Foreign companies listed on exchanges in the United State must comply with reporting requirements of the U.S. Securities and Exchange commission (SEC). All companies must file an annual report, Form 20F, within six months of the company's fiscal year end.
Initial public offerings are filed on Form F1, a registration statement and prospectus.
The SEC publishes a list of International Registered and Reporting Companies.
For more information about the SEC's rules for foreign issuers, read Accessing the U.S. Capital Markets:A Brief Overview for Foreign Private Issuers.
"The stocks of most foreign companies that trade in the U.S. markets are traded as American Depositary Receipts (ADRs). U.S. depositary banks issue these stocks. Each ADR represents one or more shares of foreign stock or a fraction of a share." (SEC)
Read "An Introduction to Depository Receipts" at the Investopedia website.