“Amazon is a monopolist and it is exploiting its monopolies in ways that leave shoppers and sellers paying more for worse service,” FTC Chair Lina Khan said in a briefing with reporters. “The stakes here are high. There is immediate harm that is ongoing. Sellers are paying $1 of every $2 to Amazon.”

The suit is the fourth the agency has filed this year targeting Amazon, underscoring the determination of the Biden administration to put the growing concentration of corporate power, especially among Big Tech companies, at the heart of economic policy.

The case also represents a career-defining moment for Khan, Biden’s FTC chair, who has long had Amazon in her sights. As a young law student, Khan wrote a seminal paper arguing that the existing antitrust enforcement framework was poorly equipped to tackle the potential harm Amazon poses to competition.

The FTC and a bipartisan slate of states claim Amazon engaged in anticompetitive conduct in two markets — the market for these online superstores that serve consumers and the separate market for sellers.

Merchant Commissions

Amazon’s marketplace is the heart of the company’s e-commerce operations. Third-party merchants, who now account for more than half of the company’s online sales, pay a commission on each sale and have the option of also paying Amazon for services that range from warehousing and shipping to advertising.

Merchants have complained for years about what they see as a one-sided relationship, accusing the company of arbitrarily enforcing its rules and being slow to respond when something goes awry.

Among other things, Amazon bars sellers from offering lower prices on other sites, a policy the FTC says curbs online competition because it forces sellers to raise prices on competing platforms such as Walmart.com for fear of having their products buried in Amazon search results.

The FTC also alleged that Amazon unduly favors its own retail business, as well as marketplace sellers that use the company’s logistics services.

The FTC, which has both antitrust and consumer protection mandates, has been investigating Amazon for potential anticompetitive conduct for several years, asking questions about everything from the company’s marketplace and Prime subscription service to mergers and its cloud computing arm. Top executives met with the FTC’s three commissioners in August to discuss the suit, though no settlement was discussed, according to people familiar with the meetings.

Alexa, Ring

In May, the agency sued the e-commerce giant in two separate cases for failing to delete data about kids collected by its Alexa speakers and illegally spying on users of its Ring doorbells and cameras. Amazon said it disagreed with the FTC’s allegations, but agreed to pay $30.8 million to resolve the cases.

One month later, the FTC again sued Amazon in a consumer protection case, alleging the company duped consumers into signing up for Prime membership and deliberately made it hard to cancel — echoing longstanding complaints from consumer watchdogs. Amazon denies the allegations, and that suit is ongoing.

Amazon has pushed the FTC to recuse Khan from its case, citing her academic work and prior statements about the company. It has also accused the agency of harassing founder Jeff Bezos and the company’s Chief Executive Officer Andy Jassy with document and interview requests.

The FTC is separately investigating Amazon’s proposed $1.65 billion acquisition of Roomba vacuum maker iRobot Corp. as are European antitrust authorities. In July, the companies renegotiated the price of the deal as the regulatory reviews remain ongoing.

“If we succeed, competition will be restored and people will benefit from lower prices, better quality,” Khan said Tuesday.