A Global Depository Receipt is a security which represents ownership in shares of a foreign corporation.
Investment banks in the United States and elsewhere purchase shares in foreign corporations and sell the equity in the form of a Global Depository Receipt, also called an International Depository Receipt, and formerly known as an American Depository Receipt.
They allow foreign companies to find investors in other countries, and vice versa, and the Americans and other foreigners can pay for the GDRs in American currency. They are typically sold in lots such that 1 GDR equals 10 shares of the underlying foreign company, but other ratios can be used.