Key Takeaways COST's May net sales rose 6.8% to $20.97B, with total comparable sales up 4.3% year over year. E-commerce comparable sales surged 11.6%, highlighting momentum in Costco's digital business. COST trades at a 51.44 forward P/E, well above peers and its own median, signaling a stretched valuation.Costco Wholesale Corporation’s (COST) May sales results offer fresh insight into the retail giant’s current performance. Known for its steady growth and strong position in the warehouse club space, Cost ...