Short sellers and insider trading profitability: A natural experiment

We examine the impact of short sellers on insider trading profitability using a natural experiment of a pilot program which relaxed short-selling constraints for randomly selected pilot stocks. We find that pilot firms experienced a significant decrease in insider trading profitability during the pilot program. The results are more pronounced for the pilot firms with poor information quality, and for the pilot firms without corporate restrictions on insider trading. Our evidence suggests that short sellers serve an important market disciplinary role by reducing insider trading profitability.     

从外部性控制策略分析主要环境经济手段的异同

随着世界经济的发展,环境污染问题日益严峻。环境污染是最典型的负外部行为。本文分析了西方经济理论中关于控制环境方面负外部性两种策略的分歧,对比了以这两种策略为理论渊源的排污收费制度和排污权交易制度的异同及各自的适用条件。     

中国股市波动性研究——基于Shiller-Sentana-Wadhwani模型

股票市场的价格波动并非像传统金融学所说得那样围绕公司基本价值进行小幅震荡，常常表现出大幅波动的特征。本文采用基于garch模型作出的Shiller-Sentana-Wadhwani模型对中国股票市场成立十多年的股价波动进行实证研究，得出中国股票市场存在反馈交易且其程度随着股价波动的增大而提高、随着涨跌限制而加大的结论。     

数字经济对我国碳排放的影响研究

基于2013-2020年的30个省份数据构建面板数据模型,从碳排放总量和碳排放强度两个视角研究数字经济发展对区域碳排放的影响。研究发现：数字经济的发展有效地降低了人均碳排放量、碳排放增量与碳排放增速,数字经济与碳排放强度之间存在倒“U”形关系,数字经济与碳排放强度、边际碳排放强度的关系呈现区域性特征,在省域层面数字经济对边际碳排放强度的影响不存在明显的空间效应,数字经济对碳排放增长率的影响存在基于产业结构优化、人口集聚、城镇化的遮掩效应。     

Carbon Trading with Imperfectly Observable Emissions

The Kyoto Protocol foresees emission trading but does not yet specify verification of (uncertain) emissions. This paper analyses a setting in which parties can meet their emission targets by reducing emissions, by investing in monitoring (reducing uncertainty of emissions) or by (bilaterally) trading permits. We derive the optimality conditions and carry out various numerical simulations. Our applications suggest that including uncertainty could increase compliance costs for the USA, Japan and the European Union. Central Europe and the Former Soviet Union might be able to gain from trading due to higher permit prices. Emissions trading could also lower aggregate uncertainty on emissions.     

Environmental Product Differentiation and Environmental Awareness

In this paper, we have considered a duopolistic model of environmental product differentiation with two types of consumers (green and brown) to analyze how environmental awareness affects the environment. “Green” consumers value the physical and environmental attributes of the good they purchase while “brown” consumers only value the physical attributes. We find that more environmental awareness may not be good news for the environment as the firm that produces the good without environmental attributes may increase its sales. The result depends on the degree of product differentiation and the cost to achieve it. Social welfare can also be inversely related to environmental awareness if the negative environmental effect dominates the positive market effect.      

Enforcing Emissions Trading when Emissions Permits are Bankable

We propose enforcement strategies for emissions trading programs with bankable emissions permits that guarantee complete compliance with minimal enforcement costs. Our strategies emphasize imperfect monitoring supported by a high unit penalty for reporting violations, and tying this penalty directly to equilibrium permit prices. This approach is quite different from several existing enforcement strategies that emphasize high unit penalties for emissions in excess of permit holdings. Our analysis suggests that a high penalty for excess emissions cannot be used to conserve monitoring effort, and that it may actually increase the amount of monitoring necessary to maintain compliance.The authors are grateful to Anthony Heyes and three anonymous referees for their valuable comments. Partial support for this research was provided by the Cooperative State Research Extension, Education Service, U. S. Department of Agriculture, Massachusetts Agricultural Experiment Station under Project No. MAS00871.     

运用排污权交易改善晋江市垃圾治理现状

如何建设节约型社会是时下舆论讨论的热点问题之一,正确处理好经济发展与环境保护也是建设和谐社会的核心命题之一。本文通过分析晋江市工业垃圾治理模式如何由靠牺牲环境为代价的粗放型模式—模式Ⅰ,向封闭的、可循环的集约型模式—模式Ⅱ转变,证明经济发展与环境保护是完全可以协调统一的;同时,通过分析模式Ⅱ的不足,进一步引入排污权交易理论,结合晋江市的实际情况,创造性地提出了具有实用性和通用性的垃圾治理方式——模式Ⅲ。     

Impacts of an EC carbon/energy tax and deregulating thermal power supply on CO2, SO2 and NOx emissions

Emission of CO₂, SO₂ and NO_x are all closely linked to the burning of fossil fuels. Here we report on simulations done by linking a Sectoral European Energy Model (SEEM), covering energy demand in nine Western European countries, with the emission-transport-deposition model RAINS developed by IIASA. The study analyses emissions of CO₂, SO₂ and NO_x, deposition of sulphur and nitrogen and the extent of areas where the critical load for sulphur is exceeded in year 2000 under four different energy scenarios. Two different sets of future behavioural patterns for the thermal electric power production sector are considered. In one regime, called the plan-efficient regime, the sector is assumed to follow official plans with regard to investment in new capacity. In the other regime, called the cost-efficient regime, the thermal power sector is assumed to behave in a cost minimizing manner. The effects of the proposed EC carbon/energy tax are studied under both regimes, giving rise to altogether four scenarios.In both regimes the effect of the EC tax is to reduce emissions by between 6 and 10 per cent in year 2000 relative to the scenarios without the tax. A change of regime, from the regulated, plan-efficient regime to the market-based, cost-efficient regime, will, by itself, reduce emissions of CO₂ and NO_x by approximately 3 per cent, while SO₂ emissions are reduced by 13 per cent. The EC tax will reduce sulphur deposition by more than 5 per cent in the nine model countries under the plan-efficient regime. A change of regime further reduces the total deposition by 9 per cent. The area where depositions exceed the critical load is reduced by approximately 6 per cent in year 2000 by the tax in both regimes. Changing from the plan-efficient to the cost-efficient regime has a similar impact.Although the emission reductions due to the EC tax may seem modest, they are shown to have a sizeable effect on the technological abatement costs of reaching targets like those prescribed in the Sofia protocol on the stabilisation of NO_x emissions, and the Helsinki protocol on SO₂ emission reductions. This is part of what can be considered to be secondary benefits of the EC carbon/energy tax.     

The Economics and Bioeconomics of Folk and Scientific Classification

Synopsis This paper is the product of a collaboration between a biologist (Ghiselin 1997) who works on the philosophy of classification and an economist (Landa 1981, 1994) who works on the ‘Economics of Identity’: how and why people classify people based on identity in the context of a theory of ethnic trading networks. In developing the ‘bioeconomics’ (the synthesis of economics with biology) of classification, we crossed a number of disciplinary boundaries—anthropology, economics, sociology, biology, and cognitive psychology including evolutionary psychology’s ‘fast and frugal’ heuristics. Using a bioeconomics approach, we argue that folk classifications—the classifications used by ordinary persons—have much in common with scientific classifications: underlying both is the need for economy of information processing in the brain, for the efficient organization of knowledge, and for efficiency of information acquisition and transmission of information to others. Both evolve as a result of trial and error, but in science there is relatively more foresight, understanding, and planning.