Only before delivery can it be listed and circulated in the form of tickets.
For example, if you say that soybeans are now 8 yuan a catty, you can buy them as long as you sell them before the delivery date. As for whether the price you sell is high or low, it depends on your eyes. But if there is no next offer, you will have to deliver the goods. You will get a pile of soybeans, but you will be responsible for the transportation and storage afterwards. If the delivery is delayed, you will bear the corresponding losses.
This is the case that the US oil futures had a negative value before.
The delivery date is up, short selling, turn negative. At this point, there is actually a delivery option, so I will take oil. How's it going? But this subject is a bank and has no ability to transport oil. So it can only choose to pay the bill. But in any case, it is only an agent. In the end, it can pass on the loss to the ultimate investor by charging the agency fee itself. ......