Amazon.com Inc. faces an antitrust complaint from European Union regulators, escalating an investigation into how it handles data from rival sellers on its massive online retail platform.

The European Commission will announce a so-called statement of objections later Tuesday targeting the world’s biggest online retailer, according to people with knowledge of the case who spoke on condition of anonymity.

The EU document will lay out concerns that Amazon shortchanges rival sellers -- raising the risk of a potential fine as high as 10 per cent of yearly sales and a possible order to change its business model. Margrethe Vestager, the EU’s antitrust chief, will announce the filing at a press conference in Brussels.

The move escalates a probe into Amazon’s role as both direct retailer and a host to other online stores. It makes the company the highest profile big tech target for one of the world’s toughest antitrust regulators. Regulators are wrestling with how to act against online giants that critics say run a rigged game when they set the rules for platforms that also host their competitors.

Google was fined more than US$9 billion after nearly a decade of EU investigations. Apple Inc. and Facebook Inc. also face early-stage probes.

Amazon and the European Commission declined to comment.

The Financial Times reported earlier on the timing of the EU move.