The middle price of ruble is the middle price of exchange rate. The central parity of exchange rate is the reference price of currency to currency. After the close of each working day, the closing price of USD against RMB and other trading currencies in the foreign exchange market of the bank on that day is the middle price of the currency against RMB on the next working day. The central parity of exchange rate = (spot exchange rate buying price and selling price) /2. It is the most important reference index of inter-bank spot exchange rate. For example, the calculated prices of RMB against Euro, Japanese Yen, Hong Kong Dollar, British Pound, Australian Dollar and New Zealand Dollar are all intermediate prices.

Seven key factors affecting foreign exchange rate:

1. Inflation rate Changes in market inflation lead to changes in the currency exchange rate. Countries whose inflation rate is lower than that of another country will see their currencies appreciate. In the case of low inflation rate, the prices of goods and services rise slowly. The currency value of countries with persistently low inflation rate increases, while the currency of countries with high inflation rate usually depreciates, which is usually accompanied by higher interest rates.

2. Interest rate. Changes in interest rates will affect the value of the currency and the exchange rate of the US dollar. Exchange rate, interest rate and inflation are all related. Rising interest rates will lead to the appreciation of a country's currency, because higher interest rates will provide lenders with higher interest rates, thus attracting more foreign investment, which will lead to an increase in the exchange rate.

3. Balance of payments. A country's current account reflects the balance between trade and foreign investment income. It consists of the total number of transactions, including exports, imports, debts, etc. Because more money is spent on imported products than income from export sales, the current account deficit leads to depreciation. The balance of payments makes the exchange rate of the domestic currency fluctuate.

4. Government debt. Government debt is public debt or national debt owned by the central government. It is impossible for a country with government debt to obtain foreign capital, which will lead to inflation. If the market predicts a country's government debt, foreign investors will sell their bonds in the open market. As a result, its exchange rate will fall accordingly.

5. Trade terms. The terms of trade related to current account and balance of payments are the ratio of export price to import price. If a country's export price rises faster than its import price, its terms of trade will improve. This leads to higher income, which in turn leads to higher demand for the country's currency and an increase in its value. This led to the appreciation of the exchange rate.

6. Political stability and performance. A country's political situation and economic performance will affect its monetary strength. A country with less risk of political turmoil is more attractive to foreign investors, so it will attract investment from other countries with more stable politics and economy. In turn, the increase of foreign capital leads to the appreciation of the domestic currency. A country with sound financial and trade policies will not provide any room for the uncertainty of its currency value. However, a country prone to political chaos may see the exchange rate depreciate.

7. Economic recession. When a country experiences a recession, its interest rate may fall, thus reducing its chances of obtaining foreign investment. As a result, compared with the currencies of other countries, their currencies depreciated, thus lowering the exchange rate.