Advertising, along with growth in third-party seller services, subscription revenue, and operating leverage over its fixed cost base, has enabled Amazon's North American retail division to expand its profit margin to 7% over the last 12 months. Through the rest of 2025, there is plenty of room for this expansion to keep occurring, which will have a large impact on profitability given how much revenue the division generates ($400 billion over the last 12 months). Even slight profit margin enhancements mean b ...