BEHAVIORAL PORTFOLIO SELECTION: ASYMPTOTICS AND STABILITY ALONG A SEQUENCE OF MODELS

We consider a sequence of financial markets that converges weakly in a suitable sense and maximize a behavioral preference functional in each market. For expected concave utilities, it is well known that the maximal expected utilities and the corresponding final positions converge to the corresponding quantities in the limit model. We prove similar results for nonconcave utilities and distorted expectations as employed in behavioral finance, and we illustrate by a counterexample that these results require a stronger notion of convergence of the underlying models compared to the concave utility maximization. We use the results to analyze the stability of behavioral portfolio selection problems and to provide numerically tractable methods to solve such problems in complete continuous‐time models.     

全球海运铁矿石市场承压解析与行业影响

世界钢产量峰期出现在2000年以后,其高速增长动力主要来源于中国,而中国铁矿石原矿资源禀赋的劣势,愈发刺激了中国对国际海运铁矿石的需求,致使中国铁矿石需求的对外依存度较高,与此同时,作为铁矿石纯进口国的中国难以主导铁矿石定价权。2011年国际铁矿石市场正值高位运行,大部分铁矿石生产商在高价驱使下,选择大幅增加投资成本扩建产能,海运铁矿石市场供需基本面开始倒转。2015年以来,铁矿石中国到岸价大幅下跌,铁矿石生产巨头由于低廉的现金生产成本也只能勉强盈利或者维持在盈亏平衡线附近,高成本矿被实质性挤压出局。而美国量化宽松政策收紧乃至退出,导致金融流动性降低,进一步巩固了全球铁矿石市场"供强需弱"的格局。由于国内高成本铁矿项目的退出,中国铁矿石需求对外依存度将会进一步升高。     

Dynamics of agricultural land use change in Kerala: a policy and social-ecological perspective

Land-use change is a phenomenon highlighting significant shifts in human interaction with the natural environment. Different patterns of agriculture and a trend towards non-agricultural land use challenge the sustainability of farming systems. This study aims to identify the causes of changes in land use and cropping patterns, with a special focus on paddy, the staple crop in Asia. In the case of Wayanad, a district in Kerala, South India, we argue for an interdisciplinary analysis of rapid land-use change to unpack the multiple dimensions of sustainability: economic, ecological and social factors, aggregating up to 70% reduction in the area under paddy by 2010. The results rest on empirical field research, participatory rural appraisals and stakeholder workshops conducted during the 4-year period from 2010 to 2013, along with state- and district-level data covering the 1983–2011 period. Reduced economic viability, labour shortages and population pressure on land are the major drivers for the transformation of paddy fields to other land uses. Changes in land use and agrarian structure reflect not only the livelihood strategies adopted by farmers in response to these drivers, but also the impacts of unintended policy idiosyncrasies. At a more fundamental level, they are the consequences of policy conflicts and inadequate sectoral integration of policies and implementation strategies.     

Solving the income fluctuation problem with unbounded rewards

This paper studies the income fluctuation problem without imposing bounds on utility, assets, income or consumption. We prove that the Coleman operator is a contraction mapping over the natural class of candidate consumption policies when endowed with a metric that evaluates consumption differences in terms of marginal utility. We show that this metric is complete, and that the fixed point of the operator coincides with the unique optimal policy. As a consequence, even in this unbounded setting, policy function iteration always converges to the optimal policy at a geometric rate.     

Technology fusion: Identification and analysis of the drivers of technology convergence using patent data

The concepts of technology convergence or technology fusion describe the phenomenon of technology overlap. Despite evidence of the higher value associated to interdisciplinary research and cross-industry innovation, few studies have investigated the characteristics of technology fusion based on patent data. This study identifies new cases of convergence relying on the International Patent Classification (IPC) of patents filed at the European Patent Office between 1991 and 2007: the first occurrence of a patent incorporating a combination of IPC subclasses signals a new instance of fusion. Duration models are employed to investigate the impact of field level characteristics derived from patent bibliometrics on the likelihood of identifying a new fusion. The results show that merges are more frequent if the focal technology fields are closely related (based on a higher number of cross citations), are characterized by wide technological scope, and are the result of an inter-firm collaboration. In contrast to previous findings, the results show that the more complex the technologies involved, the less the likelihood of their convergence or fusion. The correlation between fusion likelihood and the characteristics of the merging fields could help managers and policymakers to predict the emergence of new technology areas.     

基于风险中性路径概率的三叉树期权定价模型

树方法是给经典期权进行定价的非常实用的数值方法,目前最流行的是二叉树模型。三叉树定价模型作为二叉树的一个扩展,其同样是在风险中性概率的基础上给经典期权进行定价,并且可以通过MATLAB实现。相比于二叉树而言,三叉树模型的定价结果具有更好的收敛性。除此之外,用三叉树模型对影响期权价格的一些因素进行敏感性分析,可以验证该模型的合理性。     

Market integration and convergence to the Law of One Price: evidence from the European car market

This paper exploits the unique case of European market integration to investigate the relationship between integration and price convergence in international markets. Using a panel data set of car prices, we examine how the process of integration has affected cross-country price dispersion in Europe. We find surprisingly strong evidence of convergence towards both the absolute and the relative versions of the Law of One Price (LOOP). Our analysis illuminates the main sources of segmentation in international markets and suggests the type of institutional changes that can successfully reduce it.     

国内保险集团战略趋同的成因与对策

近年来,我国保险业始终保持了又好又快发展的良好势头,取得了令人瞩目的成绩。随着保险业的不断发展,一批具有较强实力的保险集团开始出现,当竞争进入到一定阶段之际,各保险集团间的发展战略开始有一定程度的趋同倾向。占据市场主导地位的保险集团在战略上趋同,将使得集团间的竞争更加复杂和激烈,也将对保险业的未来发展产生深远影响。本文旨在探讨这种现象的成因、影响,以及保险集团对此应采取的一些对策。     

中国铁路交通发展对沿线城市经济增长趋同的影响

以1997—2011年中国6次铁路提速和高铁开通为背景,在β趋同模型中加入用可达性度量的铁路交通发展因素,并用频次加权平均旅行时间衡量可达性,从全国、区域和城市3个空间层次分析了中国铁路交通发展对铁路沿线城市经济增长趋同的影响。结果显示:铁路交通发展对全国、东部地区、东北地区以及提速铁路沿线城市的经济增长的β趋同均有促进作用,对西部地区铁路沿线城市经济增长的β趋同有阻碍作用,而铁路交通发展对非提速铁路沿线城市经济增长的β趋同的影响甚微,对中部地区铁路沿线城市经济增长的β趋同的影响不确定。     

2002—2011年中国新型城市化空间格局与收敛性分析

根据新型城市化的内涵,从经济、社会、生态、城乡和城市现代等方面,构建中国新型城市化综合评价指标体系,运用熵值法,对2002—2011年中国31个省份进行测评。同时,运用空间分析工具和计量模型,考察了中国新型城市化水平的空间格局和收敛性。结果显示:1全国新型城市化水平呈现逐年上升的趋势,但东部、中部和西部的整体水平差异较大。2在空间格局分析上,各省域新型城市化水平在空间上存在显著的正相关,地域总体格局呈现三级梯度分布的趋势;新型城市化主要是靠长三角和珠三角两大城市群拉动的。3在收敛分析上,新型城市化存在显著的收敛性,应用合理空间模型(SEM)能加快收敛的时间。4在收敛检验方面,引入变量大大提高了模型的拟合程度,并且城镇人口比重最大。研究认为,要加强户籍制度改革,破除城乡二元结构,推动中国城市化健康发展。