Illustration/Su Yi reader Mr. Wang wrote to ask: "What is margin, what is the futures margin now, and what is the impact of high or low margin?" A: The so-called deposit, in layman's terms, is the deposit. For example, when buying a house, the buyer needs to pay the deposit in advance and pay the full amount after the formal transaction. When purchasing a futures contract, you still need to pay a deposit, but at this time it was renamed as "deposit" as a guarantee for the performance of the futures contract. 1865, the Chicago Board of Trade introduced standardized contracts, and at the same time implemented a margin system, charging both parties with a margin not exceeding 10% of the contract value, marking the birth of real futures trading. Margin in a broad sense includes settlement margin and trading margin. Generally, the settlement deposit is paid by the member units to the exchange according to a fixed standard, which is a fund prepared in advance for transaction settlement. Trading margin refers to the actual deposit paid by member units or customers for holding futures contracts in futures trading. Different varieties, the deposit collection ratio is also different. At present, the margin collection ratio of various futures products in the domestic futures market is generally 5%~ 10% of the contract value. The margin collection ratio is not static, and the different stages of futures contract listing operation, the size of contract positions and the trend of contract prices will all have an impact on the margin ratio. In addition, futures companies opened by investors will also increase a certain proportion on the basis of the exchange margin to control risks. In the process of holding positions, investors will have floating profits and losses (the difference between the settlement price and the transaction price) due to the constant changes of market conditions, so the funds actually available for making up losses and providing guarantees in the margin account will increase or decrease at any time. Floating profit will increase the balance of margin account, while floating loss will decrease the balance of margin account. The minimum balance that must be kept in the margin account is called maintenance margin. When the book balance of the margin is lower than the maintenance margin, the trader must make up the margin within the specified time, otherwise the exchange or institution has the right to carry out compulsory liquidation on the next trading day. This part of the margin that needs to be replenished is called additional margin. The advantage of margin trading is that the cost of leveraged trading is reduced and the profit is enlarged. However, benefits always equal risks. Investors should remember to control their positions, otherwise they will face the risk of additional margin or even short positions. At present, the minimum margin collection ratio of futures products of the three major domestic futures exchanges: Shanghai Futures Exchange: copper, 5%; Aluminum, 5%; Zinc, 5%; Gold, 7%; Fuel oil, 8%; Rubber, 5%. Variety of Dalian Commodity Exchange: soybean, 5%; Soybean meal 5%; Soybean oil 5%; Corn, 5%, palm oil, 5%; Polyethylene, 5%. Zhengzhou Commodity Exchange: rapeseed oil, 5%; PTA，6%； Cotton, 7%; White sugar, 6%; Wheat, 5%. (Readers' investment questions can be sent to cbnmoney@yahoo.