The US government and 17 states are suing Amazon in a landmark monopoly case reflecting years of allegations that the e-commerce giant abused its economic dominance and harmed fair competition.

The groundbreaking lawsuit by the Federal Trade Commission and 17 attorneys general marks the US government's sharpest attack yet against Amazon, a company that started off selling books on the internet but has since become known as "the everything store," expanding into selling a vast range of consumer products, creating a globe-spanning logistics network and becoming a powerhouse in other technologies such as cloud computing.

The complaint alleges Amazon unfairly promotes its own platform and services at the expense of third-party sellers who rely on the company's e-commerce marketplace for distribution.

For example, according to the FTC, Amazon has harmed competition by requiring sellers on its platform to purchase Amazon's in-house logistics services in order to secure the best seller benefits, referred to as "Prime" eligibility. It also claims the company anticompetitively forces sellers to list their products on Amazon at the lowest prices anywhere on the web, instead of allowing sellers to offer their products at competing marketplaces for a lower price.

That practice is already the subject of a separate lawsuit targeting Amazon filed by California's attorney general last year.

Because of Amazon's dominance in e-commerce, sellers have little option but to accept Amazon's terms, the FTC alleges, resulting in higher prices for consumers and a worse consumer experience. Amazon also ranks its own products in marketplace search results higher than those sold by third parties, the FTC said.

Amazon is "squarely focused on preventing anyone else from gaining that same critical mass of customers," FTC Chair Lina Khan told reporters Tuesday. "This complaint reflects the cutting edge and best thinking on how competition occurs in digital markets and, similarly, the tactics that Amazon has used to suffocate rivals, deprive them of oxygen, and really leave a stunted landscape in its wake."

The states involved in the case are Connecticut, Delaware, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New Hampshire, New Mexico, Nevada, New York, Oklahoma, Oregon, Pennsylvania, Rhode Island, and Wisconsin.

The complaint was filed in the US District Court for the Western District of Washington, and seeks a court order blocking Amazon from engaging in the allegedly anticompetitive behavior. Khan declined to say Tuesday whether the agency will be seeking a breakup of the company, saying the case is currently focused on proving Amazon's liability under federal antitrust law.

The suit makes Amazon the third tech giant after Google and Meta to be hit with sweeping US government allegations that the company spent years violating federal antitrust laws, reflecting policymakers' growing worldwide hostility toward Big Tech that intensified after 2016. The litigation could take years to play out. But just as Amazon founder Jeff Bezos and his spectacular wealth have inspired critics to draw comparisons to America's Gilded Age, so may the FTC lawsuit come to symbolize a modern repeat of the antitrust crackdown of the early 20th century.

In a release, Khan accused Amazon of using "punitive and coercive tactics" to preserve an illegal monopoly.

"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," Khan said. "Today's lawsuit seeks to hold Amazon to account for these monopolistic practices and restore the lost promise of free and fair competition."

"Today's suit makes clear the FTC's focus has radically departed from its mission of protecting consumers and competition. The practices the FTC is challenging have helped to spur competition and innovation across the retail industry, and have produced greater selection, lower prices, and faster delivery speeds for Amazon customers and greater opportunity for the many businesses that sell in Amazon's store,"said David Zapolsky, Amazon's Senior Vice President of Global Public policy and General Counsel. "If the FTC gets its way, the result would be fewer products to choose from, higher prices, slower deliveries for consumers, and reduced options for small businesses—the opposite of what antitrust law is designed to do. The lawsuit filed by the FTC today is wrong on the facts and the law, and we look forward to making that case in court."

For years, Amazon's critics including US lawmakers, European regulators, third-party sellers, consumer advocacy groups and more have accused the company of everything from mistreating its workers to forcing its third-party sellers to accept anticompetitive terms. Amazon has unfairly used sellers' own commercial data against them, opponents have said, so it can figure out what products Amazon should sell itself. And the fact that Amazon competes with sellers on the very same marketplace it controls represents a conflict of interest that should be considered illegal, many of Amazon's critics have said.

The lawsuit represents a watershed moment in Khan's career. She is widely credited with kickstarting antitrust scrutiny of Amazon in the United States with a seminal law paper in 2017. She later helped lead a congressional investigation into the tech industry's alleged competition abuses, detailing in a 450-page report how Amazon — as well as Apple, Google and Meta — enjoy "monopoly power" and that there is "significant evidence" to show that the companies' anticompetitive conduct has hindered innovation, reduced consumer choice and weakened democracy.

The investigation led to a raft of legislative proposals aimed at reining in the companies, but the most significant ones have stalled under a barrage of industry lobbying and decisions by congressional leaders not to bring the bills up for a final vote.

Lawmakers' inaction has left it to antitrust enforcers to police the tech industry's alleged harms to competition. In 2021, President Joe Biden stunned many in Washington when he tapped Khan not only to serve on the FTC but to lead the agency, sending a signal that he supported tough antitrust oversight.

Since then Khan has taken an aggressive enforcement posture, particularly toward the tech industry. Under her watch, the FTC has sued to block numerous tech acquisitions, most notably Microsoft's $69 billion deal to acquire video game publisher Activision Blizzard. It has moved to restrict how companies may collect and use consumers' personal information, and warned them of the risks of generative artificial intelligence.

Throughout, the FTC has scrutinized Amazon — suing the company in June for allegedly tricking millions of consumers into signing up for Amazon Prime and reaching multimillion-dollar settlements in May with the company over alleged privacy violations linked to Amazon's smart home devices.

But the latest suit against Amazon may rank as the most significant of all, because it drives at the heart of Amazon's e-commerce business and focuses on some of the most persistent criticisms of the company. In a sign of how threatening Amazon perceived Khan's ascent to be, the company in 2021 called for her recusal from all cases involving the tech giant.

Khan has resisted those calls. On Tuesday, the FTC said it held a unanimous 3-0 vote authorizing the lawsuit; Khan was among those voting to proceed.