1848, 82 businessmen in Chicago initiated the establishment of the Chicago Stock Exchange (CBOT). In fact, the original CBOT was not a market. It was not until 185 1 that the Chicago Board of Trade introduced forward contracts, and 1865 introduced standardized contracts, and at the same time implemented the margin system. Subsequently, at 1882, the exchange allowed Rio Tinto to be exempted from liability through hedging, which further promoted the participation of speculators and increased the liquidity of the futures market. The clearing association was established in 1883. After the establishment of 1925 BOTCC, all transactions of the Chicago Board of Trade have to enter the clearing company for settlement, forming a settlement institution in the modern sense.