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Price dispersion and consumer search : Evidence from the retail gasoline market and the supermarket industry in France

Abstract : This thesis is an empirical study of price dispersion, namely the fact that a homogenous good can typically be purchased at various prices, in violation of the famous law of one price. The approach belongs to a literature initiated by Stigler (1961), which notes that “price dispersion is (...) the measure of ignorance in the market”. A noteworthy consequence is that simple price observations can be very informative about competition in a market.The first chapter analyses the impact of the creation of a discount chain on the French retail gasoline market. This creation implies that many gas stations are confronted with a sharp price decrease by a competitor. The aggregate reaction, measured at the national level, is weak but it conceals increases and decreases in equivalent proportions The heterogeneity of measured reactions highlights an important market segmentation. Using the same data, the second chapter explores the relevance of models which identify price dispersion with an equilibrium in mixed strategies. Empirically, the rank of competing gas stations is indeed observed to vary over time, and its volatility is positively correlated with the distance that separates the outlets. Dispersion thus increases with a search cost incurred by customers. The chain affiliation of gas stations largely determines their pricing strategies. Retailers which have low price policies are more likely than others to keep prices aligned with nearby competitors, while dispersion measured between more expensive gas stations is positively correlated with diesel cost and the number of sellers in the market. Results thus provide further support the coexistence of a market close to Bertrand competition with a less competitive market, where gas stations take advantage of significant frictions.The last chapter focuses on grocery stores, using data collected from an online price comparison website. Aggregate national chain comparisons that are displayed on the website are found to provide information of little value to consumers given the heterogeneity observed within store level comparison results. These can furthermore vary significantly depending on the set of compared products. Volatility tends to increase with the distance that separates supermarkets, which, as in the case of gasoline, suggests that search cost influence competition. Within local markets, the measured concentration is negatively correlated with price levels, which leads to question its effective relevance in terms of public policies. Price dispersion is found to increase with market price levels, which is consistent with sellers taking advantage of consumer search costs to post higher prices.
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Submitted on : Wednesday, March 21, 2018 - 1:51:08 PM
Last modification on : Friday, May 29, 2020 - 5:06:37 AM


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Etienne Chamayou. Price dispersion and consumer search : Evidence from the retail gasoline market and the supermarket industry in France. Economics and Finance. Université Paris-Saclay, 2017. English. ⟨NNT : 2017SACLX067⟩. ⟨tel-01739697v2⟩



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