Mexico's government presented a major telecommunications reform bill on Monday that aims to loosen Mexican billionaire Carlos Slim's hold over the phones sector, and prize open top broadcaster Televisa's grip of the airwaves.
Below are a list of key players affected by the reform:
AMERICA MOVIL: Controlled by Carlos Slim, the world's richest man, America Movil has 70 percent of Mexico's mobile market and 80 percent of its fixed phone lines.
The luster of Slim's flagship telecoms company has begun to fade of late as increased competition, disappointing investments and new regulations have dealt a blow to the one-time investor darling as it has trailed Mexico's benchmark IPC index. America Movil shares are down more than 10 percent for the year.
Weaker-than-expected fourth quarter profit knocked an estimated $4 billion off Slim's $73 billion fortune.
It remains to be seen what effect the reform will have on the company's bottom line as regulators seek to cut the fees the company can charge competitors to connect to its network, while allowing rivals to charge America Movil more in a process known as asymmetric regulation.
America Movil reported revenue of 775 billion pesos ($60 billion) and a profit of 91.4 billion pesos in 2012.
TELEVISA: Mexican broadcaster Televisa , controlled by media mogul Emilio Azcarraga, is the world's biggest producer of Spanish-language content and one of the companies in regulators' crosshairs.
Televisa has said it controls about 60 percent of Mexico's broadcasting market, with rival TV Azteca controlling most of the rest.
Televisa has competed with TV Azteca since its smaller rival was privatized by the government about 20 years ago, forcing Televisa to trim costs and improve broadcasting quality.
Televisa has said it supports the reform, which will open up the playing field in the narrow television sector. The telecoms shakeup should open the door for Televisa's mobile-phone business Iusacell, which has a roughly 6 percent share of the Mexican market, to thrive.
The broadcaster reported revenue of 69.3 billion pesos and a profit of 10.1 billion pesos in 2012.
TV AZTECA: Owned by Mexican billionaire Ricardo Salinas, TV Azteca is the other main player in Mexico's TV market, and joined forces with Televisa investing in Iusacell.
TELEFONICA: Spanish telecoms giant Telefonica is a big potential winner of the reform. The company is trying to loosen Slim's grip over Latin American markets, and raise its 20 percent share in Mexico.
($1 = 12.8704 pesos at end December)
(Compiled by Gabriel Stargardter in Mexico City; Editing by Phil Berlowitz)