I. Introduction to the Shanghai and Shenzhen 300 Index \ x0d \ x0d \ The Shanghai and Shenzhen 300 Index is the first index jointly released by the Shanghai and Shenzhen Stock Exchanges to reflect the overall trend of the A-share market. The sample of the Shanghai and Shenzhen 300 Index covers about 60% of the market value of the Shanghai and Shenzhen markets, which has a good market representation. At present, among the 300 sample stocks, 92 sample stocks from Shenzhen Stock Exchange 12 1 00 and Shanghai Stock Exchange 14 1 80 are from Shanghai Stock Exchange 180, with the selection rates of 92% and 78. 5% respectively. \ x0d \ x0d \ covers leading enterprises in dozens of industries, such as banking, steel, petroleum, electric power, coal, cement, household appliances, machinery, textiles, food, brewing, chemical fiber, non-ferrous metals, transportation, electronic devices, commercial department stores, biopharmaceuticals, hotel tourism and real estate. \ x0d \ x0d \ Shanghai and Shenzhen 300 Index takes 65438+February 3, 20041day as the base date and the adjusted market value of 300 constituent stocks as the base period, and the base period index is set at 1000 points, which has been officially released since April 8, 2005. \x0d\ \x0d\ is calculated according to the following formula: reporting period index = adjusted market value of constituent stocks in the reporting period/adjusted market value of constituent stocks on the base date × 1000\x0d\ \x0d\ where the adjusted market value = ∑ (market price × adjusted share capital), and the adjusted market value of constituent stocks on the base date is also called divisor. The classification and filing methods of CSI 300 are shown in the following table. For example, if the proportion of tradable shares (circulating share capital/total share capital) of a stock is 7% and less than 10%, the circulating share capital will be the weight; The circulation ratio of a stock is 35%, which falls within the interval (30, 40), and the corresponding weighting ratio is 40%, so 40% of the total share capital is used as the weight. \ x0d \ x0d \ circulation ratio (%) \ x0d \ ≤140)\ x0d \ (10,20) \ x0d \ (20,30) \ x0d \ (30,40) \ x0d. 80 \ x0d \ x0d \ weighted proportion (%)\x0d\ circulation proportion \ x0d \ 20 \ x0d \ 30 \ x0d \ 40 \ x0d \ 50 \ x0d \ 60 \ x0d \ 70 \ x0d \ 80CSI 300 \ x0d \ x0d \ Shanghai and Shenzhen 300 Index shall be adjusted once every six months according to the principle of combining sample stability with dynamic tracking, and the adjustment ratio shall generally not exceed 10%. Sample adjustment sets the buffer, and the new samples ranked within 240 will enter first, and the old samples ranked before 360 will be reserved first. When a sample stock company withdraws from the market, it will be removed from the index sample from the delisting date and replaced by the stock with the highest ranking among the candidate samples in the latest periodic adjustment of the index.