European regulators are taking a preliminary look at Amazon’s third-party data collection practices as part of an early antitrust probe, European Union officials disclosed today.

The EU is “gathering information”

Margrethe Vestager, the head of the EU’s competition bureau, said during a press conference that the EU has been “gathering information” on how the company uses data from sellers on its third-party marketplace. Regulators want to know whether that data could give Amazon an edge over competitors by providing insight into consumer behavior.

“If you, as Amazon, get the data from the smaller merchants that you host, which can be of course completely legitimate because you can improve your service to these smaller merchants, do you then also use this data to do your own calculations?” Vestager said. “What is the new big thing? What is it that people want? What kind of offers do they like to receive? What makes them buy things?”

Vestager stressed that the probe was still in its “early days,” and that no formal investigation has yet been opened, even though questionnaires have been sent to marketplace participants. But even the first steps of an investigation are likely to give Amazon heartburn. Led by Vestager, the EU has taken a strict stance toward tech companies, recently levying a massive $5 billion fine against Google over alleged anti-competitive practices on Android.

Amazon declined to comment.