1, calculated at the transaction price at the opening, calculated at the latest price (change) after the closing, and calculated at the settlement price at the settlement of the day.

2. Exchanges only settle accounts with futures companies, and futures companies settle accounts with customers. Therefore, you have to obey the rules of the futures company on how to calculate the margin. The margin of the futures company is at least three percentage points higher than that of the exchange (as stipulated by the CSRC), so there is no need to care too much about which price to calculate the margin.