Amazon.com Inc. (NASDAQ:AMZN) shares are dipping Monday after a report that the Federal Trade Commission plans to sue the company over allegations it secretly manipulated ad prices paid by merchants on its platform. Here’s what you need to know.

Amazon.com shares are experiencing downward pressure. Why is AMZN stock retreating?

FTC to Sue Amazon Over Alleged Ad Price Manipulation

The FTC intends to file a lawsuit against Amazon in federal court in Seattle, according to The Wall Street Journal, alleging the company quietly pushed up the minimum price merchants had to pay to advertise on its platform, generating tens of billions of dollars for Amazon over roughly seven years.

More than 20 state attorneys general from both parties are expected to join the case. It would mark the FTC’s third major legal action against Amazon, following a $2.5 billion settlement last year over Prime cancellation practices and a separate monopoly case set to go before a jury next year.