It is scheduled to avoid month-end fluctuations on the third Friday of each month.
According to the provisions of the Shanghai and Shenzhen 300 stock index futures contract (draft for comment), the last trading day and delivery date are "the third Friday of the contract expiration month, which will be postponed in case of national legal holidays". According to the calculation, the third Friday of each month is basically in the middle of the month, and sometimes it will even be delivered on 14 and 15 of the month. This is different from the fact that foreign stock index futures are usually delivered at the end of the month.
According to insiders, the stock market usually has a "month-end effect", and many legal entities will go to day trading for accounting reasons, so the month-end fluctuation will be even greater. Stock index futures also have a "maturity effect", and many foundations close their positions on the maturity date, which leads to price fluctuations. If the volatility of the two markets is superimposed, it will increase the volatility of the market and have a greater impact on both the spot market and the futures market. Now the delivery date is set on the third Friday, which can basically be delivered in the middle of the month to avoid violent market fluctuations at the end of the month.