BOSTON, Mass. (SHNS)–Attorney General Andrea Campbell joined 16 other attorneys general and the Federal Trade Commission in filing an antitrust lawsuit against Amazon on Tuesday, alleging the e-commerce giant unfairly stopped competition.

The complaint alleges that Amazon violated the law by preventing competitors from growing and new competitors from emerging, through stopping sellers from lowering prices, degrading quality for shoppers, overcharging sellers and stifling innovation.

“Amazon’s far-reaching schemes impact hundreds of billions of dollars in retail sales every year, touch hundreds of thousands of products sold by businesses big and small and affect over a hundred million shoppers,” says a release from the Federal Trade Commission.

The FTC and states allege that Amazon’s tactics include measures that punish sellers and deter other online retailers from offering prices lower than Amazon, which keeps prices higher across the internet. The FTC release says if Amazon discovers a seller is offering lower-priced products elsewhere, the internet giant can bury those sellers far down in Amazon’s search results, so they become difficult for shoppers to find.

They also allege that the company conditions sellers to obtain “Prime” eligibility for their products, which has made it more expensive for sellers on Amazon to also offer their products on other platforms.

“Amazon has become dominant as an online superstore. But — out of view from the average person, family, or business — Amazon has used that dominance to inflate prices, coerce third-party sellers, and stifle competition,” Campbell said in a statement. “We are joining today’s lawsuit against Amazon to make clear that the AG’s Office will always take on corporate greed and protect consumers.”

In addition to Massachusetts, Connecticut, Delaware, Maine, Maryland, Michigan, Minnesota, New Jersey, New Hampshire, New Mexico, Nevada, New York, Oklahoma, Oregon, Pennsylvania, Rhode Island, and Wisconsin joined the FTC’s lawsuit.