JD.com's (JD) proposed acquisition of German electronics retailer CECONOMY AG hit a roadblock after the European Commission issued a Statement of Grounds Wednesday, outlining its preliminary concerns that the Chinese e-commerce company may have benefited from foreign subsidies that could distort competition in the European Union.

The Commission said its ongoing investigation suggests JD.com may have received preferential financing, tax incentives and grants from entities potentially attributable to China, which could improve the merged company's competitive position in the EU market.

The Statement of Grounds is a formal step in the investigation and does not prejudge the outcome, the Commission said. JD.com can now respond to the Commission's objections, review the case file and offer commitments, it added.

The Commission opened an in-depth probe into the transaction in May, and a provisional decision is due by Oct. 2.