Search costs and the severity of adverse selection

In view of some recent empirical evidence, I suggest a relationship between the magnitude of search costs and the severity of adverse selection in the context of a dynamic model with asymmetric information. In markets with small search costs sellers with low quality products misrepresent their quality and demand a high price. If search costs are not negligible, sellers׳ price offers are truthful and all product qualities are traded over time. In markets with small search costs, a budget balanced mechanism can mitigate adverse selection: sellers should pay a per period market participation tax and receive a rebate after trading.     

Inflation,price dispersion and market integration through the lens of a monetary search model

Monetary search theory implies that the real effects of inflation via its impact on price dispersion depend on the level of search costs and, thus, on the level of market integration. For less integrated markets, the inflation–price dispersion nexus is predicted to be asymmetrically V-shaped which results in an optimal inflation rate above zero. For highly integrated markets with low search costs, however, the impact of inflation on price dispersion should only be small. Using price data of the European Union member states, this paper tests and confirms these predictions of monetary search theory.     

声誉、搜寻成本与网上交易市场均衡

本文在搜寻理论的框架内分析了在卖家声誉存在差异的情况下,网上拍卖市场搜寻成本对价格水平和价格离差的影响,进而考察了搜寻成本对网上市场声誉机制的影响。本文的结论是:尽管搜索工具提高了网上交易市场的效率,但网上交易市场仍存在不可忽视的搜寻成本;较高的搜寻成本导致不同声誉水平的卖家同时存在于网上交易市场,高声誉卖家制定的价格较高,低声誉卖家制定的价格较低;搜寻效率的提高可以降低均衡价格水平,网站提供的推广服务也可以降低搜寻成本,降低均衡价格水平。模型很好地解释了网上拍卖市场中的一些现象,也与最近文献的经验事实有较好的吻合。     

The effects of information costs on search and convergence in experimental markets

Nearly all markets contain some kind of friction, making it difficult to reach full efficiency. One ubiquitous source of market friction is the cost of obtaining pricing information. We determine how market performance as well as buyer and seller behavior are affected by the introduction of price information costs in experimental posted markets.Rothschild [Journal of Political Economy (1973) 1283; Journal of Political Economy (1974) 689] theorizes that search is negatively related to knowledge of the price dispersion and the cost of search, and positively related to market price dispersion. We find that market knowledge and the cost of search itself affect search, but we find no evidence supporting the role of price dispersion in search decisions.We also find evidence supporting Smith and Plott [Review of Economic Studies (1979) 133] and Walker and Williams (1988), both of which show price convergence comes from below in posted-bid markets and from above in posted-offer markets. High information costs tend to reduce or eliminate convergence. Average prices are above the market-clearing price for posted-offer markets, and below for posted-bid markets, and never cross the market-clearing threshold, also consistent with Walker and Williams.More generally, our results support the notion of symmetry between experimental posted-offer and posted-bid markets, broadening the relevance of experimental search research.     

An experimental comparison of two search models

Summary. We report an experiment designed to investigate markets with consumer search costs. In markets where buyers are matched with one seller at a time, sellers are predicted to sell at prices equal to buyers' valuations. However, we find sellers post prices that offer a more equal division of the surplus, and these prices tend to be accepted, while prices closer to the equilibrium prediction are rejected. At the other extreme, sellers are predicted to sell at a price equal to marginal cost when buyers are matched with two sellers at a time. Here, we find prices are closer to, but still significantly different from, the equilibrium prediction. Thus, our results support theoretical comparative static, but not point, predictions.     

WHO SEARCHES?*

We consider a directed search model with buyers and sellers and determine whether buyers look for sellers or vice versa. The buyers and sellers can choose to search or wait; what they do in equilibrium depends on the relative size of the two populations and the price formation mechanism. We study bargaining and auctions and find that when one population is much larger than the other the former searches and the latter waits. Under auction with roughly equal populations some buyers and sellers search and some wait. Our results challenge the practice of postulating who searches and who waits.     

The (Q,S,s) pricing rule: a quantitative analysis

Are nominal prices sticky because menu costs prevent sellers from continuously adjusting their prices to keep up with inflation or because search frictions make sellers indifferent to any real price over some non-degenerate interval? The paper answers the question by developing and calibrating a model in which both search frictions and menu costs may generate price stickiness and sellers are subject to idiosyncratic shocks. The equilibrium of the calibrated model is such that sellers follow a (Q,S,s) pricing rule: each seller lets inflation erode the effective real value of the nominal prices until it reaches some point s and then pays the menu cost and sets a new nominal price with an effective real value drawn from a distribution with support [S, Q], with s < S < Q. Idiosyncratic shocks short-circuit the repricing cycle and may lead to negative price changes. The calibrated model reproduces closely the properties of the empirical price and price-change distributions. The calibrated model implies that search frictions are the main source of nominal price stickiness.     

Information externalities and intermediaries in frictional search markets

In frictional matching markets with heterogeneous buyers and sellers, sellers incur discrete showing costs to show goods to buyers who incur discrete inspection costs to assess the suitability of the goods on offer. We study how brokers can help reduce these costs by managing the level and mix of goods in their inventory. Intermediaries emerge and improve social welfare when there is sufficient heterogeneity in the types of goods and preferences. Learning and inventory management enable search intermediaries to internalize information externalities generated in unintermediated private search.     

Dissertation abstract: Essays on pricing in experimental duopoly markets

This dissertation comprises three independent essays that analyze pricing behavior in experimental duopoly markets. The first essay examines whether the content of buyer information and the timing of its dissemination affects seller market power. We construct laboratory markets with differentiated goods and costly buyer search in which sellers simultaneously post prices. The experiment varies the information on price or product characteristics that buyers learn under different timing assumptions (pre- and post-search), generating four information treatments. Theory predicts that price information lowers the equilibrium price, but information about product characteristics increases the equilibrium price. That is, contrary to simple intuition, presence of informed buyers may impart a negative externality on other uninformed buyers. The data support the model's negative externality result when sellers face a large number of robot buyers that are programmed to search optimally. Observed prices conform to the model's comparative statics and are broadly consistent with predicted levels. With human buyers, however, excessive search instigates increased price competition and sellers post prices that are significantly lower than predicted. The second essay uses experimental methods to demonstrate the anti-competitive potential of price-matching guarantees in both symmetric and asymmetric cost duopolies. When costs are symmetric, price-matching guarantees increase the posted prices to the collusive level. With asymmetric costs, guaranteed prices remain high relative to prices without the use of guarantees, but the overall ability of guarantees to act as a collusion facilitating device depends on the relative cost difference. Fewer guarantees, combined with lower average prices, suggest that cost asymmetries may discourage collusion. The third essay investigates the effect of firm size asymmetry on the emergence of price leadership in a homogeneous good duopoly. With discounting, the unique subgame-perfect equilibrium predicts that the large firm will emerge as the endogenous price leader. Independent of the level of size asymmetry, the laboratory data indicates that price leadership by the large firm is one of the most frequently observed timings of price announcement. In most cases, however, it comes second to simultaneous price-setting. This tendency to wait for the other firm to announce its price is especially strong when the level of size asymmetry between firms is low. We attribute the lower than expected frequency of price leadership to coordination failure, which is further compounded by elements of inequity aversion. JEL Classification C91, D43, D83, L11 Dissertation Committee: Timothy Cason (Chair), Department of Economics, Purdue University Dan Kovenock, Department of Economics, Purdue University Stephen Martin, Department of Economics, Purdue University Marco Casari, Department of Economics, Purdue University     

High profit equilibria in directed search models

We consider a model of directed search where the sellers are allowed to post mechanisms with entry fees. Regardless of the number of buyers and sellers, the sellers are able to extract all the surplus of the buyers by introducing entry fees and making price schedules positively sloped in the number of buyers arriving to their shops. This is in contrast to results that are achieved for large markets under the assumption that sellers cannot influence the utility of any particular buyer (market utility assumption), in which case buyers obtain strictly positive rents. If there is a bound on the prices or on the entry fees that can be charged, then the equilibrium with full rent extraction does not exist any more, and the market utility assumption is restored for large markets.     

THE HIDDEN COST OF BARGAINING: EVIDENCE FROM A CHEATING-PRONE MARKETPLACE

It is widely believed that successful bargaining helps consumers increase their surplus. We present evidence from a field experiment showing that bargaining over price reduces buyer surplus in a marketplace where sellers cheat on the weight whose value may more than offset the price discount. Our results show that bargaining entails hidden costs since sellers cheat significantly more when buyers bargain than not and they cheat significantly more when bargaining succeeds than fails. Overall bargaining reduces buyer surplus than not bargaining. Our result is relevant for credence goods markets where bargaining over prices may induce sellers to “undertreat” more.     

The Stability of Price Dispersion under Seller and Consumer Learning*

In many markets, it is possible to find rival sellers charging different prices for the same good. Earlier research has attempted to explain this phenomenon by demonstrating the existence of dispersed price equilibria when consumers must make use of costly search to discover prices. We ask whether such equilibria can be learned when sellers adjust prices adaptively in response to current market conditions. With consumer behavior fixed, convergence to a dispersed price equilibrium is possible in some cases. However, once consumer learning is introduced, the monopoly outcome first found by Diamond (Journal of Economic Theory3 (1971), 156–68) is the only stable equilibrium.     

Money and Price Dispersion

We relax restrictions on the storage technology in a prototypical monetary search model to study price dispersion. In this case, buyers and sellers enter matches with potentially different willingness to trade. Across the distribution of possible bilateral matches, prices generally will differ even though agents have identical preferences and technologies. We provide existence conditions for a particularly simple equilibrium pattern of exchange. We prove that in the limiting case where search frictions are eliminated, equilibrium prices are uniform. We also show that a higher initial money stock can raise the average price level and increase price dispersion.     

Income distribution and exchange in a dynamic search model

This paper studies the link between income distribution and trade mechanisms in a dynamic search model with two-sided asymmetric information. Buyers and sellers have imperfect information about the income levels of the other group. Furthermore, asymmetry of information about incomes is the source of price dispersion. In such a frictional environment, we capture the effects of a change in inter- and intra-class income distribution on the trade mechanism, which is represented by the expected trade volume and the flux of buyers and sellers in the market.     

INFLATION AND THE DISPERSION OF REAL WAGES*

The article studies the effects of inflation on real wage dispersion in a search‐monetary framework. The economy is characterized by frictions in both the goods and the labor markets. In the goods market, buyers and sellers bargain over prices, whereas in the labor market firms post wage offers. In equilibrium, a lower inflation rate increases the dispersion of real wages. This result is consistent with both the observed trends in wage dispersion and the inflation rate witnessed in the 1980s and the 1990s in the United States and the empirical literature linking reduced inflation to greater wage dispersion.     

COMPETITIVE PRICING AND EFFICIENCY IN SEARCH EQUILIBRIUM*

We consolidate and generalize some results on price determination and efficiency in search equilibrium. Extending models by Rubinstein and Wolinsky and by Gale, heterogeneous buyers and sellers meet according to a general matching technology and prices are determined by a general bargaining condition. When the discount rate r and search costs converge to 0, we show that prices in all exchanges are the same and equal the competitive, market clearing, price. Given positive search costs, efficiency obtains iff bargaining satisfies Hosios' condition and r=0. When prices are set by third‐party market makers, however, we show that search equilibrium is necessarily efficient.     

金融资产定价异常现象研究综述及其对新资产定价理论的启示

论文首先通过建立模型分析了在不同知情消费者比例下价格离散的结构形式,理论剖析了在搜索成本明显下降的电子商务市场,价格离散仍然持续存在的客观原因;进而运用在北京地区的93家电子商务零售网站、9大类535款商品、6313个价格样本数据检验了中国电子商务市场价格离散的情况,研究了其价格离散成因。结果表明在电子商务市场上,价格离散将持续存在,知情消费者比例与价格离散指标之间并不是一个单调关系;零售商特征,尤其是市场特征影响价格离散,各类零售商的定价依据不同。     

AN EQUILIBRIUM SEARCH MODEL OF SYNCHRONIZED SALES*

We demonstrate the existence of periodic nonstationary equilibria with self‐generating cycles in a simple model of random search. Our results provide a theory of synchronized sales based on product market search by heterogeneous consumers. That is, our model explains how it can be optimal for all sellers to follow a repeated pattern of posting a high price for several periods and then posting a low price for one period.     

The cost of search and rational random behavior

Sequential search for the lowest price is shown to be directly related to Theil's (1979) rational random behavior approach. An explicit relationship between the optimal number of searches and the optimal decision distribution is derived for the exponential family of price distributions.