Competing with Costco and Sam's Club: Warehouse Club Entry and Grocery Prices

Prior research shows grocery stores reduce prices to compete with Walmart Supercenters. This study finds evidence that the competitive effects of two other big box retailers – Costco and Walmart-owned Sam's Club – are quite different. Using city-level panel grocery price data matched with a unique data set on Walmart and warehouse club locations, we find that Costco entry is associated with higher grocery prices at incumbent retailers, and that the effect is strongest in cities with small populations and high grocery store densities. This could be explained by a segmented-market model, or by incumbents competing with Costco along non-price dimensions such as product quality or quality of the shopping experience. We find no evidence that Sam’s Club entry affects grocery stores’ prices, consistent with Sam’s Club’s focus on small businesses instead of consumers.

The skinny on big box retailing: Wal-Mart, warehouse clubs, and obesity

Research attributes much of the rise in obesity to technological progress reducing the cost of food consumption. We examine this hypothesis in the context of Walmart Supercenters, whose advancements in retail logistics have translated to substantial reductions in food prices. Using data from the Behavioral Risk Factor Surveillance System matched with Walmart Supercenter entry dates and locations, we examine the effects of Supercenters on body mass index (BMI) and obesity. We account for the endogeneity of Walmart Supercenter locations with an instrumental variables approach that exploits the unique geographical pattern of Supercenter expansion around Walmart’s headquarters in Bentonville, Arkansas. An additional Supercenter per 100,000 residents increases average BMI by 0.25 units and the obesity rate by 2.4 percentage points. These results imply that the proliferation of Walmart Supercenters explains 11% of the rise in obesity since the late 1980s, but the resulting increase in medical expenditures offsets only a small portion of consumers’ savings from shopping at Supercenters

The skinny on big box retailing: Wal-Mart, warehouse clubs, and obesity

Research attributes much of the rise in obesity to technological progress reducing the cost of food consumption. We examine this hypothesis in the context of Walmart Supercenters, whose advancements in retail logistics have translated to substantial reductions in food prices. Using data from the Behavioral Risk Factor Surveillance System matched with Walmart Supercenter entry dates and locations, we examine the effects of Supercenters on body mass index (BMI) and obesity. We account for the endogeneity of Walmart Supercenter locations with an instrumental variables approach that exploits the unique geographical pattern of Supercenter expansion around Walmart’s headquarters in Bentonville, Arkansas. An additional Supercenter per 100,000 residents increases average BMI by 0.25 units and the obesity rate by 2.4 percentage points. These results imply that the proliferation of Walmart Supercenters explains 11% of the rise in obesity since the late 1980s, but the resulting increase in medical expenditures offsets only a small portion of consumers’ savings from shopping at Supercenters