This "spread" is also assessed when investors trade foreign currencies through a brokerage firm.

WSJ: Questions to Ask Your Financial Adviser About Fees

To qualify for liberation from U.S. paper shufflers a foreign firm must establish that its shares mostly trade overseas.

FORBES: These Stocks Sidestep Sarbanes-Oxley Idiocies

Foreign securities are another option, but investors can buy them only through a securities firm, and the Foreign Exchange and Foreign Trade Control Act still puts obstacles in their way.

ECONOMIST: Not all it should be

Looked at through the lens of cross-border trade between an American firm suffering devaluationist policies and a foreign importer buying American goods with a rising currency, ultimately the importer is going to have to sell goods back to Americans in order to continue importing.

FORBES: The sheer folly of currency devaluation.

And it counts any firm with over 25% foreign ownership as an outside buyer, forcing the government to track every trade in the shares of public companies near the limit.

ECONOMIST: Protectionism in Argentina