Time factor a transaction's expected time is a question worth considering. 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: Charlotte Nelson, of Moneyfacts, said: "only 56 providers of SVR went up, seven of which raised their interest rates by less than 0.25 percentage points, resulting in a more modest rise in average SVR. The conversion of commodity value into cost price + profit (k+p) includes the possibility of deviation from the residual value. Because profits for more than the balance of cost price, and the cost price is less than the goods value, it provides the individual capitalists in cost price above and below the value of the possibility of selling goods, so that to achieve the profit with the goods actually contains surplus value does not agree in number. The capitalist makes use of the difference between the value of the commodity and the cost price, as a driving force in the market competition. As the competition between different production department and the free flow of capital, make different special margin balance into average profit margins or average profit margins, so that the profits further into average profit, realize the amount of capital to achieve the same amount of profit. In the usual case, the average profit and the surplus value are inconsistent in quantity. The average profit is proportionately proportional to the total amount of capital in advance and not the amount of live labor that is governed by individual capital. This and make an objective truth, essentially profits is the product of capital, it is nothing to do with labor, in this way, capital on the relationship between the wage labor to make money and to be make, will be further.