In the early 20th century, famous American economist elvin fisher developed the theory of economic gain. In its book "the nature of capital and yield", first, the concept of yield is analyzed in terms of the performance of earnings, and three different types of benefits are proposed: Ford motor co., in 1915, produced a car that was different from a horse model The accounting income follows the historical cost principle and the matching principle, which is conducive to the objective reflection of the business management responsibility of the enterprise management authorities. But, due to the historical cost principle inherent defects, especially according to the present value of revenue and expenses by historical cost line, makes the calculation of accounting earnings lack of inner logical unity, and the matching principle is difficult to carry out, so that the book value of assets can not reflect its real value, cost cannot be fully compensated. And the economic benefit is measured in the current value, which reflects the actual value of the asset, which is beneficial to the full compensation of the cost. In the face of market failure, coase has given the opposite answer: external-utility problems can be solved by explicitly using the market, without government intervention. And zhang wuchang is more absolute, he said that there is no so-called external utility, there is only unclear property rights. Anyway, coase brought revolutionary innovation to market concepts. He made it clear that the key to the market was not the "price mechanism" of impersonal machinery, but the power of participants in economic activity. Point 2: look at the mortgage. The p2p platform is a credit loan or a mortgage. If it is a mortgage, it depends on what the mortgage is mainly, such as real estate, vehicles, etc., the loan risk of the mortgaged property is much smaller than the credit loan. If there is a risk, the company will sell the mortgage of the borrower to the investor. Wealth managers say that not only the collateral, but also the mortgage rate, which is the percentage of the value of the debt and the collateral. The mortgage rate is mainly to prevent the mortgage from not sufficient to cover the debt. If it is not, the risk of investment will increase and the situation of repeated mortgage will be avoided. For a deal that is winning money, it is not as easy to make a deal as it is to make plans to deal with the loss of money. There are many possibilities. Philip Hammond has been trying to persuade conservatives that tax increases and spending cuts are needed to reduce the deficit.