Amazon.com Inc.'s /zigman2/quotes/210331248/composite AMZN -2.08% "Just Walk Out" technology, which allows shoppers to bypass checkout lines when making purchases, has launched at Sainsbury, the first third-party retailer outside of the U.S. to offer the feature. Sainsbury's Holborn Circus location has been retrofitted with the technology, also a first, and has been transformed into a SmartShop Pick & Go that allows customers to scan their SmartShop app upon entry and exit to purchase items. Amazon Prime membership is not required to shop at the location. Earlier this month, Amazon partnered with Starbucks Corp. /zigman2/quotes/207508890/composite SBUX -1.25% to launch a new concept that includes Starbucks Pickup and Amazon Go capabilities. Sainsbury shares have rallied 29% for the year to date. Amazon stock is up 7.6%. And the benchmark S&P 500 index /zigman2/quotes/210599714/realtime SPX -1.48% has gained 22.3% for the period.