According to the provisions of the Ministry of Finance, financial enterprises with foreign exchange business (including banks, insurance companies, securities companies, trust and investment companies, futures companies, fund management companies, leasing companies, finance companies, etc.). ) you can use the accounting method of separate foreign exchange account system or the accounting method of unified foreign exchange account system. At present, China's securities companies, commercial banks and corporate finance companies generally adopt the foreign exchange ledger system for foreign exchange business accounting. Under the foreign exchange accounting system, various foreign currency businesses fill in accounting vouchers, register accounting books and prepare statements in the original currency. For businesses involving different currencies, a transitional account (such as "currency exchange" or "foreign exchange") is set up, and the exchange of various currencies and the contact between accounts are carried out through this transitional account. At the end of the accounting period, the balances of foreign currency accounts and the above-mentioned transitional subjects are converted into functional currency according to the exchange rate at the end of the accounting period stipulated by the state, and the balances of "currency exchange" or "foreign exchange" due to exchange rate changes are converted into exchange gains and losses and included in the current profits and losses. In practice, only large currencies such as US dollars and Hong Kong dollars are accounted for separately. Some small currencies, such as Thai baht, are not reflected in another account book, but enter a large currency account as foreign currency. Therefore, in addition to RMB account books, financial enterprises also need to set up different account books in major foreign exchange currencies for accounting and preparation of accounting statements. All account books must be accounted for in accordance with the Accounting System for Financial Enterprises. These different account books are independent of each other. In this book, we mainly analyze two modes of foreign currency accounting system: securities companies and financial companies.