Estimating Bargaining Effects in Hedonic Models: Evidence from the Housing Market

Bargaining is common in markets for heterogeneous goods and differences in bargaining power between buyer and seller affect the negotiated transaction price. Previous research has found systematic evidence in the housing markets that weak buyers pay higher prices and weak sellers receive lower prices for their homes. Earlier work has modeled the bargaining effect as a parallel shift in the hedonic function, implicitly assuming that attribute shadow prices were unaffected by the bargaining process. In this paper, we use a sample of home sales where the seller's bargaining power is weakened by the fact that the home is vacant at the time of sale to test whether the effect of bargaining is best captured by a shift in the hedonic constant or whether the attribute shadow prices vary as well. The question is significant for property valuation where estimation of the marginal value of an attribute is commonly used to adjust comparable sales data. We find strong confirmation that bargaining power influences the negotiated price. We also find evidence that bargaining power alters attribute prices, although we do not find a consistent pattern across markets.     

Price dispersion and seller heterogeneity in retail food markets

Price dispersion, i.e. a homogeneous product being sold at different prices by different sellers, is among the most replicated findings in empirical economics. The paper assesses the extent and determinants of spatial price dispersion for 14 perfectly homogeneous food products in more than 400 retailers in a market characterized by the persistence of a large number of relatively small traditional food stores, alongside large supermarkets. The extent of observed price dispersion is quite high. When prices in an urban area (where the spatial concentration of sellers is higher) are compared with those in smaller towns and rural areas, differences in search costs and the potentially higher degree of competition do not yield lower prices. Other counteracting factors, including differences in seller costs and consumer incomes, make prices, on average, higher in the urban area for 11 of the 14 products considered. For many, but not all, the products supermarkets proved to be less expensive than traditional retailers, although average savings from food shopping at supermarkets were extremely low. Finally, the results of the study provide evidence that retailers have different pricing strategies and these differences also emerge for supermarkets belonging to the same chain. The results presented in the paper suggest that a variety of factors play a role in explaining price dispersion. In addition to differences in seller costs, the contemporaneous heterogeneity of retailers (in terms of services provided) and consumers (in terms of search costs and preferences) makes the emergence of monopolistic competition possible as well as allowing small traditional food retailers to remain in business.     

An Experimental Analysis of the Impact of Intermediaries on the Outcome of Bargaining Games

We conduct an experimental analysis of the bargaining between a buyer and a seller of the exchange of a single good by means of an intermediary or broker. We examine how an intermediary affects the price, the likelihood of a successful negotiation, and the time it takes to complete a negotiation. We first examine the impact of the intermediary as a pure middleman, and then as an information source about the distribution of seller and buyer reservation prices. The results show that an intermediary, whether or not informed, increases the sale price, reduces the likelihood of an agreement, and increases the time to reach an agreement (though the number of bargaining rounds declines). The results suggest that the benefits of brokerage may be predominantly in the matching of buyers and sellers rather than in facilitating bargaining.     

Search and price dispersion in online grocery markets

Consumers often purchase multiple products at a time from retailers, creating multi-product incentives for search. In this paper we consider how product variety affects consumer search intensity and the dispersion of prices in multi-product retail markets. We employ online grocery pricing data from four large retailers in the UK to estimate search costs and equilibrium price dispersion for food products under circumstances where: (i) consumers search for single products; and (ii) consumers search for multiple products at once. We compare estimates in each case between a model in which utility increases with product variety and a model in which utility is not a function of variety. Relative to our preferred specification with variety effects in utility, we find estimates of both search cost and search frequency to be biased upwards in single product settings when variety effects are ignored; however, we find estimates of search costs are biased upwards while search frequency is biased downwards in multi-product settings when variety effects in utility are ignored.     

Buyer power through the differentiation of suppliers

This paper argues that rival retailers may choose to differentiate their supplying producers, even at the expense of downgrading the quality of the product offered to consumers, to improve their buyer power. We show that, through the differentiation of suppliers, a retailer may obtain a larger slice of a smaller pie, i.e, smaller bilateral joint profits. Thus, the “only” purpose of differentiation is to gain increasing buyer power. This result may hold (i) when retailers compete in the final market or (ii) when retailers are active in separate markets. The differentiation of suppliers, which results from a buyer power motive, may be harmful for consumer surplus and social welfare.     

Purchasing alliances and product variety

We analyze the impact of purchasing alliances on product variety and profit sharing in a setting, in which capacity constrained retailers operate in separated markets and select their assortment in a set of differentiated products offered by heterogeneous suppliers (multinationals vs. local SMEs). Retailers may either have independent listing strategies or build a buying group, thereby committing to a joint listing strategy. This alliance may cover the whole product line (full buying group) or only the products of large suppliers (partial buying group). We show that a buying group may enhance the retailers’ buyer power and reduce the overall product variety to the detriment of consumers. Our most striking result is that partial buying groups do not protect the small suppliers from being excluded or from bearing profit losses; they may even be more profitable for retailers than full buying groups.     

Private labels in marketplaces

Regulators are concerned that by introducing their own private labels, dominant online marketplace operators distort competition in their own favor. This paper addresses this concern by studying how online marketplaces differ from classic retailers with a wholesale arrangement. In online marketplaces individual sellers set their own consumer prices, while the marketplace operator collects fees from their sales. I show that when introducing a private label, the marketplace operator does not have an incentive to distort competition and foreclose the outside seller. On the contrary, when introducing a private label, there is an incentive to decrease the fee charged to the outside seller and to vertically differentiate its own product in order to protect the seller’s channel. However, relative to the wholesale model of classic retailers, online marketplace operators offer a lower quality with higher consumer prices, leading to less improvement in consumer surplus and potentially less harm to the outside seller.     

Optimal reserve prices in sealed-bid auctions with reference effects

The reference effect and loss aversion are incorporated into the buyer’s utility in the symmetric independent private value models of sealed-bid auctions. The buyer’s equilibrium bidding strategy and the seller’s optimal reserve price are derived for the first-price and second-price sealed-bid auctions. In both auction mechanisms, the seller’s optimal reserve price and expected revenue are increasing in the reference point. We compare the seller’s expected revenues as well as the optimal reserve prices in the two auctions. The results show that the seller will set a higher optimal reserve price but obtain lower optimal expected revenue in the second-price auction compared to the first-price auction. Further, we extend the model to the gain-seeking case, and endogenize the reference point as the ex-ante expected price of the item in equilibrium. In contrast to the loss-averse case, the seller will set a lower optimal reserve price but obtain higher optimal expected revenue in the second-price auction compared to the first-price auction if the buyers are gain-seeking. With an endogenous reference point, similar results are obtained in terms of revenue comparison between the two auctions.     

Anti-competitive effects of resale-below-cost laws

We show that resale-below-cost laws enable producers to impose industrywide price-floors to retailers. This mechanism suppresses downstream competition but also dampens upstream competition, leading to higher prices. Price-floor may be more profitable for producers than resale price maintenance contracts and, while resale price maintenance may have ambiguous effect on welfare, price-floors always harm welfare. Retailers' buyer power appears as a key element for a price-floor to work out.     

Consumer Decision-making at an Internet Shopbot: Brand Still Matters

Internet shopbots compare prices and service levels at competing retailers, creating a laboratory for analysing consumer choice. We analyse 20,268 shopbot consumers who select various books from 33 retailers over 69 days. Although each retailer offers a homogeneous product, we find that brand is an important determinant of consumer choice. The three most heavily branded retailers hold a $1.72 price advantage over more generic retailers in head-to-head price comparisons. In particular, we find that consumers use brand as a proxy for retailer credibility in non-contractible aspects of the product and service bundle, such as shipping reliability.     

A Simple Search and Bargaining Model of Real Estate Markets

This paper examines the impact of brokers on buyers' and sellers' search behavior and on the transaction prices in real estate markets. It is shown that the seller and the buyer search less intensively if the house is listed with a broker. The seller gets a higher price when he employs a broker, but the increase in price is smaller than the commission fee. More specifically, the portion of the commission covered by the increase in price is directly related to the bargaining powers of the buyer and the seller. In the special case where the price is determined according to the Nash bargaining solution, the increase in price is shown to be half of the commission fee. It is also shown that an increase in the commission rate increases the equilibrium price but decreases the equilibrium search intensities.     

BUYER POWER AND THE ‘WATERBED EFFECT’*

When a buyer is able to obtain lower input prices from a supplier, is it possible that other buyers will have to pay more for the same input as a result? Is this bad for consumers? We present a model that analyzes the conditions under which the asymmetric exercise of buyer power can lead to consumer detriment through raising other buyers' wholesale prices (the ‘waterbed effect’).     

Reverse Price Discrimination with Bayesian Buyers

This paper studies price discrimination under the situation in which buyers' prior valuations are initially observable by a seller but buyers receive further information about a product or service which remains private thereafter. The buyers interpret new information via Bayes' rule. We show that, in this environment, prices are not monotone in buyers' prior valuations. Interestingly, this results in the possibility that a seller intentionally offers a higher price to a low valuation buyer rather than a high valuation buyer (Reverse Price Discrimination). We derive this result in both monopoly and duopoly markets.     

Commodity price inflation, retail pass-through and market power

When commodity prices rise, wholesalers and retailers of products derived from basic commodities respond by passing along at least a portion of the price increase to consumers. In this paper we examine whether firms respond differently to positive commodity price shocks than to negative commodity price shocks; that is, whether commodity price volatility alters market power. We exploit recent volatility in food commodity prices over the period 2007-2010 to investigate how commodity price shocks translate into market power in two different vertically-structured food product industries: potatoes and fluid milk. For potatoes, we find both wholesale and retail market power decreases (increases) during periods of rising (falling) commodity prices. Moreover, price-cost margins widen a substantially greater degree in response to negative shocks than margins narrow in response to positive shocks, indicating that commodity price volatility increases market power. For fluid milk, we find that market power likewise declines during periods of rising commodity prices; however, market power does not significantly change during periods of falling commodity prices, suggesting that commodity price volatility decreases market power.     

One‐Stop Shopping Behavior,Buyer Power and Upstream Merger Incentives

We analyze how consumer preferences for one‐stop shopping affect the (Nash) bargaining relationships between a retailer and its suppliers. One‐stop shopping preferences create ‘demand complementarities’ among otherwise independent products which lead to two opposing effects on upstream merger incentives: first a standard double mark‐up problem and second a bargaining effect. The former creates merger incentives while the later induces suppliers to bargain separately. When buyer power becomes large enough, then suppliers stay separated which raises final good prices. We also show that our result can be obtained when wholesale prices are determined in a non‐cooperative game and under two‐part tariffs.     

Cheap Exclusion in Markets with Multiple Complements

We extend the theory of exclusive dealing in first-mover environments to settings where the incumbent seller’s product is used with multiple complements in a distribution chain and the incumbent can sign exclusive dealing contracts with more than one of them. The model is motivated by the market for biosimilar pharmaceuticals, where incumbent sellers that face a threat of entry can sign exclusionary contracts with both providers and insurance carriers prior to entry. We show that when the incumbent’s complementors are vertically related, it can be profitable for the incumbent to sign exclusive contracts with indirect buyers, who operate downstream from the direct buyers of the product. Under linear pricing, such exclusion is profitable if the pass-through rate is sufficiently low, and under nonlinear pricing and symmetric Nash bargaining, it is profitable for all pass-through rates. Complementors face a more severe coordination problem than independent buyers that can make anticompetitive exclusion more likely and especially cheap.     

The Impact of Upfront Payments on Assortment Decisions in Retailing

There is a contentious debate about the exclusionary effects of upfront payments to be made by manufacturers to place their products on retailers’ shelves. Analyzing a two-stage bargaining process with one downstream retailer and a pool of upstream manufacturers, we find that upfront payments lead to a smaller assortment if the retailer’s bargaining power is high enough and the suppliers’ products are close substitutes.     

Price Strategies for Idiosyncratic Goods—The Case of Housing

We determine the mechanism that a rational, profit-maximizing seller would use to revise his reservation price for a heterogeneous or infrequently exchanged good. For instance, while one dimension of a home's quality may be easily determined in competitive markets (e.g., the valuation of floor size, location, etc.), other dimensions of quality may be idiosyncratic (unit specific) and unobservable by the seller (e.g., aesthetics of the home). Here, a seller of a new or infrequently exchanged housing unit may use sales success information to revise his expectation of the unit's market-determined value and hence revise his reservation price. The rational seller will, upon arrival of the first buyer inspecting the unit, determine a sequence of reservation prices for this and expected subsequent buyers. This price sequence falls for subsequent buyers and starts from a lower initial price if the first buyer arrives later than expected. Through this mechanism, we offer an explanation for price dispersion and vacancy durations in housing markets. While we explicitly model the real estate market here, this price revision mechanism is also applicable to rental markets, labor markets, used car markets, and other markets characterized by heterogeneity and infrequent sales.     

Market structure and business performance: An evaluation of buyer/seller power in the pims database

This paper explores the patterns of buyer and seller structure among business units in the PIMS database and how buyer/seller structure is related to profit outcomes, both long-term through the product life cycle and short-term between periods of boom and recession. Businesses with a favourable structure (few sellers, many buyers buying items of low importance) typically maintain margins through the product life cycle, but if there are many sellers facing few and determined buyers, margins and profitability are likely to deteriorate in recession and to continue to decline through the life cycle.     

Cartelization Through Buyer Groups

Retailers may enjoy stable cartel rents in their output market through the formation of a buyer group in their input market. A buyer group allows retailers to commit credibly to increased input prices, which serve to reduce combined final output to the monopoly level; increased input costs are then refunded from suppliers to retailers through slotting allowances or rebates. The stability of such an ‘implied cartel’ depends on the retailers’ incentives to source their inputs secretly from a supplier outside of the buyer group arrangement at lower input prices. Cheating is limited if retailers sign exclusive dealing or minimum purchase provisions. We discuss the relevancy of our findings for antitrust policy.