A mere three weeks ago, I extolled the virtues of what I considered the best international stock today: Latin American wireless operator America Movil (NYSE:AMX). As part of that analysis, I argued that "the company's aggressive deployment of next-generation high-speed networks and services leaves plenty of long-term opportunity ahead for high-margin revenues."

America Movil wasted little time moving in that high-speed direction, announcing recently that it has launched third-generation (3G) services in several major cities in its core market of Mexico, where it has 50 million subscribers. The network rollout starts with 15 major cities, with coverage in 350 cities planned by year's end.

America Movil's Mexican subsidiary Telcel has been testing network equipment from several vendors, such as Alcatel-Lucent (NYSE:ALU), Huawei, and Nokia (NYSE:NOK), but it recently awarded Sweden's Ericsson (NASDAQ:ERIC) an upgrade contract that will involve major cities such as Mexico City and Monterrey. 

Launching those high-speed services will allow America Movil to go after the high end of the mobile market -- users that will pay more for advanced services and features. Currently, the bulk of Latin American subscribers are on lower-cost prepaid cellular plans. America Movil has already proven it can deliver great results from even low-end subscriber growth, so the company should reap even greater profits from premium services.

America Movil is launching 3G services across its other Latin American units as well. In Columbia, its Comcel subsidiary recently launched next-generation services ahead of competitor Telefonica (NYSE:TEF). Just as operators Verizon Wireless -- a joint venture between Verizon Communications (NYSE:VZ) and Vodafone -- and AT&T (NYSE:T) have done in the U.S., America Movil has already launched 3G networks in Brazil, Argentina and Chile.

It's sometimes hard to believe, but America Movil is really just getting started. The 3G Americas organization reports that in the Latin American and the Caribbean markets, 17 operators with networks utilizing GSM technology have commercially launched 3G services in 10 countries. While this may sound like a lot, it only encompasses a paltry 50,000 subscribers utilizing 3G services today. That leaves an immense opportunity to woo hundreds of millions of subscribers over to the advanced services.

For those who thought America Movil's stock couldn't go any higher, some strong fundamental growth drivers will likely erase that doubt.

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