America Movil SAB, the Mexican telecommunications firm, plans to make capital expenditures of $8.5 billion to $9 billion in 2012 as part of its investment plan in networks and focus strategy on subscriber growth.

We want to take advantage of 2012, chief executive Daniel Hajj told analysts on a call, a day after the company reported a 36 percent drop in profit. We're going to invest a lot, he added.

The firm, controlled by billionaire Carlos Slim, will continue to place importance on growth, without neglecting its profit margins. We are really focused on growth, and are going to try to capture new subscribers in Latin America, Hajj said.

Earlier, it had reported fourth-quarter profit that missed analysts' estimates as costs rose to recruit new subscribers and service debt. Fourth-quarter net income slid to 16.3 billion pesos ($1.3 billion) from 25.5 billion pesos a year earlier.

A weaker peso and higher interest expenses boosted financing costs fourfold to 11.1 billion pesos, hurting profit. Sales rose 12 percent to 182 billion pesos, beating the 173 billion-peso average of analyst estimates.

America Movil added 1.6 million postpaid subscribers last year to 34.7 million, a 21% increase over 2010. The growth in postpaid customers carries a higher cost than prepaid customers as the company finances the devices.

America Movil ended the quarter with 242 million mobile-phone customers. Brazil had the biggest net gain in the quarter among the 18 countries where America Movil operates, adding 2.9 million new subscribers.

It spent 121 billion pesos ($8.7 billion) in 2011 on investments and it paid out 17 billion pesos in dividends.