Amazon Web Services has been providing most of the company's operating income over the past four years. It didn't meet analyst expectations in the third quarter of 2019, and its growth seems to be slowing down a bit, but it still posted $9 billion in sales.

The FTC refused to confirm the investigation. As Bloomberg notes, though, AWS sells various products on top of its basic offerings, such as databases and machine-learning tools, competing with software companies selling similar products. It also works with some of those software companies, which, in turn, may also be working with other cloud providers. The FTC may be looking into whether Amazon is favoring the companies that work with it exclusively and is punishing rivals that work with its cloud competitors. Of course, that's just a possible angle, and the investigation may not lead to a fine if the FTC finds that AWS is acting completely above board.