The difference between A50 and SSE 50 is that:
The constituent stocks are not exactly the same: the constituent stocks of A50 are selected from Shanghai and Shenzhen stock markets, including the 50 companies with the largest market value in China A-share market; 50% of the shares of the Shanghai Stock Exchange are limited to the Shanghai Stock Exchange.
The exchanges are different: A50 and related stock index futures are listed on Singapore Stock Exchange, and SSE 50 Index is listed on Shanghai Stock Exchange.
Trading time is different: A50 stock index futures trading time is 9: 00- 16: 30, 17: 00-5: 15, and SSE 50 stock index futures trading time is 9: 30-1:00.
SSE 50, the investment index, is a scientific and objective method to select 50 representative stocks with large scale and good liquidity in Shanghai stock market to form sample stocks, thus fully reflecting the overall situation of a group of leading enterprises with the most market influence in Shanghai stock market.
SSE 50 Index was officially released on June 5438+1October 2, 2004. Its goal is to establish an active and large-scale investment index, which is mainly used as the basis of derivative financial instruments.
Compilation method: compiled by Shanghai Stock Exchange.
sample
Sample space: SSE 180 index sample stocks.
Sample size: 50 stocks.
Sampling standard: scale; Liquidity of assets
Sample selection method: the stocks are comprehensively sorted according to the total market value and transaction amount, and the top 50 stocks are taken as samples, except those stocks with abnormal market performance that are determined by the expert committee to be unsuitable as samples.
Exponential calculation
The SSE 50 Index adopts the dividend weighting method and is weighted according to the adjusted share capital of sample stocks. The calculation formula is:
Index of reporting period = adjusted market value of constituent stocks during reporting period/base period * 1000.
Among them, the adjusted market value = σ (market price × adjusted number of shares).
Exponential correction
(A) the revised formula
The SSE 50 index is revised by "divisor correction method".
When the list of constituent stocks changes, the share capital structure of constituent stocks changes, or the adjusted market value of constituent stocks changes due to non-trading factors, the original fixed divisor is corrected by "divisor correction method" to ensure the continuity of the index. The modified formula is:
Adjusted market value before correction/original divisor = adjusted market value after correction/new divisor
Among them, the adjusted market value after correction = the adjusted market value before correction+the new (minus) adjusted market value; From this formula, a new divisor (that is, a modified divisor, also known as a new base period) is obtained, and the future index is calculated accordingly.
(two) the situation that needs to be corrected
(1) ex-dividend-where the constituent stocks have ex-dividend (dividend distribution), the index will not be revised, and it will naturally fall.
(2) Ex-dividend-for constituent stocks that have been sent or allotted shares, the index shall be revised before the ex-dividend benchmark date of constituent stocks.
Adjusted market value after correction = ex-dividend quotation × ex-dividend shares+adjusted market value before correction (excluding ex-dividend shares);
(3) Suspension-when the constituent stocks are suspended, the final transaction price is taken to calculate the index until the resumption of trading.
(4) Delisting-If the constituent stocks are delisted (the transaction is terminated), the index shall be revised before the delisting date.
(5) Changes in share capital-in the case of other changes in the share capital of constituent stocks (such as the issuance of new shares, the listing of rights issues, the listing of internal staff shares, etc.), the circulating share capital will increase. ), the index should be revised before the change of constituent share capital.
(6) suspension-when some sample stocks are suspended, the index will be calculated as usual; When all sample stocks close, the index stops counting.