Supply-demand ratio = supply/demand, that is, the ratio of supply to demand, less than 1, and demand is greater than supply. The ratio is greater than 1, and the supply exceeds demand. The smaller the proportion, the less competition. The greater the proportion, the greater the competition. The relationship between supply and demand refers to the relationship between supply and demand of commodities under the condition of commodity economy, and also reflects the relationship between production and consumption in the market. The relationship between supply and demand is the relationship between all products and services provided by society and social demand in a certain period of time. This relationship includes qualitative adaptation and quantitative balance.

1, the supply and demand index is abbreviated as CI, and the calculation formula is: CI= (number of rising varieties-number of falling varieties)/total. According to the formula, the range of CI is-1 to 1. 0 means the balance point between supply and demand. For example, the supply and demand index is greater than 0, which means that the supply is less than the demand, that is, the market is relatively large; And less than 0 means that supply and demand exceed demand, so the market is saturated, so it is not the bigger the better, but the smaller the better. BCI index is a commodity supply and demand index created by commercial companies and a qualitative index reflecting the economic trend of manufacturing industry. BCI index 0 is the balance point of supply and demand. When BCI is negative, it indicates that the manufacturing economy is shrinking; when BCI is positive, it indicates that the manufacturing economy is expanding. BCI is a monthly economic monitoring index, which is calculated by monitoring the monthly fluctuation of the most representative 100 basic raw materials in the eight major industries of the national economy.

2. The characteristics of the supply and demand index: First, the price fluctuates greatly. Only when commodity prices fluctuate greatly, traders who intend to avoid price risks need to use forward prices to determine prices first. For example, some commodities are subject to monopoly prices or planned prices, and the prices are basically unchanged. There is no need for commodity operators to use futures trading to avoid price risks or lock in costs. Second, the supply and demand are large. The function of the futures market is based on the extensive participation of both the supply and demand sides of commodities. Only goods with large spot supply and demand can fully compete in a wide range and form authoritative prices. Third, it is easy to classify and standardize. The quality standard of the delivered goods is stipulated in the futures contract in advance. Therefore, futures varieties must be commodities with stable quality, otherwise, it will be difficult to standardize. Fourth, it is convenient for storage and transportation. Commodity futures are generally long-term delivery commodities, which requires these commodities to be easy to store, not easy to deteriorate and convenient to transport, so as to ensure the smooth delivery of futures.