Capital utilization rate = position margin/client equity x 100%: some people use its reciprocal as an index to control risks, that is, client equity/position margin x 100%. In commodity futures, the fluctuation range is generally 4%-5%, the margin standard of exchanges is generally 5%-7%, and the margin standard of futures companies is generally 7%- 12%. Therefore, the margin level charged by a general exchange can withstand 1.4 stop-loss intervals, while the margin level charged by a futures company can generally withstand more than 2 stop-loss intervals. In order to keep pace with the spot market, the price limit of stock index futures reaches 10%, and the margin standard of 10% charged by the exchange can only bear a limit. According to the current market situation, it is predicted that the margin standard for futures companies to collect customers is generally at the level of 15%, and the limit is around 18%. If it exceeds 20%, it will be unattractive to speculative customers. By contrast, according to the exchange standard, the price limit that commodity futures can bear is 1.4 times that of stock index futures, and according to the margin standard of futures companies, the former is 1.6 times that of the latter. If calculated simply on average, the ability of commodity futures to withstand ups and downs is 1.5 times that of stock index futures. Therefore, if the capital utilization rate of commodity futures is lower than 50% as the safety critical line, the stock index futures should be around 30%.