Microsoft develops and licenses consumer and enterprise software. It is known for its Windows operating systems and Office productivity suite. The company is organized into three overarching segments: productivity and business processes (legacy Microsoft Office, cloud-based Office 365, Exchange, SharePoint, Skype, LinkedIn, Dynamics), intelligence cloud (infrastructure- and platform-as-a-service offerings Azure, Windows Server OS, SQL Server), and more personal computing (Windows Client, Xbox, Bing search, display advertising, and Surface laptops, tablets, and desktops). Through acquisitions, Microsoft owns Xamarin, LinkedIn, and GitHub. It reports revenue in product and service and other revenue on its income statement.

Amazon is among the world's highest-grossing online retailers, with $233 billion in net sales and $408 billion in estimated global gross merchandise volume (GMV) in 2018. Online product and digital media sales accounted for 53% of net revenue in 2018, followed by commissions, related fulfillment and shipping fees, and other third-party seller services (18%), Amazon Web Services' cloud compute, storage, database, and other offerings (11%), Prime membership fees and other subscription-based services (6%), product sales at Whole Foods and other physical store retail formats (7%), and advertising services and cobranded credit cards (4%). International segments constituted 32% of Amazon's non-AWS sales in 2018, led by Germany, the United Kingdom, and Japan.

Alphabet is a holding company, with Google, the Internet media giant, as a wholly owned subsidiary. Google generates 99% of Alphabet revenue, of which more than 85% is from online ads. Google's other revenue is from sales of apps and content on Google Play and YouTube, as well as cloud service fees and other licensing revenue. Sales of hardware such as Chromebooks, the Pixel smartphone, and smart homes products, which include Nest and Google Home, also contribute to other revenue. Alphabet's moonshot investments are in its other bets segment, where it bets on technology to enhance health (Verily), faster Internet access to homes (Google Fiber), self-driving cars (Waymo), and more. Alphabet's operating margin has been 25%-30%, with Google at 30% and other bets operating at a loss.

Berkshire Hathaway is a holding company with a wide array of subsidiaries engaged in diverse activities. The firm's core business segment is insurance, run primarily through Geico, Berkshire Hathaway Reinsurance Group and Berkshire Hathaway Primary Group. Berkshire has used the excess cash thrown off from these and its other operations over the years to acquire Burlington Northern Santa Fe (railroad), Berkshire Hathaway Energy (utilities and energy distributors), and the firms that make up its manufacturing, service, and retailing operations (which include five of Berkshire's largest noninsurance pretax earnings generators: Precision Castparts, Lubrizol, Clayton Homes, Marmon and IMC/ISCAR). The conglomerate is unique in that it is run on a completely decentralized basis.

Alibaba is the world's largest online and mobile commerce company, measured by GMV (CNY 5.7 trillion/$846 billion for the fiscal year ended March 2019). It operates China's most-visited online marketplaces, including Taobao (consumer-to-consumer) and Tmall (business-to-consumer). Alibaba's China marketplaces accounted for 68% of revenue in fiscal 2019, with Taobao generating revenue through advertising and other merchant data services and Tmall deriving revenue from commissions. Additional revenue sources include international retail/wholesale marketplaces (7%), cloud computing (7%), digital media and entertainment platforms (6%), Cainiao logistics services (4%), and innovation initiatives/other (1%). Mobile GMV accounted for roughly 85% of consolidated GMV in fiscal 2018.