Abstract—Approximately 20 years have passed since physical grocery retailers entered the online grocery market. Consumers’ online shopping demand has continued to increase since then. Thus, retailers, especially larger retailers, have had to invest in building networks in online retailing. However, it is not easy to build networks to earn profit. This study considers how to create valuable networks in view of industry concentration based on the U.S. and Japan. It also discusses the typical types of networks by comparing these cases. It then identifies marketing issues by type and examines one of these and identifies the relational model by utilizing marketing aspects.