This study examines the effect of Walmart on price dispersion across US cities. Although US retail architecture has been changed over the past two decades by the expansion of big-box chain-stores such as Walmart, the impact of such market consolidation on price dispersion is not examined rigorously. Using opening/conversion dates of Walmart and good-specific quarterly retail prices for 101 US cities over 25 years, we examine the role of Walmart on price dispersion across US cities. Our analysis shows that price dispersion in a city-pair increases when Walmart enters one of the cities in the pair. When Walmart enters the other city of the city-pair, price dispersion falls from that increased level but the fall is not enough to bring the price dispersion back to the level where there is no Walmart in the city-pair. This finding implies that Walmart drives down prices in ‘early’ cities more than in ‘late’ cities and that prevalence of big-box stores may be one of the reasons for price dispersion across cities.

这项研究考察了沃尔玛对美国各城市价格差异的影响。尽管在过去的二十年中，随着沃尔玛等大型连锁店的扩张，美国的零售体系发生了变化，但这种市场整合对价格分散的影响并未得到严格检查。使用沃尔玛的开业/转换日期以及25年内美国101个城市的特定季度零售价格，我们研究了沃尔玛在美国城市价格分散中的作用。我们的分析表明，当沃尔玛进入一对城市中的一个城市时，城市对中的价格差异会增加。当沃尔玛进入城市对的另一个城市时，价格离散度从上升的水平下降，但下降幅度不足以使价格离散度回到城市对中没有沃尔玛的水平。