It's no surprise that international stocks have gained popularity with investors over the past few years. They've generated absolutely amazing growth.

For the past six years in a row, the Vanguard Total International Stock Market Index outpaced the Vanguard Total Stock Market Index. The latter tracks just the broad U.S. market, including top holdings in Pfizer and Verizon.

Even though foreign markets probably won't outperform U.S. markets every year, international stocks are undeniably worth your time to research. And thanks to American depositary receipts (ADRs), U.S. investors have more opportunities than ever to trade foreign securities on domestic exchanges.

This month's best performances
Foreign companies that participate in an ADR program must file reports in accordance with U.S. regulations, but their different corporate cultures and business decisions can seem unorthodox to American investors.

To help us understand this month's top-performing ADRs, we'll tap the expertise of the more than 110,000 investors participating in Motley Fool CAPS, the Fool's free investing community. Here are the top four performers over the past month among ADRs, along with their ratings from the CAPS community.



% Change

CAPS Rating
(out of 5)

Chemical & Mining Co. of Chile (NYSE:SQM)




Agria Corp. (NYSE:GRO)




China Medical Technologies (NASDAQ:CMED)








Data provided by Capital IQ, a division of Standard & Poor's, and Motley Fool CAPS as of June 23; screen excludes companies with market caps of less than $100 million.

Remember, I chose these stocks as jumping-off points for further research, not as formal recommendations. That said, checking out stocks with CAPS' four- and five-star ratings is an effective tool for investors.

Why they rallied
Chemical & Mining Co. of Chile: As the saying goes, "A rising tide lifts all boats," and the agriculture tide has been rising rapidly. Over the past month, competitors like Potash Corp. of Saskatchewan (NYSE:POT) and Agrium (NYSE:AGU) have had nice runs, but SQM's month has been more of a sprint. SQM enjoys nearly unanimous support (435 of 443) from CAPS All-Stars who have chimed in, and has been a five-star stock since April 2007 -- it's since gained more than 200%.

Agria: Another agriculture stock getting a boost from secular trends. Since it went public in November, Agria shares have actually plunged 47%, stemming partly from the Chinese market crash and some questionable ethics. CAPS investors seem to have shaken off the bad news and recently raised the company's rating from three stars to four stars

China Medical: Last February, doctor by day/CAPS All-Star by night DrQuack gave CMED the thumbs-up, noting: "As a physician- I am very excited about this new technology [non-invasive diagnostic technology], and I think this company has the best chance of being a worldwide leading distributor of it. American companies just cant compete with chinese production pricing." CMED shares have risen nearly 90% since his pick was made.

ILOG: In shaky economic times, companies seek to reduce costs and become more efficient. ILOG's enterprise business software helps companies do just that. A few weeks back, the company released its latest versions of supply chain, inventory, and product flow analysis and optimization software. The stock has unanimous CAPS All-Star approval, but could use more ratings, which you can add by clicking here.

What do you think?
Read what other investors have to say about these stocks, and then make your voice heard on Motley Fool CAPS. It's 100% free, so sign up today!