The FTC and its state partners say Amazon’s actions allow it to stop rivals and sellers from lowering prices, degrade quality for shoppers, overcharge sellers, stifle innovation, and prevent rivals from fairly competing against Amazon.

The complaint alleges that Amazon violates the law not because it is big, but because it engages in a course of exclusionary conduct that prevents current competitors from growing and new competitors from emerging.

By stifling competition on price, product selection, quality, and by preventing its current or future rivals from attracting a critical mass of shoppers and sellers, Amazon, it is alleged, ensures that no current or future rival can threaten its dominance.

FTC chair Lina M. Khan said: “Our complaint lays out how Amazon has used a set of punitive and coercive tactics to unlawfully maintain its monopolies.

“The complaint sets forth detailed allegations noting how Amazon is now exploiting its monopoly power to enrich itself while raising prices and degrading service for the tens of millions of American families who shop on its platform and the hundreds of thousands of businesses that rely on Amazon to reach them.

“Today’s lawsuit seeks to hold Amazon to account for these monopolistic practices and restore the lost promise of free and fair competition.”

John Newman, deputy director of the FTC’s Bureau of Competition, added: “We’re bringing this case because Amazon’s illegal conduct has stifled competition across a huge swath of the online economy. Amazon is a monopolist that uses its power to hike prices on American shoppers and charge sky-high fees on hundreds of thousands of online sellers.

“Seldom in the history of U.S. antitrust law has one case had the potential to do so much good for so many people.”