The foreign exchange that buys RMB chooses USD, which has a higher hedging rate and less risk as a global currency. The foreign exchange quotation is based on the benchmark exchange rate of RMB/USD published by the People's Bank of China, and combined with the fluctuation of the international market, the foreign exchange banks calculate the central parity of RMB against freely convertible currencies such as Euro and Japanese Yen. Specifically, foreign exchange banks calculate the value according to the difference between the benchmark prices of the corresponding currency pairs. For example, the buying price is the value obtained by subtracting the spread from the benchmark price, while the selling price is the value obtained by adding the spread to the benchmark price.