Amazon.com, Inc. is an American multinational technology company based in Seattle, Washington that focuses on e-commerce, cloud computing, digital streaming and artificial intelligence. It is considered one of the Big Four technology companies along with Google, Apple and Facebook. Amazon is known for its ability to disrupt well-established industries through technological innovation and mass scale. It is the largest e-commerce marketplace, AI assistant provider, and cloud computing platform in the world as measured by revenue and market capitalization. Amazon is additionally the largest Internet company by revenue in the world and the second largest employer in the United States. It is currently the 2nd most valuable company in the world by market capitalization. Amazon has separate retail websites for some countries and also offers international shipping of some of its products to certain other countries. 100 million people subscribe to Amazon Prime. In 2015, Amazon surpassed Walmart as the most valuable retailer in the United States by market capitalization. In 2017, Amazon acquired Whole Foods Market for $13.4 billion, which vastly increased Amazon's presence as a brick-and-mortar retailer.