profit economics After August 1987, for example, as the dollar fell, people rushed to buy sterling, the high-yielding currency, which rose from $1.65 to $1.90 in a very short time, up almost 20%. In order to limit the rise in the pound, the UK cut interest rates for several consecutive times between may and June 1988, falling from 10% to 7.5%, with the pound falling every time it cut interest rates. But the pound began to pick up again after the bank of England was forced to raise interest rates several times as the pound weakened too quickly and inflationary pressures increased. Any transaction can be seen as a contract between the two parties. The so-called transaction cost can be seen as the cost of the transaction contract. According to Mr Coase and others, a type of transaction costs arise from the accidental factors that occur when a deal is signed. These incidental factors may not be written into the contract due to the fact that they could not be foreseen in advance, or although they could be foreseen, they could not be written into the contract due to too many factors. Another type of transaction costs is the signing of contracts and the cost of monitoring and enforcing contracts. In 1934, professor rei, of the center for fluid mechanics, used model cars to measure the aerodynamic drag of various bodies in wind tunnels 1. The accounting income is based on the actual economic business of the enterprise, and the sales revenue obtained from selling products or providing services is deducted from the cost of actual sales revenue. These economic businesses include both external and internal transactions. Business activities with the outside world transfer the assets or liabilities of an enterprise, since it is usually a direct monetary income, so its measurement is generally accurate. The use or transfer of assets within an enterprise, as a result of a non-direct monetary balance, is usually not accurate. According to traditional accounting views, changes in market prices or expected prices are not included in the transfer of internal assets. When a transaction occurs, the price of an old asset is usually transferred to the new asset, which is the measurement of the proceeds of the transaction. The transaction method automatically deduces the process of determining income during sales or trading, as well as the cost transfer practice in accounting. Listed in just three days later, the stock has jumped 2000%, on December 18, only half a day, that day rose more than 400%, volume of more than 5 million shares, accounting for half of the total outstanding shares, by two days in a row, its market value has reached $5 billion, due to the large period of time to rise too fast, Long Fin trigger circuit breakers exchanges for many times.