The European Commission plans to open an official investigation into a tax deal the Seattle-based e-commerce company has with Luxembourg, the Financial Times is reporting.

[UPDATE: The EC issued a press release Tuesday announcing the official investigation.

National authorities must not allow selected companies to understate their taxable profits by using favourable calculation methods,” said Joaquín Almunia, EC’s vice president in charge of competition policy, in the press release. “It is only fair that subsidiaries of multinational companies pay their share of taxes and do not receive preferential treatment which could amount to hidden subsidies.”]

The investigation will focus on a 2003 tax ruling that allowed Amazon to limit the taxes it paid, the FT reports. The move is part of a much broader probe the European Commission is conducting into the tax deals some of its member countries have struck with big corporations.

Just last week, the EC released a report claiming similar deals that Apple has with Ireland are illegal.