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.     

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.     

The holdout problem and urban sprawl: Experimental evidence

Conventional wisdom as well as economic theory suggests it is more costly to reassemble fragmented land due to transactions costs and strategic bargaining costs. Both costs are expected to increase with the number of sellers. Inefficient allocation of land resources may result including property entropy (Parisi, 2002), urban sprawl (Miceli and Sirmans, 2007) and deteriorating inner cities. Given the difficulty of observing actual values attached by buyers and sellers to land, little empirical evidence exists to support the conventional wisdom and theoretical work. We use experimental methods to examine transactions costs and strategic bargaining costs in a land-assembly market game with one buyer, 1-4 sellers, and complementary exchanges. The buyer’s final earnings vary inversely with the number of sellers, ceteris paribus, indicating an incentive to purchase consolidated land. Delay costs reduce holdout, but result in lower payoffs for both buyers and sellers. Competition between sellers reduces holdout and the buyer’s total purchase price.     

The Role of Coordination Bias in Platform Competition

This paper considers platform competition in a two‐sided market that includes buyers and sellers. One of the platforms benefits from a favorable coordination bias in the market, in that for this platform it is less costly than for the other platform to convince customers that the two sides will coordinate on joining it. We find that the degree of the coordination bias affects the platform's decision regarding the business model (i.e., whether to subsidize buyers or sellers), the access fees, and the size of the platform. A slight increase in the coordination bias may induce the advantaged platform to switch from subsidizing sellers to subsidizing buyers, or induce the disadvantaged platform to switch from subsidizing buyers to subsidizing sellers. Moreover, in such a case the advantaged platform switches from oversupplying to undersupplying sellers, and the disadvantaged platform switches from undersupplying to oversupplying sellers.     

Intermediated surge pricing

Although Uber and Lyft are known for their flexible “surge pricing,” they are surprisingly rigid in another way: each firm takes a constant percentage of passenger fare whether or not there is a surge. In this paper, I investigate the possible reasons for, and the impact of, this rigidity. I study a market in which a profit‐maximizing intermediary facilitates trade between buyers and sellers. The intermediary sets prices for buyers and sellers, and keeps the difference as her fee. Optimal prices increase when demand increases, that is, shifts right. If a demand increase is due to an increase in the number of ex ante symmetric buyers, then the intermediary's optimal percent fee decreases. If, instead, a demand increase is due to a reduction in the elasticity of demand, then the intermediary's optimal percent fee increases. In either case, if the intermediary keeps a constant percent fee regardless of shifts in demand, as is the case with Uber and Lyft, then surge pricing (i.e., the ratio of price during high demand to price during low demand) is amplified on one side of the market and diminished on the other side.     

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.     

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.     

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。     

Buyer information and the hedonic: The impact of a seller disclosure on the implicit price for airport noise

Revealed preference methods like the hedonic model generally assume economic agents have access to publicly available information and use it effectively. In the housing market, the recent proliferation of seller disclosure laws suggests that policymakers perceive buyers to be less than “fully informed,” presumably since they face higher information acquisition costs than sellers. The introduction of an airport noise disclosure in the residential housing market surrounding the Raleigh–Durham International Airport is used as a quasi-random experiment to analyze the impact of this type of information asymmetry between buyers and sellers on housing prices. The results from a regression analysis that controls for potential spatial and temporal confounders, suggest that the airport noise disclosure reduced the value of houses most heavily impacted by airport noise by 2.9 percent. This represents approximately a 37 percentage point increase in the implicit price of airport noise. The results provide evidence that publicly available information, such as that available for airport noise, may not be adequately considered by all buyers. They also suggest that the information environment should be carefully considered when using housing data and the hedonic model to value urban amenities and disamenities.     

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.     

Management consultants as improvising agents of stability

Relatively few studies have paid theoretical as well as empirical attention to what use organizations have of management consultants and their services. By studying how buyers and sellers of management consulting services describe what management consulting is and represents, this study questions common understandings in the literature, i.e., that management consultants act as agents of change or as standardizers of organizational practice around the world. It is argued that consultants can be understood as playing the role of improvisers because there is considerable uncertainty among both buyers and sellers as to what use organizations really have of them. Playing a recognizable, yet indefinite role based on an institutionalized foundation, in both discourse and practice, of what actors such as consultants are supposed to do in certain situations, helps client organizations to reduce the uncertainty experienced. The conclusion is that management consultants can therefore be understood as agents of stability rather than agents of change.     

Ordering sellers in sequential auctions

We examine how buyers’ behaviors, sellers’ profits and the social welfare (the total surplus of all sellers and buyers) vary with the order of sellers in sequential auctions where sellers have different reservation values. First, when reserve prices are exogenously set to be sellers’ reservation values, a social planner would order sellers from low to high based on their reservation values, which yields a uniquely efficient order that maximizes the social welfare. However, an auctioneer charged with maximizing the total profit of all sellers would want to reverse the increasing order in certain situations. Second, when reserve prices can be endogenously selected in addition to the order of sellers, the auctioneer would always want to adopt the increasing order for the optimally chosen reserve prices. Sequential auctions with optimally chosen reserve prices and an increasing order are shown optimal among the class of voluntary and incentive-compatible mechanisms.     

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.     

On axiomatizations of the Shapley value for assignment games

We consider the problem of axiomatizing the Shapley value on the class of assignment games. It turns out that several axiomatizations of the Shapley value on the class of all TU-games do not characterize this solution on the class of assignment games. However, when considering an assignment game as a (communication) graph game where the game is simply the assignment game and the graph is a corresponding bipartite graph where buyers (sellers) are connected with sellers (buyers) only, we show that Myerson’s component efficiency and fairness axioms do characterize the Shapley value on the class of assignment games. Moreover, these two axioms have a natural interpretation for assignment games. Component efficiency yields submarket efficiency stating that the sum of the payoffs of all players in a submarket equals the worth of that submarket, where a submarket is a set of buyers and sellers such that all buyers in this set have zero valuation for the goods offered by the sellers outside the set, and all buyers outside the set have zero valuations for the goods offered by sellers inside the set. Fairness of the graph game solution boils down to valuation fairness stating that only changing the valuation of one particular buyer for the good offered by a particular seller changes the payoffs of this buyer and seller by the same amount.     

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.     

Divergence in Reservation Prices and Its Impact on Housing Market Liquidity: A Theoretical Analysis

In this paper, we build a two-period English auction model to study the relative movements between buyers’ and sellers’ reservation prices in the housing market. We show that changes in sellers’ reservation prices are jointly determined by changes in buyers’ reservation prices, probability of buyers offering a high or low price, and the arrival rate of buyers. When the divergence between the buyers’ and sellers’ reservation prices widens, the probability of sale increases in the upward market and decreases in the downward market, contributing to the increases or decreases in market liquidity.     

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.     

Core and competitive equilibria: An approach from discrete convex analysis

We extend the assignment market (Shapley and Shubik, 1972; Kaneko, 1976, 1982) by utilizing discrete convex analysis. We consider the market in which buyers and sellers trade indivisible commodities for money. Each buyer demands at most one unit of commodity. Each seller produces multiple units of several types of commodities. We make the quasi-linearity assumption on the sellers, but not on the buyers. We assume that the cost function of each seller is M^♮-convex, which is a concept in discrete convex analysis. We prove that the core and the competitive equilibria exist and coincide in our market model.     

List price and sales prices of residential properties during booms and busts

This paper investigates the relationship between the list and sale price of residential properties over the housing cycle. In down or normal markets the list price generally exceeds the sales price; however, when the housing market is strong, homes sell for more than their list price. This observation is not consistent with the assumptions made in the standard model of home sellers’ search behavior. We consider alternative models. In one, sellers set list prices based on their expectations of future changes in sales prices and the arrival rate of buyers; however, demand shocks occur. This model partially explains our data from the Belfast, U.K. housing market, but it fails to predict the list to sales price ratio during a sustained housing boom. We next describe a model where sellers’ endogenously select their search mechanism depending on the strength of the housing market. We find support for the conjecture that sellers switch to an auction-like model during housing booms. There also is evidence that during a downturn in the market, sellers’ list prices are sticky.     

On second-price auctions and imperfect competition

Consider two sellers each of whom has one unit of an indivisible good and two buyers each of whom is interested in buying one unit. The sellers simultaneously set reserve prices and use second-price auctions as rationing device. An equilibrium in pure strategies where each seller has a regular customer is characterized. The result is applied in order to demonstrate that not allowing sellers to use second-price auctions may enhance total surplus.