Amazon was the second U.S. company to reach a $1 trillion market capitalization after Apple, crossing the threshold in September 2018.
Amazon's valuation reflected the scale of its online marketplace, cloud-computing division Amazon Web Services, advertising business, and subscription services. Its shares briefly reached the level on September 4, 2018.
Amazon began as an online bookstore founded by Jeff Bezos in 1994. It expanded into many categories and built a global logistics network, while AWS became a major provider of computing infrastructure for other organizations.
The wording matters: Amazon was not the first company anywhere to reach $1 trillion, because Apple had already done so. Alphabet and Microsoft also joined the trillion-dollar group later in 2018.