Source: American Tower.

Shares of American Tower Corp (AMT -0.11%) have been on a tear in 2014. The stock has gained 26% year-to-date compared to just 11% for the S&P 500 index -- and it still has room to run. Here are the three biggest reasons why American Tower shares could continue to rise in the new year.

Top dog in a vital industry
There's no denying that cell towers are here to stay. The wireless industry may change over and over again, but the thirst for mobile voice and data communications should only continue to grow and evolve into new formats.

That said, investors with an interest in the mobile tower space only have a handful of options. American Tower competes against Crown Castle International (CCI -0.97%) and SBA Communications (SBAC 0.59%), and there is no question of who leads the pack.

Not only is American Tower about the size of its two chief rivals combined, but the leading company also runs its business with unmatched efficiency.

At the moment, American Tower's trailing-12-month operating margin sits at 38%, far ahead of Crown Castle and SBA at 29% and 24%, respectively. The story doesn't change if you prefer looking at net income or cash flows, as American Tower bests its rivals in nearly every category.

So American Tower is a clear-cut leader in an industry that isn't going away anytime soon. That's a mighty fine starting point for curious investors.

High growth, low risk
This sounds impossible, but it's true. American Tower really does deliver both strong growth and limited operating risk.

You've already seen the growth. American Tower's quarterly sales are on an annual run rate of 29% growth, while earnings are increasing by 15%. These numbers are impressive for even the hottest growth stocks.

Meanwhile, the cell tower business model lends itself to extremely stable, long-term results. American Tower's customers lease tower access in multi-year deals, shielding the tower operator from temporary downturns. Over 70% of the company's contracts have more than five years remaining on their lease schedules.

Source: American Tower

The international shopping spree
Finally, American Tower belies its all-American name by making significant investments overseas. Last month alone, the company announced two tower network buyouts in Brazil and Nigeria amounting to $2.3 billion -- the acquisitions will boost the company's global tower count by 11,000 sites, or nearly 16%.

Admittedly, the competition is not sitting still. Crown Castle acquired nearly 17,000 tower sites of its own over the last three years. But Crown Castle's acquisitions were based on the increasingly mature American market while American Tower focuses on growth avenues in developing markets.

For perspective, the Brazilian gross national income has soared 80% over the last decade while Nigeria's economy tripled in size. Meanwhile, the U.S. saw growth of only 31% over the same period.


Source: American Tower

American Tower has only just begun to establish itself in fantastic new locations around the globe. The long-term growth ceiling is nowhere in sight, and I'm excited by American Tower's willingness to pursue these opportunities in emerging markets.