Mexico's wireless subscribers rose 11.8% year on year to 79.4 million at the end of March, according to data from the country's four mobile operators.

Market leader Telcel, a unit of Latin America's largest mobile-phone company America Movil SAB (AMX), said in its first-quarter earnings report that its subscriber base grew 11.6% to 57.53 million, while its market share was unchanged at 72.5%.

America Movil is controlled by Mexican billionaire Carlos Slim, who also owns Mexico's largest fixed-line telephone company, Telefonos de Mexico SAB (TMX).

The local unit of Spain's Telefonica SA (TEF), which operates under the Movistar brand, grew its client base 17% to 15.52 million at the end of March. The company's market share rose to 19.5% from 18.7%.

The No. 3 operator, Grupo Iusacell (CEL.MX), which is owned by Mexican media and retail tycoon Ricardo Salinas Pliego, saw its subscriber base shrink nearly 10.7% to 3.54 million after the company disconnected prepaid subscribers who weren't using their phones during the fourth quarter. That caused Iusacell's market share to slip to 4.5% from 5.6% a year earlier.

The smallest operator, Nextel Mexico, a unit of wireless carrier NII Holdings Inc (NIHD), grew 24.1% to 2.82 million clients.

Prepaid subscribers represented 88.4% of total wireless subscribers at the end of March, and the more lucrative postpaid clients 11.6%.

Telefonica said in its first-quarter earnings release Wednesday that Mexico's wireless penetration rate stood at 72% at the end of the quarter, an eight-percentage-point gain from March 2008, but flat compared with the end of December.

Telefonica attributed the slowdown in the wireless market to "lower commercial activity following the Christmas campaign and the country's current economic situation."

The Bank of Mexico expects the economy to shrink between 3.8% and 4.8% this year due to a recession in the U.S. and weak international trade flows as a result of the global financial crisis.

-By Ken Parks, Dow Jones Newswires; 52-55-5001-5723; ken.parks@dowjones.com