Amazon.com Inc. /zigman2/quotes/210331248/composite AMZN +2.49% said Wednesday it is launching Amazon PayCode in the U.S., which allows customers to pay for online purchases in cash at Western Union Co. /zigman2/quotes/206269665/composite WU +0.19% locations. Amazon said 80% of Americans live within five miles of one of Western Union's 15,000 locations. Western Union's stock rallied 3.5% in premarket trading, while Amazon shares slipped 0.2%. The ecommerce giant said Amazon Cash, which allows customers to load cash into their Amazon Balance for making online purchases, is also now available in cash-loading locations. Amazon said PayCode has already been available in 19 countries. Amazon's stock has rallied 21.3% year to date through Tuesday, while Western Union shares have run up 34.0% and the S&P 500 /zigman2/quotes/210599714/realtime SPX +1.60% has gained 19.9%.