The Commission, which presides over competition policy in the European Union, said on Thursday it had sent a statement of objections to the brewer and that its preliminary view was that the company had abused its dominant position in Belgium.
"Belgian consumers may have had to pay more for their favourite beers. Our preliminary finding is that AB InBev may have deliberately prevented cheaper beer imports out of France and the Netherlands from reaching consumers in Belgium," EU Competition Commissioner Margrethe Vestager said in a statement.
"Such practices would breach EU competition rules, because they deny consumers the benefits of the EU single market – choice and lower prices."
The Commission said the statement of objections did not pre-judge the case and gave AB InBev the opportunity to respond in writing and request a hearing.
Companies found guilty of anti-competitive practices or abuse of market position may have to make commitments or be subject to a fine of up to 30 percent of the sales of the products concerned multiplied by the number of years, with an overall maximum fine of 10 percent of annual global turnover.
AB InBev stressed that the statement of objections was a procedural step and not a final decision. It also said it had been working constructively with the Commission and that integrity and ethics were part of its core values.
The Commission, which opened formal antitrust proceedings in June 2016, said it had identified a number of business practices that prevented Belgian supermarkets and wholesalers from buying in the brands from outside Belgium.
AB InBev, for example, removed French text from cans in the Netherlands and Dutch from cans sold in France to prevent their sale respectively in French and Dutch-speaking parts of Belgium, the Commission said.
A Commission spokesman said AB InBev appeared to have been selling cans with text in both French and Dutch in all three countries, but had modified the labels on certain cans in 2014-2015 to make them purely in French in France and Dutch in the Netherlands.
"In our assessment, our current view is that this was with the purpose of making it more difficult or legally impossible for supermarkets or other wholesalers to sell the products to consumers in Belgium or almost all of Belgium."
The Commission also said that the brewer did not sell or limited the quantity of products sold to Dutch retailers or restricted the availability of promotions if there was a chance the Dutch retailers could ship beer to Belgium.
French supermarkets operator Carrefour and Dutch group Ahold Delhaize have extensive supermarket networks in Belgium.
(Reporting by Philip BlenkinsopEditing by Greg Mahlich)
By Philip Blenkinsop