Incredibly, many businesses today still buy and sell supplies and materials with paper invoices, faxes, and checks. It’s a huge opportunity on which the two largest e-commerce companies in the U.S., eBay and Amazon, have not focused. Both companies run marketplaces, but they specialize in consumer-facing goods, not wholesale items and business supplies. Amazon has been running AmazonSupply, a wholesale site, in beta for two years, as CEO Jeff Bezos promotes increasingly flashier schemes around drone delivery, TV shows, mobile phones, and publishing.