Imagine it -- you learn of an intriguing company based in Elbonia. You want to invest in it, but it seems only to trade directly on the Elbonian stock market. Are you out of luck? Perhaps. But maybe not. There may be American Depositary Receipts (ADRs) available for the firm.

ADRs are securities representing shares of foreign firms. They were devised to help us Americans invest in such companies easily. Prices are quoted in U.S. dollars, and dividends arrive in dollar form. Whenever you see a familiar foreign company trading on the New York Stock Exchange or the Nasdaq, it's most likely actually its ADR that you see. (Sometimes you'll see the letters "ADR" next to a company's name when you call up a stock quote online.)

There are a lot of details to learn about ADRs. I'll offer just a few, but you can learn many more in this Rich Smith article: International Superstar Stocks: The ABCs of ADRs.

  • A single ADR share may or may not represent a single underlying share. The ratio varies and can be as high as several thousand foreign shares per ADR share, or even a fraction of a foreign share per ADR. It's good to find out exactly what you're getting when you buy an ADR.
  • There are levels of ADRs. Level I is the lowest, with the least stringent requirements, and these ADRs trade only over the counter. Level II and III ADRs can be found on the New York Stock Exchange, the American Stock Exchange, or the Nasdaq.
  • You can buy most ADRs through your regular brokerage. Just remember that they carry risks, as any American stock does -- and they actually carry additional risks as they are tied to the local country's economic and political stability.

At, I found a list of top ADRs by value. Here are a few of the best-known ones, to give you an idea of what's out there:

  • Nokia (NYSE:NOK), a Finnish telecommunications company
  • Arcelor Mittal (NYSE:MT), a Netherlands-based steel company
  • Petroleo Brasileiro (NYSE:PBR), a.k.a. Petrobras, a Brazilian oil company
  • America Movil (NYSE:AMX), a Mexican wireless telephone company
  • Baidu (NASDAQ:BIDU), a Chinese Internet search company
  • BP (NYSE:BP), a U.K.-based oil company
  • Taiwan Semiconductor (NYSE:TSM), a (duh) Taiwanese semiconductor company   
  • GlaxoSmithKline (NYSE:GSK), a U.K.-based pharmaceutical company

If you're interested in investing internationally, let me point you to some of the most promising and exciting foreign companies we've found at the Fool. You can test-drive (for free) our new Global Gains newsletter for recommended foreign investments. A free trial will give you full access to all past issues, so you can read in detail about every recommendation.

Longtime Fool contributor Selena Maranjian does not own shares of any companies mentioned in this article. GlaxoSmithKline is a Motley Fool Income Investor recommendation. is a Rule Breakers recommendation. Try any one of our investing services free for 30 days. The Motley Fool is Fools writing for Fools.