E-commerce giant Amazon’s one-day shipping is poised to pose a big threat to retailers, according to Morgan Stanley. “Amazon One Day delivery is a threat that makes us incrementally cautious on our Retail coverage,” Simeon Gutman, the bank’s analyst said in a note on Tuesday. “We believe Amazon’s shift to one-day delivery will again raise consumers’ expectations (as the introduction of two-day delivery did 14 years ago).” Amazon started rolling out free one-day shipping on over 10 million products for its Prime members in June this year. The company announced Tuesday it will start delivering grocery products within a two-hour window to all Prime members. While faster delivery increases Amazon’s costs, investors have cheered the move, pushing the stock up more than 18% this year. Read more at CNBC.