Amazon operates three core businesses: an online retail marketplace, AWS (cloud computing), and advertising. In retail, Amazon sells products directly to consumers and hosts third-party sellers on its marketplace, with third-party sellers accounting for roughly 61-62% of units sold. Amazon competes on price, selection, and delivery speed, and ties customers in through Prime membership ($14.99/month), which bundles fast shipping with streaming video and music. Amazon also operates physical stores, most notably Whole Foods. AWS provides on-demand cloud infrastructure — compute, storage, databases, AI/ML tools, and more — to businesses and governments on a consumption-based model. AWS carries operating margins around 35%, far above the low-to-mid single-digit margins of the retail segments. Advertising, Amazon's third business, sells sponsored listings, display, and video ads to brands and sellers, benefiting from Amazon's purchase-intent data and high conversion rates. Amazon's retail profitability hinges on fulfillment network efficiency, where lower cost-to-serve per unit drives margin expansion; robotics, automation, and network regionalization are key levers. AWS is Amazon's primary growth driver, with a $142B annualized run rate growing 24% YoY, fueled by enterprise cloud migrations and AI workloads. Amazon is investing heavily across the AI stack, including its own Trainium chips for AI training and inference, the Bedrock managed model platform, and agent infrastructure tools.