FTC’s Amazon Antitrust Suit Likely to Be Filed in September

The Federal Trade Commission is likely to sue Amazon.com Inc. later this month, capping a four-year antitrust investigation into the company, people familiar with the matter said Tuesday.

The antitrust suit is expected to target the online retail giant’s popular marketplace, where third-party merchants, who now account for more than half of the company’s online sales, pay a commission on each sale, according to the people, who asked not to be named discussing the potential suit. Merchants have complained that Amazon unfairly ties access to its marketplace with its logistics service.