What is a set bidding? What are the steps for collective bidding?

Understanding the principles of collective bidding is beneficial to stock trading and stock speculation.

In each trading day, the auction of any securities is divided into two parts: collective bidding and continuous bidding. Collective bidding refers to the centralized processing of all valid commissions, the auction time for Shenzhen and Shanghai cities is from AM to AM on the trading day. The auction is completed in four steps:
Step 1: Determine the valid commission when there is a limit on the rise and fall, the valid Commission is determined as follows: the maximum price and minimum price for the current day are calculated based on the closing price of the previous trading day of the securities and the determined increase or decrease. The valid price range is all the prices between the maximum price and the minimum price of the securities. The delegated price exceeding this range is invalid, and the system automatically removes the order.
Step 2: select the transaction price. First, select the maximum transaction volume price for all delegates within the valid price range. If there are more than two such prices, select the price based on the following rules:
(1) All purchase commissions higher than the selected price and all sales commissions lower than the selected price can be fully sold.
(2) All parties entrusted with the same price must deal with the deal. If there are more than one price that meets the above conditions, select the price closest to the primary market price.
Step 3: centrally merge all purchase orders in the order of the delegated price limit from high to low, and the price limit is sorted in sequence according to the time when they enter the system; all sales commissions are arranged in the order of delegated price ranges from low to high, and the price options are sorted in sequence according to the time when they enter the system. The purchase commission and the sales commission are matched one by one in sequence, that is, the transactions are made in order of "price first, time first at the same price" until the transaction conditions are not met, that is, there is no selling commission whose price is higher than or equal to the transaction price, or where the price is lower than or equal to the transaction price. All transactions are made at the same price.
Step 4: reveal the market
(1) If the transaction volume of the securities is zero, the transaction price position will be revealed as the opening price, recent transaction price, highest price, lowest price, and reveal the transaction volume and transaction amount.
(2) In the remaining valid commission, the actual maximum price is the price to be revealed. If the maximum price does not exist, the price to be revealed is empty; the actual minimum selling price is to reveal the selling price. If the lowest selling price does not exist, the selling price is null. The Commission that fails to make a deal in the Set auction automatically enters the continuous auction.