Derivative financial instruments that use margin trading to make physical delivery at the current price in a certain period of time in the future.

For example, the closing price of indica rice 1 109 on Friday was 2604, that is, the indica rice delivered in September this year was purchased at the price of 2604 yuan/ton. 1 indica rice contract is 10 ton, so the commodity value corresponding to 1 indica rice 1 109 contract is 26040 yuan. But you don't have to pay all 26,040 yuan, but you can buy the 1 hand indica rice contract by paying 26,040 *12% = 3124.8 yuan according to the agreed margin ratio.

If the contract of indica rice 1 109 rises from 2,604 to 2,700 in the future (an increase of 3.7%), then you can earn (2,700-2,604) */kloc-by paying the deposit of 3 1 24.8 yuan more than the contract. This is the leverage effect of futures. Of course, the increase in handling fees or the margin ratio of futures companies is not considered.

Futures adopt T+0 trading mode, so you can make more short positions.

I suggest you read it: Technical Analysis of Futures Market, translated by Ding Shengyuan and translated by john murphy.