While the retail grocery landscape shifts continuously, the top three largest traditional grocery and supermarket operators in the United States by overall market share and sales revenue are Walmart, The Kroger Co., and Costco Wholesale. Walmart dominates the broader food retail space through its massive supercenter footprint, while Kroger operates traditional supermarket chains across multiple regional banners like Harris Teeter and Smith's. Costco commands massive market share through its warehouse club model, which moves immense volumes of grocery items annually.