Emerging markets investors might want to look beyond China, India and Brazil to another top performer. This country ranks third in the world in exports. Last year, the dollar amount of goods sold outside its borders jumped 17% while the value of services rose 7%. Over the past year its shares gained 21%, versus 15% for the iShares MSCI Emerging Markets Index Fund (EEM) . Also, this country enjoys excellent contract law and accounting standards and a populace that's young, educated and productive.

The country (surprise) is the United States, and its companies have quickly become experts at cashing in overseas. Among the half of S&P 500 members that report their sales broken down by region, about half of those sales come from outside the U.S. Those with more overseas exposure are growing nicely, too. In a report issued early this month, Thomson Reuters forecasted 11% sales growth for S&P 500 companies with mostly foreign sales, versus 6% growth for those with mostly domestic sales.

There's no easy way to screen for U.S. companies with heavy sales exposure to emerging markets, because there's no standardized way for companies to report sales by geography. Investors who wish to search company-by-company should focus first on the industrial and materials sectors, which have seen particularly fast growth in foreign demand. Here are three candidates.

3M

Emerging markets contribution to sales: 33%

Conglomerate 3M (MMM) makes materials for just about every industry, including electronics, health care, mining and construction. Two-thirds of its sales come from outside the U.S., including one-third from emerging markets. Management says this percentage will increase to between 40% and 45% by 2015. Last year, the company increased its research-and-development spending with a focus on products with emerging market demand. Last quarter, companywide sales increased 10%, while sales in the Asia Pacific region jumped 22% and those in Latin America rose 12%. Shares of 3M sell for 15 times earnings and pay a 2.4% dividend.

Emerson Electric

Emerging markets contribution to sales: 34%

Emerson Electric (EMR) makes industrial components, electrical power systems, products to automate factories and more. The company turns nearly 17 cents of each sales dollar into operating profit, versus an average of 11 cents for industrial components makers. Rising prices for raw materials threaten to crimp profit margins, but management says it will launch a line of locally engineered products for sale in China and India with margins comparable to current products. The company's goal is to double its Asia sales to $10 billion by fiscal 2015, and to increase sales to all emerging markets to 45% of company sales. Shares have multiplied nearly sevenfold in price over the past 20 years and now sell for 18 times earnings. They carry a 2.2% dividend yield.

Caterpillar

Emerging markets contribution to sales (estimated): 25%

Caterpillar (CAT) reported 53% growth in machine sales and 6% growth in engine sales last year, as the world dug itself out of a construction slump and demand for mining equipment soared. Latin American sales jumped 68% and Asia Pacific sales rose 67%. Management plans to increase excavator production in China by 60% this year to meet demand. Caterpillar's purchase of Bucyrus (BUCY), a maker of mining machines, is expected to close in the middle of this year, and provides something of a hedge against inflation. The rising costs of metals make Caterpillar's machines more expensive to produce, but also send customers scrambling for machines to produce those metals. Shares sell for 17 times earnings and offer a 1.7% dividend.