Ifetel, Mexico’s regulator, said it had identified dominant players in the country’s telecoms and broadcasting markets, according to Reuters. It paves the way for new and tougher regulation on those deemed to have significant market power.

America Movil and Telemex – owned by billionaire Carlos Slim – and broadcaster Televisa, controlled by media mogul Emilio Azcárraga’s, are expected to be hit by the new rules.

America Movil has 70 per cent of Mexico’s mobile subscribers, while Telmex has 80 per cent of fixed-line subscribers.

Telvisa has 70 per cent of the terrestrial TV market and about half of the pay-TV sector.

Cracking down on anti-competitive behaviour has been a priority for President Enrique Pena Nieto, now in his second year of office.

Ifetel, set up by the new administration, has more powers than its predecessor to address anti-trust behaviour in telecoms and create a more level playing field.

The regulator has not yet announced what punishment it will mete out to those identified as dominant, but there has been some speculation they could even be broken up.

One obvious and less painful remedy for America Movil, however, would be to force it to allow smaller firms access to its infrastructure.

Opening up the markets might also work to Slim’s advantage if he can gain a stronger foothold in broadcasting. That would open up the possibility of bundling in TV services with mobile and fixed-line offerings.