The landlord is talking about cross-market arbitrage. . Cross-market arbitrage refers to the activity that speculators use the futures prices of the same commodity in different exchanges and buy and sell futures contracts in two exchanges at the same time to make profits. The specific operation method is that the futures exchange buys futures contracts for one delivery month and sells futures contracts for the same delivery month at another exchange. When the price difference of the same commodity in two exchanges exceeds the transportation cost of the commodity from the delivery warehouse of one exchange to the delivery warehouse of another exchange, it can be expected that their prices will shrink, reflecting the real cross-market delivery cost in a certain period in the future. For example, if the price of wheat is much higher than that of Kansas City Futures Exchange, which exceeds the transportation cost and delivery cost, then a spot dealer will buy wheat from Kansas City Futures Exchange and transport it to Chicago Futures Exchange for delivery. In China, the listed products of the three exchanges are different, and there is no way to connect with foreign exchanges. Therefore, cross-market arbitrage cannot be achieved.