Additional margin, you can continue to buy next month's contract, but it is not recommended to hold stock index futures for a long time. Because the money earned by one person is the money lost by another person, this market will never create new wealth, so the so-called investment will lose its meaning.

In the traditional futures market, there are only two types of participants-speculators and hedgers. Hedgers give profits to speculators to hedge spot risks; Speculators connect buyers and sellers, making the market more active and making price information more effective. The cooperation between the two types of participants makes the futures market have the functions of "price discovery" and "hedging".

However, with a large number of "investment" funds joining the ranks of speculators, the strength of the two types of participants in the futures market is unbalanced. Facing the rules of zero-sum game in futures trading, the profit expectation and profit scale of speculators are getting bigger and bigger after the scale of speculators continues to expand; The profits from these funds represent the losses of the hedgers. When the hedger can't "pay" the speculators' profits, the hedger has to quit.

Therefore, long-term holding is not recommended.