In 2017, Amazon's market share of the U.S. e-commerce retail market was 37 percent, and this is expected to increase significantly by 2021. ... Projected retail e-commerce GMV share of Amazon in the United States from 2016 to 2021. CharacteristicMarket share 2019*45% 2018*41% 201737% 201634% 2 more rows 27 Jul 2022