Symmetry of Single Exchange Rate "Compound Exchange Rate" A government only stipulates one exchange rate for the exchange of its own currency with another country's currency. In countries with a single exchange rate, trade and non-trade foreign exchange receipts and payments are settled at one exchange rate.

The compound exchange rate is also called "multiple exchange rate". Symmetry of "Single Exchange Rate" Under foreign exchange control, a country sets different exchange rates for the same foreign currency for different purposes. The main purposes of setting up a composite exchange rate are: (1) encouraging or restricting the export of certain commodities; (2) encouraging or restricting the import of certain commodities; (3) Encourage some commodities to be produced in China; (4) selling at a high price or buying at a low price to enrich the state treasury. For example, in 1930s, Germany gave a more favorable exchange rate to the import of war preparation materials, and other commodities were exchanged at a higher exchange rate.