Amazon Business, launched in April 2015, this week announced that it had reached the 1 million customer milestone. "This is rapid growth," said Ray Wang, principal analyst at Constellation Research. It's attributable in part to a crossover effect from the large number of B2C customers Amazon has, he said. Amazon Business offers business-only pricing on millions of products, and access to more than 85,000 business sellers. Customers include hospitals, educational institutions, laboratories, daycare centers, government agencies, restaurants, Fortune 50 companies and sole proprietors.