First of all, stock index futures is a leveraged trading tool, and its own trading characteristics determine that when the market falls, investors often choose to sell empty orders to bet. This bet means that the market falls, and if the market does fall, investors can make a profit by shorting futures. Therefore, when there is a downward trend in the market, investors will hedge their risks by short selling stock index futures, which leads to the phenomenon of stock index futures helping to fall.

Secondly, as a derivative, stock index futures are usually related to the physical market. In other words, changes in stock index futures prices will have an impact on the physical market, especially when the market falls. When investors see the decline of stock index futures, they often think that the physical market will also have a downward trend, so they will avoid risks by selling physical assets such as stocks, thus aggravating the decline of the market.

Finally, market sentiment is also one of the factors that affect the decline of stock index futures. When the market falls sharply, investors are generally depressed and lose confidence and patience. At this time, investors are more inclined to speculate in the short term and chase short-term bands, so a large amount of funds flow to the stock index futures market, which makes its price drop more obvious and indirectly helps the decline of the physical market.