In a press conference on 19 September 2018, EU Commissioner for Competition Margrethe Vestager announced a preliminary investigation into Amazon. At the heart of the potentially abusive conduct is Amazon’s ‘dual role’. One the one hand, Amazon offers a marketplace for third-party sellers to offer their products to consumers. On the other hand, Amazon offers its own products through its marketplace. The Commission’s allegation appears to be that Amazon uses the data it gathers on third-party transactions to boost the sales of its own products. In this short note, I examine where the investigation is coming from, where it may be headed, and which related developments can influence it.