Amazon became the second publicly traded U.S. company to reach a $1 trillion market capitalization, after Apple.
Amazon crossed the threshold on September 4, 2018, roughly one month after Apple reached the same valuation. Its share price reflected investor expectations about e-commerce, cloud computing, digital advertising, and subscription services.
Amazon began as an online bookseller founded by Jeff Bezos in 1994. It expanded into a broad marketplace and built Amazon Web Services, whose cloud infrastructure became a major source of revenue and operating profit.
A common mistake is to rank companies by revenue when discussing market capitalization. Market cap measures the value investors assign to all outstanding shares, so a company with lower revenue can still be worth more on the stock market.