification (2000): 60H10, 91B28; 60J55JEL Classification: G10We are grateful for the helpful remarks offered by seminar audiences at Columbia, Yale, Princeton, the Sloan School of MIT, Boston University, the Mathematical Institute in Oberwolfach, and the Universities of Athens, Connecticut/Storrs and Texas/Austin. Special thanks go to Professors Jérôme Detemple, Julien Hugonnier, Ralf Korn, Andrew Lo, Mark Lowenstein and Steven Shreve. We are also indebted to Dr. Adrian Banner for a number of discussions that helped sharpen our thinking about these problems, and to the referees and editors for suggestions that improved the exposition. A significant part of this work was completed in the spring semester of 2002, while the second author was on sabbatical leave at the Cowles Foundation for Research in Economics, Yale University. He is grateful to the Foundation for its hospitality.     

Fear of Floating and Pegging: A Simultaneous Choice Model of De Jure and De Facto Exchange Rate Regimes in Developing Countries

We present an analysis of the determinants of de jure and de facto exchange rate regimes based on a panel probit model with simultaneous equations. The model is estimated using simulation-based maximum likelihood methods. The empirical results suggest a triangular structure of the model such that the choice of de facto regimes depends on the choice of de jure regimes but not vice versa. This gives rise to a novel interpretation of regime discrepancies.

Capital buffer and credit‐risk adjustments in Islamic and conventional banks

The main purpose of this article is to empirically investigate the interactions between changes in capital buffer and changes in credit risk, using panel data of Islamic and conventional banks located in the Middle East and North Africa (MENA) region over the period 1999–2016. A negative two‐way relationship between the changes in capital buffer and the changes in credit risk is found for the two types of banks, that is, banks tend to decrease their capital buffers in response to an increase in risk exposure and limit their risky activities in response to an increase in their capital buffers. Dividing our period of study into three subperiods to assess the effect of the last financial crisis 2007–08 on the adjustment process, we point out the negative bidirectional relationship between the changes in capital buffer and the changes in credit risk of the two types of banks is present for the three subperiods except the case of conventional banks during the precrisis period. Moreover, we provide evidence that Islamic banks adjust their capital buffer in response to the changes in credit risk regardless of the existence or not of a deposit insurance scheme. In contrast, the negative two‐way relationship between the changes in capital buffer and the changes in credit risk in conventional banks is found only in countries without deposit insurance schemes.     

Do jobs follow people or people follow jobs? A meta-analysis of Carlino–Mills studies

Do jobs follow people or people follow jobs? A meta-analysis of Carlino–Mills studies. Spatial Economic Analysis. This study examines the classic question as to whether ‘jobs follow people’ or ‘people follow jobs’ by performing a meta-analysis of 321 results from 64 Carlino–Mills studies. It is found that the results are highly divergent, but that more results point towards ‘jobs following people’ than towards ‘people following jobs’. When it comes to the reasons for the variation in results, we find that the results are mostly shaped by the geographical location, spatial resolution, and population and employment characteristics present in the data, as well as by the model’s specification, its functional form and the spatial weight matrix specification.     

On dividends in the phase–type dual risk model

The dual risk model assumes that the surplus of a company decreases at a constant rate over time, and grows by means of upward jumps which occur at random times with random sizes. In the present work, we study the dual risk renewal model when the waiting times are phase-type distributed. Using the roots of the fundamental and the generalized Lundberg’s equations, we get expressions for the ruin probability and the Laplace transform of the time of ruin for an arbitrary single gain distribution. Then, we address the calculation of expected discounted future dividends particularly when the individual common gains follow a phase-type distribution. We further show that the optimal dividend barrier does not depend on the initial reserve. As far as the roots of the Lundberg equations and the time of ruin are concerned, we address the existing formulae in the corresponding Sparre-Andersen insurance risk model for the first hitting time, and we generalize them to cover also the situations where we have multiple roots. We do that working a new approach and technique, approach we also use for working the dividends, unlike others, it can be also applied for every situation.     

Farmers’ crop insurance perception and participation decisions: empirical evidence from Hunan,China

The measurement of risk perception and risk attitudes, and their link to actual risk behaviors have been extensively discussed. However, the potential impact of perception of risk management instruments on the decision to use those instruments has rarely been addressed. This article hypothesizes that the degree of perception of insurance contracts and participation decisions could have substantial mutual influence depending on the development of the market. An empirical work is carried out based on a survey of data for paddy rice farmers in Hunan Province, China. It shows that the sampled farmers’ crop insurance perception was surprisingly low despite years of pilot programs and tens of billions of expenditure in government subsidies. The result of simultaneous equations model indicates that crop insurance perception and participation are simultaneously determined and mutually improving. Moreover, empirical evidence indicates that the impact of crop insurance participation on perception is slightly stronger than that of perception on participation, and thus provides weak evidence of a ‘learning-by-doing’ stage in China at present. Together with evidence of substantial local disparities in perception, implications for the Chinese government in further cultivating the crop and rural insurance market are discussed.     

Operations in banking: the service quality and effects on satisfaction and loyalty

This paper studies the service quality provided by the banks. The objectives are (i) to identify which aspects of the transactions carried out by the banks are important for the service quality perceived by the customers, taking into account some aspects that are sometimes ignored (online channels) and (ii) to observe how service quality influences customer satisfaction and how customer satisfaction affects the loyalty towards the bank. Using a factor analysis, the research identifies the operative, physical, new technologies and human factors. Next, using structural equations models with AMOS, the results show an influence of the operative aspects and the new technologies on service quality, as well as the confirmation of quality as a precedent to customer satisfaction, and how such satisfaction influences on customer's loyalty towards the bank.     

Modeling population dynamics and economic growth as competing species: An application to CO2 global emissions

Since the beginning of the last century the world is experiencing an important demographic transition, which will probably impact on economic growth. Many demographers and social scientists are trying to understand the key drivers of such transition as well as its profound implications. A correct understanding will help to predict other important trends of the world primary energy demand and the carbon emission to the atmosphere, which may be leading to an important climate change. This paper proposes a set of coupled differential equations to describe the changes of population, gross domestic product, primary energy consumption and carbon emissions, modeled as competing species as in Lotka-Volterra prey-predator relations. The predator-prey model is well known in the biological, ecological and environmental literature and has also been applied successfully in other fields. This model proposes a new and simple conceptual explanation of the interactions and feedbacks among the principal driving forces leading to the present transition. The estimated results for the temporal evolution of world population, gross domestic product, primary energy consumption and carbon emissions are calculated from year 1850 to year 2150. The calculated scenarios are in good agreement with common world data and projections for the next 100 years.     

直线法线式方程在建筑施工放样中的应用

建筑物轴线的放样主要是计算出各轴线的交点的坐标,然后通过全站仪极坐标放样的方法定出轴线交点的位置。由于建筑物坐标系和测量坐标系不同,应先通过坐标转换将建筑物轴线交点转换为测量指标,本文提出无需进行坐标转换,而是通过建立建筑方格网主轴线法线式直线方程,并以此推求出建筑物轴线的法线式直线方程,进而通过解方程组求得交点坐标。     

Enhancing effects of manufacturing flexibility through operational absorptive capacity and operational ambidexterity

A large body of research investigates how manufacturing flexibility in uncertain environments leads to firm performance, with mixed results. The mixed findings could be due to differences across firms in terms of the capabilities to acquire, assimilate, and transform knowledge and to simultaneously pursue both the exploitation of existing operational capabilities and the exploration for new operational capabilities. Building on the literature that suggests that manufacturing flexibility mediates the relationship between environmental uncertainty and firm performance, we explore the applicability of two organizational learning contingencies to the operations environment: operational absorptive capability and operational ambidexterity. Absorptive capacity enables the recognition and assimilation of new knowledge. Ambidexterity determines whether this knowledge will be applied for both exploration and exploitation. Using a sample of 852 manufacturing firms, we find that environmental uncertainty affects firm performance directly and indirectly through manufacturing flexibility. Furthermore, both operational absorptive capacity and operational ambidexterity moderate the relationship between environmental uncertainty and manufacturing flexibility and the relationship between manufacturing flexibility and firm performance. Theoretical and practical implications are discussed.