Coming off a smashing, revenue-generating fourth quarter, American Movil (NYSE: AMX) CEO Daniel Hajj said on an earnings conference call that his company plans on spending up to $9 billion in 2012 to bring more data capacity to the growing number of smartphone users in Latin America. The company already boasted 242 million mobile subscribers at the end of 2011 and expects to add another 14 million this year.

"We are really focused on growth, and are going to try to capture new subscribers in Latin America," Hajj said.

American Movil revenues jumped 12.3% in the fourth quarter, beating analysts' expectations by 6%. In spite of that revenue growth, however, net profit fell 36% because of weakening of the peso. Quarterly postpaid subscribers increased by 1.6 million, raising the postpaid subscriber base by 20.5%, or 6.1 million for the year. The company also has 58 million wireline phone, Internet, and video subscribers.

Those postpaid subscribers are desirable, but they can result in a hit to profits because those long-term contracts come with the cost to the carrier of subsidizing expensive smartphones. That is the same paradox that affected U.S. carriers Verizon (NYSE: VZ), AT&T (NYSE: T), and Sprint Nextel (NYSE: S): The more smartphones  they sold -- especially iPhones -- the thinner their margins became.

I think Amercia Movil is a company worth watching. It is the dominant telecom in Mexico with a 70% market share, and is farsighted with its expansion plans. The company has managed to provide an excellent return on invested capital of over 20% from 2005 through 2010, and 14.5% for the trailing twelve months. Compare that to Verizon's average ROIC of 6.4%, AT&T's average of 7.2%, and Sprint's average of negative 10.6% during the same period.

As you can see from the chart below, the stock price has been on a down swing over the last year. Is it time to buy? I don't know but I am going to add it to your Watchlist. I am also going to give it a thumbs-up in CAPS.

Source: YCharts.

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