1, stock index futures (SPIF), full name of stock index futures, also known as stock index futures and futures index, refers to standardized futures contracts with stock index as the subject matter. The two sides agreed that on a specific date in the future, the underlying index can be bought and sold according to the size of the stock price index determined in advance, and the difference will be settled in cash after the expiration. As a type of futures trading, stock index futures trading has basically the same characteristics and processes as ordinary commodity futures trading. Stock index futures are a kind of futures, which can be roughly divided into two categories, commodity futures and financial futures.

2. The transaction price of entrusted selling is transferred to the "outer disk"; Entrust the transaction into the "inner disk" at the purchase price.

The external market is also called active buying, that is, the accumulated trading volume at the selling price; Internal selling is also called active selling, that is, the cumulative trading volume at the purchase price. The outer disk reflects the willingness to buy actively, and the inner disk reflects the willingness to sell actively.

Inner disk: buy one, buy two, buy three price transactions, and add the statistics of the number of buy transactions to the inner disk.

Outer disk: a transaction that is concluded at the price of selling one, selling two and selling three. Sales statistics are added to the external disk. The two data of inner disk and outer disk can be used to judge the strength of buying and selling rights. If the number of external disks is greater than the number of internal disks, the buyer is stronger; If the number of inner disks is greater than the number of outer disks, the strength of the seller will be stronger.