Centralized delivery refers to the unified delivery of all open contracts within the prescribed time limit after the end of the last trading day; Rolling delivery starts from the first trading day of the delivery month, and (the buyer or seller, or both parties) can apply for delivery every day during the trading hours.

In the past, Zhengzhou wheat has been delivered by rolling. From the first day of the delivery month, the seller can apply for delivery at any time during the trading hours (at the place where the exchange is located). When a seller (the holder of the selling contract and the holder of the warehouse receipt) applies for delivery, the exchange host will automatically search for the buyer who has held the position for the longest time and complete the matching with the seller. This form of seller's application for delivery is called "seller's priority".

So sometimes a buyer suddenly finds that his position is gone after the close, and it has been delivered and matched! At present, both buyers and sellers can apply for delivery at any time in Zhengzhou Stock Exchange. In the past, only the seller had the right to apply for delivery, mainly for the convenience of spot manufacturers.