MEXICO CITY, March 31 (Reuters) - Carlos Slim's industrial and retail conglomerate Grupo Carso and his banking unit Grupo Inbursa have challenged a ruling by the new telecommunications regulator that says that both hold dominant market positions.
The companies said in statements filed Monday with the Mexican stock exchange that they do not dominate the telecoms market and have filed an injunction against the regulator's ruling.
Mexican billionaire Slim's telecom giant America Movil , which has about 80 percent of Mexico's fixed-line business and some 70 percent of the mobile sector, is considered dominant in its market by the Federal Telecommunications Institute (IFT) but has not challenged that ruling.
Mexico is trying to open up its phone and TV industries to more competition following last year's passage of a major telecoms reform that targets the vast market shares enjoyed by Slim and the country's no. 1 broadcaster, Televisa.
(Reporting by David Alire Garcia and Tomas Sarmiento; Editing by Bernadette Baum)