Optimality and consistency in a differential game with non-renewable resources

Imperfect competition amongst buyers for a non-renewable resource is modeled as a Stackelberg differential game. The buyers may act as a cartel or behave non-cooperatively in setting tariffs, which the sellers take as given. The buyer's optimal policy is not consistent when extraction costs depend on the stock level. Both optimal and consistent, unit and ad valorem tariff's are analyzed. When a buyers' cartel uses a consistent tariff, the sellers may prefer to behave as perfect competitors or a monopolist, depending on the functional form of demand and cost. Non-cooperative buyers who are constrained to act consistently are unable to extract any rent from competitive sellers.     

中国房地产交易真的是卖方市场吗？——基于双边随机边界模型的实证研究

科学测算房地产交易市场买卖双方议价能力对市场价格形成的影响作用，是当前政府制定“因地施策”宏观调控机制的重要前提。采用双边随机边界模型，考察房地产交易环节中买卖双方议价能力的差异,结果表明：（1）买卖双方讨价还价因素对商品房销售价格的最终形成存在显著影响；（2）从全国平均水平看，对于整体市场以及住宅、写字楼和商铺等细分市场，卖房者议价能力在双方讨价还价过程中占主导地位，但买方议价能力的影响作用也不容忽视；（3）从一线、新一线、二线和三线城市角度看，除了一线城市商铺市场以及三线城市总体城市、住宅市场和写字楼市场外，其他均处于卖方市场阶段。     

Group Buying Commitment and Sellers’ Competitive Advantages

This paper examines a model of duopoly firms selling to an exogenously formed buyer group consisting of members with heterogeneous preferences. Two research questions are addressed: (1) when is it optimal for a buyer group to commit to exclusive purchase from a single seller, and (2) how does the presence of group buying and the exclusive purchase commitment associated with it affect firms’ incentives to invest in quality improvement? We find that, even though exclusive purchase commitment benefits buyers when the competing products provide similar quality, it may lower buyer surplus if one product is significantly advantaged and/or the competing products are not highly differentiated horizontally. This result is robust even if the buyer group is formed endogenously. In addition, contingent on the similarity between the competing sellers’ investment costs, the sellers’ incentives to improve quality may be positively or negatively affected by the presence of group buying.     

二手房价格评估系统设计与研究

针对二手房交易过程中普遍存在的买卖双方信息不对称的问题,设计了一套基于B/S层次化结构的二手房价格评估系统。该系统首先通过网络爬虫从二手房网站收集公开的实时性数据信息,随后对这些数据进行预处理并建立层级化数据库。随后通过非参数回归算法对二手房价格进行评估。实验证明,本系统能够为购房者提供综合、直观的二手房趋势信息,并进行较为准确的估价。对于购房者以及售房者的决策都具有重要的参考价值。     

Countervailing power? Collusion in markets with decentralized trade

We consider the collective incentives of buyers and sellers to form cartels in markets with decentralized trade and pairwise bargaining. Cartels are coalitions of buyers or sellers that limit market participation and compensate inactive members for their abstention. In stable market outcomes, cartels set Nash equilibrium quantities and cartel memberships are immune to deviations. The set of stable market outcomes is non-empty and its full characterization is provided. Stable market outcomes are of two types: (i) at least one cartel restrains trade and market participation is balanced; (ii) only one cartel is active and it reduces trade slightly below the opponent’s.     

Information precision and asymptotic efficiency of industrial markets

I present a strategic model of a bilateral oligopoly with asymmetric information to examine (i) the validity of the conjecture of price-taking behavior in such markets as the number of agents becomes large and (ii) the effect of the rate that individual information precision decreases with increased number of agents on convergence to price-taking and efficiency. I show that with downstream competition, increasing the number of sellers may make all participants price-takers in the limit, but increasing the number of buyers may not. When the total precision of information in the market is high, price-taking and full social efficiency is achieved in the limit with large numbers of buyers and sellers. However, if the total precision of information in the market is poor, price-taking conjecture may fail and large inefficiencies, including full inefficiency, can occur in the limiting outcome. The rate of decrease of individual information precision with increased number of agents determines the rate of convergence to efficiency, and the convergence is slower than that predicted by single-unit auction models in the literature. I also demonstrate that when the number of sellers or both the number of buyers and the sellers go to infinity, price-taking and information aggregation tend to go together. When the number of buyers goes to infinity, however, information can get aggregated when the agents do not become price-takers in the limit. Albeit, in the latter case, the aggregated information is masked by the noise in the sellers’ signals and the cost variability.     

Can buyer “mobility” reduce aggregation failures in land-assembly?

In this paper we examine whether site-development competition can be used to facilitate land assembly, in the absence of contingent contracts. In particular, we attempt to determine (1) whether competition can be induced among prospective sellers, (2) whether or not competition increases aggregation rates, and (3) what effects competition has on the distribution of surplus among the bargaining parties. We also study the incidence with which a buyer (endogenously) chooses to deal with a single “large parcel” owner vs. multiple “small parcel” owners. To do so, we make use of a laboratory experiment where all the relevant information about the project is common knowledge and landowner valuations are private information. Our results show that competition more than doubles aggregation rates, with aggregation rates of approximately 40% in the baseline, and at least 84% in the competitive treatments. We also find that developers have a strong preference to make transactions with landowners who have consolidated land holdings, doing so in 24/27 successful aggregations, providing empirical evidence that there is a link between the transactions cost associated with land-assembly and suburbanization, as suggested by Miceli and Sirmans (2007).     

Reputation,Trust, and Rebates: How Online Auction Markets Can Improve Their Feedback Mechanisms

Reputation systems constitute an important institution, helping sustain trust in online auction markets. However, only half of buyers leave feedback after transactions, and nearly all feedback is positive. In this paper, I propose a mechanism whereby sellers can provide rebates (not necessarily in monetary form) to buyers contingent upon buyers' provision of reports. Using a game theoretical model, I show how the mechanism can increase unbiased reporting. There exists a pooling equilibrium where both good and bad sellers choose the rebate option, even though their true types are revealed through feedback. The mechanism also induces bad sellers to improve the quality of the contract.     

Buyers' Alliances for Bargaining Power

We provide a novel explanation as to why forming an alliance of buyers (or sellers) across separate markets can be advantageous when input prices are determined by bargaining. Our explanation helps to understand the prevalence of buyer cooperatives among small and medium-sized firms .     

Buyers' and sellers' cartels on markets with indivisible goods

This paper analyzes the formation of cartels of buyers and sellers in a simple model of trade inspired by Rubinstein and Wolinsky's (1990) bargaining model. When cartels are formed only on one side of the market, there is at most one stable cartel size. When cartels are formed sequentially on the two sides of the market, there is also at most one stable cartel configuration. Under bilateral collusion, buyers and sellers form cartels of equal sizes, and the cartels formed are smaller than under unilateral collusion. Both the buyers' and sellers' cartels choose to exclude only one trader from the market. This result suggests that there are limits to bilateral collusion, and that the threat of collusion on one side of the market does not lead to increased collusion on the other side.     

Non‐Neutral and Asymmetric Effects of Neutral Ratings: Evidence From eBay

Seller ratings help overcome adverse selection problems in online transactions between strangers. Using eBay data, we find that auction outcomes are sensitive toward not only positive and negative seller ratings but also neutral ratings. We find that (1) buyers utilize neutral ratings to sort among otherwise identical sellers and value their products and (2) contrary to eBay's opinion, depending on whether a seller is top‐notch or not, neutral ratings can be detrimental or beneficial; for sellers with higher proportions of positive ratings, an increase in neutral ratings decreases sales. For sellers with higher proportion of negative ratings, an increase in neutral ratings increases both sales and revenue. Copyright © 2014 John Wiley & Sons, Ltd.     

SEARCH AND VACANCY COSTS IN THE TOKYO HOUSING MARKET: ATTEMPT TO MEASURE SOCIAL COSTS OF IMPERFECT INFORMATION

The social cost of imperfect information, in terms of buyers' search costs and sellers' opportunity costs of vacancy, is estimated in the real estate market of resale condominiums in central Tokyo by using a new, comprehensive dataset of resale condominium transactions. The results suggest a substantial social cost. Specifically, if housing information were perfectly available and marketing time were null, sellers would get benefits of 22.59% of imputed net rents of their property. In addition, buyers would save 1,042,000 yen spent on search activities for one transaction, if information were perfect. This is equivalent to 13.2% of buyers' average annual income.     

Buyer–seller networks with demand shocks and intermediation

We present a model in which buyers and sellers use links to trade with each other. Each seller produces a good which can be one of two types. Buyers are ex ante identical but receive specification or valuation shocks after the links are formed. We show that efficient networks are stable and that severing a link in an efficient network results in a higher price for the buyer but a lower price for the seller. We also examine network intermediation when sellers (buyers) form links sequentially. When sellers form links sequentially, the first seller becomes an intermediary and shares links with other sellers; this makes all sellers better off. However, when buyers form links sequentially, buyers may or may not share links. If links are shared multiple intermediaries result.     

Horizontally Differentiated Market Makers

I analyze a model of competition between two market makers who are located at the opposite ends of the Hotelling line, both of which are also occupied by a search market. Buyers and sellers are uniformly distributed between the two market places, yet can only trade at one of them. In equilibrium, market makers net a positive profit and trade with buyers and sellers close to them, while buyers and sellers further away participate in search markets. Interestingly, a duopolistic market maker nets a larger profit than a monopoly because search markets make the quantities market makers trade strategic complements.     

Descending price multi-item auctions

We propose a simultaneous descending price auction mechanism to sell multiple heterogeneous items, each owned by a distinct seller, to a number of buyers. Each buyer has known private valuations on items, and wants at most one item. We show that if the sellers follow a descending price offer procedure and the buyers follow a greedy strategy for accepting the offers, the auction results in a nearly efficient allocation, and terminates close to a competitive equilibrium price vector. The descending price offer strategy of the sellers is close to a Nash equilibrium. However, we show that the buyers are better off waiting in our auction. There is a maximum limit (corresponding to the minimum competitive equilibrium price vector) till which they can wait without running into the risk of not winning any item. If the buyers wait within this limit, the prices can be brought arbitrarily close to a uniquely defined competitive equilibrium price vector.     

Adverse Selection with Competitive Inspection

We develop a model with heterogeneous buyers and sellers in which the sellers have private information about their goods' qualities. We show that efficient trading cannot occur without middlemen. Middlemen can provide two services: one is inspection, and the other is the sorting of buyers and sellers through the rationing of sellers and the provision of two different price schedules. The latter service permits the possibility of achieving the first best. When the first best is not attainable, there is a second best characterized by two intervals, one consisting of low-quality noninspected goods, and the other of high-quality inspected goods. We determine whether first and second best outcomes can be implemented in a market equilibrium with both zero and infinite buyer-seller search costs. First and second best outcomes are attainable under a larger set of parameter values when search costs are infinite; also, typically too much inspection occurs in a market equilibrium. Welfare may be either raised or lowered by the introduction of middlemen.     

Market Uncertainty and Socially Embedded Reputation

Both economists and sociologists generally recognize the importance of reputation in coordinating economic transactions. In a perfectly competitive and anonymous market characterized by faceless buyers and sellers, the issue of reputation would be irrelevant and unnecessary. In reality, however, markets are often filled with varying degrees of information asymmetry, which can threaten the very existence of the market system itself. In critical reaction to the standard neoclassical model, some economists, on the one hand, argue that when there is an information problem, reputation serves as a valuable source of market signal of quality. Sociologists of economic life similarly contend that reputation, along with trust, is critical in lowering transaction costs and thereby facilitating various economic activities among individual actors. The purpose of this article is to apply this broad theoretical observation to a specific empirical phenomenon. It does so by highlighting the role of social networks that connect actors on both demand and supply sides of the market. Specifically, this study examines how interpersonal networks in the market for legal services affect the duration of ties between buyers and sellers. Quantitative analysis based on a random sample of Chicago lawyers, a project funded by the American Bar Foundation, reveals that ceteris paribus the lawyer-client relations are significantly driven by social network factors.     

The effects of barriers to entry on monopolistic intermediary online services: The case of a digital library

Online intermediaries (OIs) are becoming increasingly important market institutions. They have low marginal costs and display the indirect network effect, which suggests that the benefit of an intermediary to sellers (buyers) increases with the number of buyers (sellers) connected to that intermediary. OIs may be further characterized by the levels of barriers to entry they face and the direct network effect, i.e., the benefit to a seller decreases with the number of sellers connected to the intermediary. This paper models a digital library where creators sell their works to information users. It is found that a monopolistic digital library with the above characteristics over-serves its creators, which leads them to over-invest in creation, and over-supply information products to consumers. Furthermore, the over-investment is more severe when the barriers to entry in the digital library sector are lower. A counter-intuitive policy implication is that removing barriers to entry in monopolistic markets with the above characteristics does not improve, but rather worsens, social welfare.     

The influence of seller learning and time constraints on sequential bargaining in an artificial perishable goods market

This paper investigates the formation of prices in a perishable goods market where agents bargain repeatedly through pair-wise interactions. After extensive field observations, we chose to focus on two aspects that seem important to actors of this market: the passage of time and update in judgement when gathering information. The main feature of the market is that a seller bargaining with a buyer has incomplete information about buyer's willingness to pay and is not sure how her trading partner will evaluate an offer or compare it with other options. On the other hand, buyers have limited time to look for goods and cannot meet all possible sellers before making a decision. Hence agents cannot calculate the best price to offer but receive information through limited interactions, and use this information to choose their actions.An agent-based model was built to represent a framework that mimics the observed market institution and where agent's possible behaviors and learning was made as consistent as possible with gathered data. Simulations were run, first for sensitivity analysis concerning main parameters, then to test the dependance of agents’ learning to (a) the time buyers can spend on the market and (b) the frequency of update in learning by sellers. To validate the model, features produced by the simulated market are compared to the stylized facts gathered for negotiation about four goods. We reproduce the main features of the data on the dynamics of offers, transaction prices and agents’ behavior during the bargaining phases.     

网商盘活第三方结算平台沉淀资金的对策研究

网络交易中各业务环节的时间延迟导致网商的销售款大量沉淀于第三方支付结算平台,由此导致网商面临营运资金吃紧、资金成本提高、财务规划困难和资金链脆弱等问题。买方、卖方、结算平台3方在沉淀资金盘活方面具有高度的可协调性,同时法律法规也提供了沉淀资金盘活的政策空间。网商可以通过签订循环融资协议直接盘活结算平台的沉淀资金,也可以通过对备货延迟、物流延迟和付款指令延迟的管理,实现对货款周转期的压缩,从而抑减沉淀在结算平台的资金规模。