Last year, Wynn Resorts CEO Steve Wynn was spending two hours each day on Chinese lessons. At age 65, Wynn is worth $3.9 billion -- yet he's still learning new tricks.

Why? Because the Wynn Macau -- Mr. Wynn's latest megacasino -- was getting set to open just off the coast of China. That's right on the doorstep of some three billion potential customers.

Big bets for big paydays
How has the Wynn Macau fared? Analysts see it tracking above previous estimates, and contributing some $300 million in EBITDA in 2007.

But Steve Wynn isn't the only billionaire going gaga over foreign markets. Wynn rival and Las Vegas Sands CEO Sheldon Adelson, himself worth $28 billion, is making a similar investment in Macau's potential. Then there's the large number of companies, from Carbo Ceramics (NYSE:CRR) to United Parcel Service (NYSE:UPS) to Wrigley (NYSE:WWY) to PepsiCo (NYSE:PEP), whose recent earnings reports showed strong overseas growth. As economist Joseph Carson told The Wall Street Journal recently, "The international influence on firms' profits has never been so strong."

Entrepreneurs and investors alike
Meanwhile, there are the master investors who have been buying up foreign stocks at a rapid clip. Jean-Marie Eveillard continues to hold Fuji (NASDAQ:FUJI), while Mark Hillman is still picking up shares of Tata Motors (NYSE:TTM).

Even Warren Buffett stoked the international frenzy early in 2006 with purchases of PetroChina (now sold) and Israel's Iscar Metalworking.

The question we need to ask
So -- and you had to know I was coming around to this -- what have you been adding to your portfolio lately?

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This article was originally published on Jan. 19, 2007. It has been updated.

Tim Hanson owns shares of Wynn Resorts. Wrigley and UPS are an Income Investor selections. No Fool is too cool for disclosure.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.