(Updates with closing share prices, background and analyst comment)

MEXICO CITY -(Dow Jones)- Mexican media company Grupo Televisa SAB (TV) said Friday it will partner with cable operator Megacable Holdings SAB (MEGA.MX) and the local unit of Spain's Telefonica SA (TEF) to bid in an upcoming auction of dark fiber to be leased by state-run electric utility Comision Federal de Electricidad.

Televisa said in a press release that the three companies will form a consortium of equal equity stakes if their joint bid is successful.

Televisa's CPO shares closed virtually unchanged at 52.14 pesos ($4.14) Friday, while Megacable's shares fell 2.4% to MXN29.10.

The government is tendering 20-year leases for 19,647 kilometers of dark fiber owned by the utility along three routes: Mexico's Pacific coast, the center of the country, and the Gulf coast. Dark fiber is unused fiber on the network.

The government expects to announce the winners of the auction on June 9 and has set a minimum bid price of MXN859 million for the three routes.

The auction is expected to help smaller carriers in the Mexican telecommunications market that lack coverage and infrastructure to compete against the country's largest fixed-line operator, Telefonos de Mexico (TMX).

Telmex, as the company is known, has a nationwide network and controls about 82% of the country's fixed phone lines with about 15.9 million lines in service at the end of last year.

Rivals frequently have to use Telmex's infrastructure to provide phone service to their clients. The fees they pay to connect to the Telmex network have been a source of conflict among carriers for years.

Televisa and Megacable, Mexico's largest cable TV providers, also offer telephone service and Internet. Telefonica controls the country's No. 2 mobile operator and has a small but rapidly growing fixed-line subsidiary in Mexico.

Mexico City-based brokerage Ixe Casa de Bolsa said in a note that a successful bid by the Televisa consortium might cause interconnection rates to fall between 15% and 25% as well as reduce traffic over Telmex's network.

"The impact of the previous suppositions on Telmex's revenue would be limited because the loss in revenue would be about 1% of its total sales," Ixe analyst Manuel Jimenez wrote.

(Ken Parks contributed to this article)

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