Returns on international stocks have pounded those of their domestic counterparts over the past several years. Generally, you can count on dumb money to follow those returns, especially after a long period of outperformance. Yet when some of the best-performing mutual fund managers in the country start following the crowd, it's worth taking a second look.

Bloomberg recently reported that several top-performing fund-management firms in the global asset-allocation category, including BlackRock, Goldman Sachs (NYSE:GS), and Waddell & Reed (NYSE:WDR), have unusually low percentages of their fund holdings in U.S. stocks. Goldman's Growth Strategy Portfolio (GAPAX) has increased its international allocation from 32% to 40% since the beginning of the year. Waddell's Asset Strategy Fund (UNASX) has hiked its foreign exposure to a full half of its holdings, up from 32% this time last year. And BlackRock's Global Allocation Fund (MDLOX) has just 21% of its holdings in U.S. stock.

Risky business?
Most investors perceive international investing as riskier than putting their money in domestic stock markets. Even though economic growth in the U.S. has slowed significantly in recent quarters, investors who choose domestic companies can count on higher levels of disclosure and regulation than they'll find in many other countries, especially among emerging markets such as those of Brazil, Russia, India, and China. In addition, many large American companies, including ExxonMobil (NYSE:XOM) and Altria (NYSE:MO), earn a large fraction of their revenues from international operations. You don't have to go beyond the borders of the S&P 500 to get a lot of international exposure.

Yet macroeconomic factors are pushing investors away from American shores. The falling dollar, which recently hit all-time lows against the euro and breached the $2 mark against the British pound, has made some foreign investors leery of currency losses that have resulted from investing in the United States. In addition, better economic growth prospects in Europe and the emerging markets make their stocks more attractive than U.S. stocks. Funds are even starting to get back into larger Asian markets such as Japan and Singapore; the average global asset-allocation fund has doubled its exposure to Asia over the past five years.

Where the money is
If you're content with average returns, then staying inside the U.S. for your investments should give you reasonable results over the long haul. But to find the best opportunities for fast-paced growth, you have to look around the world. Bill Mann, who runs the Fool's Global Gains international-investing service, recently highlighted the value of investing in Taiwan, which has much of the exciting economic prospects of China without all the hype and political risk. He has also pointed out the value of diversifying your portfolio by buying stocks with international currency exposure, as a hedge against the risk that the dollar will continue to decline.

From a financial-planning perspective, putting some international investments in your portfolio helps to increase your potential for growth while also leaving you less dependent on the continuing success of the American economy. Yet as the 9% drop in the Shanghai markets in early February shows, these markets aren't for the meek. Although past periods of similar outperformance have often been followed by abrupt corrections and longer declines in international markets, long-term investors can afford to ride out the bumps in the road to reap higher returns.

As the economy becomes more global in scope, investors are following suit. Despite several consecutive years of strong performance, fund managers are showing that the heyday of international stocks isn't over yet.

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Fool contributor Dan Caplinger has been focusing on international stocks in his portfolio for several years. He owns shares of Altria. The Fool's disclosure policy follows you around the world.