Mexico's phone and television markets, long dominated by Carlos Slim and his rivals, are facing a game-changing shakeup that could be announced in days, according to one of the political leaders tasked with drafting the reform.
"This (reform) changes the whole board game," Gustavo Madero, chairman of the conservative opposition National Action Party (PAN), told Reuters in an interview.
The leaders of President Enrique Pena Nieto's Institutional Revolutionary Party (PRI) and Mexico's two main opposition parties are currently preparing the telecoms reform, which should be brought to Congress in days, not weeks, Madero said.
Slim, the world's richest man, controls about 70 percent of Mexico's cell phone market and about 80 percent of the fixed lines through his phone giant America Movil .
Televisa, controlled by media tycoon Emilio Azcarraga, has about 60 percent of the broadcasting market, while Ricardo Salinas' TV Azteca has most of the rest.
"There's no other country that I know in the world - perhaps the communist countries - where so few hands have so much control over the broadcasting media," said Madero.
Pena Nieto took office on December 1, pledging to shake up competition in Mexico, particularly the telecommunications industry and the state-run oil monopoly, Pemex.
Shortly afterwards he unveiled a pact in which the leaders of the PRI and the main opposition parties pledged to work together on a broad program of economic reforms.
Madero, who is the spokesman for the alliance known as the 'Pact for Mexico' said the entrenched interests at play, coupled with the three parties' desire to reform the sector from top to bottom, explain why the rule changes are taking time.
"We know this is going to affect interests, that's why we're taking so much care," he said of the reform, which has been expected in Congress at any moment for several weeks.
The reform is more than 90 percent ready, Madero said.
"We are now working on the legal design and the detail of the basic concepts ... on which, in general, we have reached a consensus," he added.
Madero declined to give details of the content of the reform but he said it intends to foster competition and open the sector up to more foreign investment.
Concerns about how the planned reform might affect Televisa and America Movil have weighed on both companies' share prices in recent days.
America Movil, Slim's principal cash cow, has seen its share price decline some 10.5 percent since the start of the year. Disappointing fourth-quarter results have also taken their toll on the company's stock.
Televisa shares have recently touched multi-year highs but on Wednesday fell more than 3 percent after a UBS analyst cut the bank's recommendation for the stock to neutral, citing in part the pending reform.
(Additional reporting by Tomas Sarmiento and Miguel Gutierrez; Editing by Nick Zieminski)