Walmart's Mexico unit said it was notified by Mexico's federal competition authority that it is being investigated for possible antitrust behaviour in the supply and distribution market of wholesale goods and retail of these goods and services.
Walmart de Mexico, or Walmex, said it has always acted in accordance with applicable law and that its participation in the Mexican market has resulted in lower prices for consumers, benefiting poor families especially.
The federal competition authority Cofece said it could not comment on Walmart's statement.
In a 4 November study, Cofece said there was a need to facilitate the entry of more competitors to the retail market.
"High market concentration favours the purchasing power of large self-service chains compared to their smaller suppliers, which could distort competition in supplier markets," the Cofece study said.
In the study, Cofece identified Walmart and Soriana, and to a lesser degree Chedraui, as the main players with a national presence.