Yet Amazon’s dominance extends far beyond retail. It also lends credit, publishes books, designs clothing, and manufactures hardware. Three years ago, it bought Twitch.com, a central player in the $1-billion business of e-sports. And on top of all this, it operates Amazon Web Services, a $12-billion business that rents servers, bandwidth, and computing power to other companies. Slack, Netflix, Dropbox, Tumblr, Pinterest, and the federal government all use Amazon Web Services.

It is, in short, an Everything Store: not only selling goods but also producing them, not only distributing media from its servers but also renting them out to others. And it’s left many experts and analysts wondering: When does Amazon become a a monopoly?

“I think of Amazon as serving almost as the essential infrastructure for the American economy at this point, when it comes to commerce. And that affords Amazon a lot of power and control,” says Lina Khan, a fellow on the Open Markets team at New America, a center-left think tank.