次优理论探析及其应用

在现实经济中一个能达到帕累托最优的完全竞争市场是不可能的。福利经济学的次优理论承认垄断是一种扭曲的市场环境，它认为在扭曲因素影响下的最大值解是低于帕累托最优值解的次优解。当经济环境中存在外部性、垄断、商品税等扭曲因素约束时，承认这些约束因素，然后再寻找最优的资源配置组合。我国经济转轨中选择的转轨方式，实际是一个次优的选择。我国的渐进式改革其实质也是一种典型的次优。     

竞争市场与垄断市场:一个基于福利的分析

传统经济理论认为垄断会导致社会福利的损失。在它的分析框架中。实际上瞻舍着成本不变假说，即完全竞争市场中的企业与垄断市场中的企业的成本(或边际成本)是相同的。规模经济理论告诉我们，规模大的企业更容易形成规模经济效果，因而垄断企业的规模经济效果是完全竞争企业不可比拟的，成本不变假说就显得很不真实。本文试图证明在某种前提(如资金密集型产业和知识密集型产业)下垄断所带来的规模经济效果能够弥补社会福利的损失，甚至使社会总福利增加。这一结论对我国市场化改革具有现实意义。     

论重构我国的市场结构

一、有效竞争理论 竞争机制是市场实现对资源优化配置的重要杠杆,它通过优胜劣汰的过程,使资源不断由劣势企业和行业向优势企业和行业转移,极大地促进了社会经济活动效率的提高.然而,竞争机制在发挥作用的同时,也内生出自身的对立面.自由竞争势必会引起生产集中,生产集中发展到一定程度就会引起垄断.在现实生活中,垄断与竞争往往是并存的.根据市场上竞争和垄断程度不同,可以把市场划分为四种结构:完全竞争市场、垄断竞争市场、寡头垄断市场和完全垄断市场.     

保险发展、市场结构对社会福利的影响研究

本文在一个封闭的拉姆齐模型的基础上,引入代表性行为人具有有限生命的条件,探讨保险发展、市场结构改变对社会福利的影响.发现保险发展在一定条件下可增进社会福利,保险市场垄断降低竞争加强会提高福利.然后,本文利用中国31个省市在2005-2014 年间的面板数据,考虑内生性,采用2SLS方法,进一步将保险发展划分为为保险深度与保险赔付两个层次,对保险发展与保险市场结构影响福利的规律进行了计量分析.研究发现保险深度、保险赔付均可显著提高福利水平,同时保险市场垄断程度的降低会显著提高福利水平.基于面板门槛回归表明,保险深度、赔付与市场结构对社会福利的影响存在较为明显的门槛效应.     

垄断竞争市场中的创新竞争力 ——基于伊利集团的案例分析

市场理论中包括四种市场组织,分别为完全竞争市场、垄断市场、垄断竞争市场和寡头垄断市场.其中垄断竞争市场在我们生活中普遍存在,垄断竞争市场的垄断和竞争分别来源于产品的差异化和产品的替代性.垄断竞争市场中的创新战略包括产品战略、市场战略、价格战略、广告战略、顾客战略以及文化战略.通过分析伊利集团的创新战略,研究创新对企业竞争力的影响.     

上游产品市场中的环境税机制研究——基于完全信息静态博弈视角

本文通过构建纵向关联市场结构下博弈模型,探讨下游市场特性如何影响上游污染企业环境税的制定.研究结果表明,下游市场最终产品差异性与上游企业环境税的征收起点呈正相关关系.进一步研究发现,当下游企业同时进入市场时,上游企业最优环境税低于“庇古税”.而当下游企业依次进入最终产品市场时,最优环境税与“庇古税”的关系则取决于污染排放造成的边际社会损失.当污染对社会福利损害比较小(大)时,最优环境税低(高)于“庇古税”.     

互联网经济:资源配置新模式

在西方经济学经典理论中,我们学习过市场论,包括完全竞争市场和不完全竞争的市场,而不完全竞争的市场又包括垄断市场、寡头市场和垄断竞争市场。完全竞争市场要具备四个条件:1.市场上有大量的买者和卖者;2.市场上每一个厂商提供的商品都是完全同质的;3.所有的资源具有完全的流动性;4.信息是完全的。在现实生活中,这四个条件很难满足,所以我们往往接触到的是不完全竞争的市场。如:我们每天用的自来水,在西方经济学理论中被认为是典型的垄断市场,而且是自然垄断。还有寡头市场,也是我国市场经济的重要形式。如:成品油市场由中国石油、中国石化、中国海油三家企业垄断;通讯市场由中国移动、中国联通、中国电信三家企业占有;供电市场由国家电网和南方电网两家企业负责。在日常用品零售领域中,垄断竞争市场一般充当主要的经济形式。如:服装、食品等生活用品领域,一般都会有几家到十几家企业生产同类相似产品。绝对的完全竞争市场是不存在的,现实生活中的市场要么是竞争性多一点,要么是垄断性多一点。西方经济学家们通过数理模型,推导出完全竞争市场是比较有效率的,是能够给人们带来更大福利的,可是,经济学家们没有办法建立一个完全竞争市场。而当今,互联网经济的发展将经济学家们的这一想法推进了一步。     

环境偏好和环境税视角下企业技术决策博弈分析

构建双寡头垄断市场下企业技术决策的博弈模型,并将消费者环境偏好和环境税引入模型。首先分析消费者的环境偏好对市场需求的影响;然后运用逆向归纳法探讨企业在环境税约束下的两阶段博弈;最后分析消费者环境偏好和环境税对企业技术决策的综合影响。研究表明:消费者的环境偏好降低了双寡头垄断企业的市场需求,激发了企业在没有环境税下采纳绿色技术的动机;当征收环境税时,企业采纳绿色技术的效益与环境税率的关系曲线呈倒U型,消费者的环境偏好与环境税引发的效益区间正比变动。     

消费者沉淀投资、垄断与政府管制目标

如果企业处于完全竞争行业中,市场供求价格机制会实现帕累托最优,无需任何中介组织和政府管制;如果企业处于自然或人为垄断的市场条件下,政府管制就十分必要,此时往往将管制目标确定为社会福利最大化.当消费者购买产品进行沉淀成本投资,消费者无法自由进入和自由退出,垄断企业就与消费者产生了双边谈判,进而会引起敲竹杠行为,大大降低消费者剩余,即便实现了社会福利最大化也会带来收入不公平问题.在这种情况下,政府管制目标就需要由社会福利最大化转向消费者剩余最大化,否则,不仅不会实现管制目标,而且还会恶化消费者剩余,从而使消费者合理合法地处于不公平的地位.因而,针对垄断市场,尤其是自然垄断(主要是公用事业部门)市场所进行改革以及重新认识消费者—企业—政府之间的关系,对于完善中国特色的社会主义市场经济体制具有重要意义.     

价格歧视战略与福利效应分析

在完全竞争市场条件下 ,竞争均衡可实现帕累托最优效率。垄断市场一般很难提供价格等于边际成本的产量水平 ,其产量与价格选择对社会来说不是最优的。垄断厂商以内生范畴和外生范畴为基础对消费者进行分类 ,使得价格歧视成为一种可行战略。由于定价策略存在差异 ,不同类型的价格歧视便具有不同的福利效应。     

Trade Liberalization and Environmental Regulation on International Transportation

Incorporating pollution emissions from international transportation into a model of strategic trade and environmental policies, we investigate the effect of trade liberalization and environmental regulation on national welfare and the environment. Our model includes imperfectly competitive markets for international transportation and final products. We find that trade liberalization may reduce each country's welfare unless some level of environmental regulation on international transportation is in place. When international trade is liberalized initially, a mutual increase in the common emission tax rates may improve each country's welfare. However, when international trade is highly protected initially, imposing an emission tax may reduce welfare.     

Green certification,heterogeneous producers,and green consumers: a welfare analysis of environmental regulations

We develop a vertical differentiation model to analyze welfare implications of environmental policies in a competitive market with production and consumption heterogeneity. Consumers with heterogeneous preferences choose between non-green and certified green products, while producers with heterogeneous production costs decide whether to engage in green production. In order for green products to be recognized by consumers, producers must join a green club. Key findings are summarized as follows. (i) The number of green producers, environmental standard, and overall welfare under the market solution are all socially sub-optimal. (ii) The introduction of a subsidy policy for greener production and standards is shown to increase social welfare, but is not Pareto optimal. (iii) A dual policy, which combines abatement subsidizes for a greener production standard and a tax charge for green certification, is shown to be the Pareto-optimal outcome.     

Dynamic analysis of bribery firms’ environmental tax evasion in an emissions trading market

Using an R&D-based growth model with dual regulation, we analyse how environmental policies influence pollution, corruption, a growth rate, and welfare. Considering that polluting firms bribe bureaucrats to evade paying environmental tax, we find that a stricter environmental tax leads to a decrease in growth rate via a decrease in the permit rent as well as an increase in pollution and corruption per firm and results in worsening households’ welfare and in improving the bureaucrats’ welfare. Thus, tax evasion with corruption improves households’ welfare and worsens the bureaucrats’ welfare. Our findings imply that tax evasion under dual regulation improves social welfare.     

A search model of centralized and decentralized trade

This paper presents a search model of centralized and decentralized trade. In a centralized market, trades are intermediated by market makers at publicly posted bid–ask prices. In a decentralized market, traders search counterparties. Prices are negotiated and transactions are conducted in private meetings among traders. Traders can choose which market to enter. The determinants of bid–ask spreads and liquidity are analyzed. The welfare consequence of the market fragmentation is also analyzed. It is shown that compared to the competitive market-making, monopolistic market-making may improve social welfare.     

基于节能减排技术研发的企业联盟合作模式选择

在征收外生排放税的条件下,利用两阶段动态博弈模型探讨了开展节能减排技术研发的企业对3种联盟合作模式的选择。通过全面比较不联盟合作模式、半联盟合作模式和全联盟合作模式下的均衡产量、生产工艺研发水平、污染减排研发水平、利润和社会福利,得出全联盟合作模式是企业最佳选择的结论。     

Do exclusivity arrangements harm consumers?

This paper explores the ramifications of exclusivity arrangements, e.g., iPhone’s partnership with wireless carriers, for market competition and consumer welfare. Two firms compete in a primary good market, and a monopolistic firm offers a value-adding good. The primary good can be consumed alone, while the value-adding good must be consumed with the primary good. The monopolistic firm forms an exclusivity partnership with one of the primary good providers. Buyers are able to consume the value-adding good only if they patronize the monopolistic firm’s exclusive partner. This practice allows the monopolistic firm to extract surplus from the primary good market. Surprisingly, consumers benefit from the exclusivity arrangement. However, overall social welfare declines, despite improvements to consumer welfare.     

Environmental taxes and industry monopolization

This paper considers a market with an incumbent monopolistic firm and a potential entrant. Production by both firms causes polluting emissions. The government selects a tax per unit of emission to maximize social welfare. The size of the tax rate affects whether or not the potential entrant enters the market. We identify the conditions that create a market structure where the preferences of the government and the incumbent firm coincide. Interestingly, there are cases where both the government and incumbent firm prefer a monopoly. Hence, the government might induce profitable monopolization by using a socially optimal tax policy instrument.      

双边市场、不完全信息与二级价格歧视

本文研究了双边市场二级价格歧视问题。本文构建了包括广告商、消费者、垄断平台在内的两阶段博弈模型，研究了在最优与次优情况下平台的定价机制，分析了二级价格歧视对平台利润、社会福利等的影响。研究表明：（1）“顶部无扭曲”或“底部无扭曲”并不严格成立；（2）平台对观众提供的节目质量、广告插播量均可能出现类型逆转的情况；（3）二级价格歧视会增加社会总福利；（4）“会员制”是平台可能的占优定价机制之一。     

Unemployment equilibrium and economic policy in mixed markets

This paper features a simple static Cournot-Nash model of an exchange economy with two productive sectors at flexible prices and wages. The traders in the atomless sector are price-takers, while the atoms behave strategically. We focus on the consequences of strategic interactions on the market outcome. Firstly, strategic interactions create underemployment on the labor market. Secondly, when the number of atoms increases without limit, the CWE coincides with the competitive equilibrium. Thirdly, we compare the welfare reached by traders at both equilibria. Fourthly, we consider the implementation of a tax levied on strategic supplies. Finally, we compare the approach retained with the monopolistic competition framework.     

Bidding in an Electricity Pay-as-Bid Auction

One of the main elements of the recent reform of electricity trading in the United Kingdom is the change from a uniform price auction in the wholesale market to discriminatory pricing. We analyze this change under two polar market structures (perfectly competitive and monopolistic supply), with demand uncertainty. We find that under perfect competition there is a trade-off between efficiency and consumer surplus between the two auction rules. We also establish that a move from uniform to discriminatory pricing under monopoly conditions has a negative impact on profits and output (weakly), a positive impact on consumer surplus, and ambiguous implications for welfare and average prices.