Costco’s remarkably steady growth—a 6.6% compound annual growth rate (CAGR) in the past five years, and 6.5% projected for the next five—underscores consistent execution of a simply stated mission: “To continually provide our members with quality goods and services at the lowest possible prices.” The company describes its approach to pricing as seeking “to maintain what we believe is a perception among our members of our ‘pricing authority’ on quality goods—consistently providing the most competitive values.” Shoppers place deep trust in that authority, leading to baskets and trips that grow over time. This ability to get more out of stores as time goes on is vital because Costco is no longer building new sites as aggressively as it once did. Sometimes criticized for being relatively underdeveloped in e-commerce—and long thought to be especially vulnerable to that channel of trade—it really isn’t turning out that way. E-commerce accounts for about 4% of Costco’s overall sales, and a partnership with Instacart providing grocery delivery is growing in “high double digits” off a small base, officials said recently.