In today's world, most companies span several regions and sell across the world. As Foolish colleague Morgan Housel notes, 10 years ago, less than a third of S&P 500 revenue growth came from abroad. Today, that area makes up half of the S&P 500's growth.

And that number is growing. The truth is, investors regularly underestimate how much demand comes from abroad. More importantly, for large, multinational corporations that have already established a presence in their home markets, much of their future growth comes from abroad.

With that in mind, today we're looking at Western Union (NYSE: WU). We'll examine not only where its sales and earnings come from, but how its sales abroad have changed over time.

Where Western Union's sales were five years ago
Five years ago, Western Union was already an established global payments company and received 63% of its sales from international markets.

Source: S&P Capital IQ.

Where Western Union's sales are today
Today, the trend toward international sales driving Western Union's results keeps growing.

Source: S&P Capital IQ.

It's not that international sales are just growing; they're also picking up the slack while United States sales shrink.

Segment

5-Year Sales Growth

United States

-17%

International

52%

The great part for Western Union investors is that the company has doggedly pursued its international opportunity in recent years. It recently announced a deal to offer transfer services across a large Russian bank with 9,000 locations. Not only that, but after a long effort to expand its presence, Western Union is now available in 30,000 ATM locations throughout Europe and Asia in addition to its 470,000 Agent locations.

But payments and money transfer services is a booming area of finance that Western Union occupies just one niche of. How does the company stack up against some other investing options in the space? If investors are looking for a company seeing great growth not just internationally, but in the United States as well, Visa (NYSE: V) comes to mind. The company's U.S. segment has jumped 40% in the past three years while its "rest of world" segment has soared 62%!

Another option could be American Express (NYSE: AXP). The company's growth trails Visa's by a wide margin, and it's far more dependent on the United States on a percentage of revenues; 71% of sales come from the United States. Still, American Express has a large, established presence overseas that could become a key advantage in coming years.

In the end, if you're an investor looking for international opportunity, Western Union seems to be executing extremely well. However, that shouldn't stop you from checking out other plays in the payments space, as a number of companies have built up global networks that should see outsize growth as the global economy keeps chugging in the years ahead.

Keep searching for global opportunities
There's a reason companies are seeing outsize growth around the world; in the past decade, emerging market consumer spending grew 250%, leaving the growth rates of the U.S. and Europe in the dust. If you're an investor scanning the world for opportunities, look no further than our new report "3 Companies Set to Dominate the World." In it, Fool analysts select three companies that have an international growth opportunity that's simply stunning. The report is free, but it won't be available forever, so get your copy by clicking here today!