Just as Amazon is making a big push in the U.S. to expand its third-party seller program, the European Union has launched an investigation into how the company handles data from those small vendors.  The investigation was announced by Margreth Vestager, the EU’s antitrust chief, according to The New York Times.  She said the EU is investigating whether Amazon uses data from sales by its third-party sellers to tailor its own offerings in ways that allow it to compete unfairly with the smaller business.

The investigation explores Amazon’s dual roles as a merchant and as a platform for other merchants.  Over half of Amazon’s e-commerce sales are from other businesses that sell on its platform, with the remainder sales it makes on its own behalf, according to the report.

Amazon just launched Amazon Storefronts, a new program to promote U.S.-based small and medium-sized businesses selling on the platform.  In addition to promoting the sellers on its site, Amazon is also running a national television ad campaign featuring third party sellers.  The program will initially focus on about 1 million products sold by 20,000 sellers, Amazon said.  On the site, Amazon will also feature the Storefront of the Week, with a highlighted U.S. business, and Meet the Business Owner, a web feature that will introduce sellers.