Business-to-business (B2B) e-commerce in which businesses focus on selling to other businesses, is the largest form of e-commerce, with over $5.7 trillion in transactions in the United States (see Figure 1.4 on page 60) and about €12.4 trillion worldwide in 2014. This is a small portion of total B2B commerce (which remains largely non automated), suggesting that B2B e-mommerce has significant growth potential. The ultimate zden size of B2B e-commerce is potentially huge. There are two primary business models used within the B2B arena: Net marketplaces, which include e-distribumors, e-procure- ment companies, exchanges and industry consortia, and private industriar networks.