Data released by the American petroleum institute (API) showed that U.S. crude oil inventories fell 5.2 million barrels in the week ended Dec. 15, down from an expected 35.18 million barrels. Refinery inventories fell more than expected, while gasoline inventories rose, but were less than expected. The overall API data is good and good for oil prices. Before that, what is the nature of the enterprise itself is an issue that has been ignored by traditional microeconomic theory. In the traditional microeconomic theory, is the manufacturer's production process as a "black box", namely enterprise is abstracted into a from input to output a "black box" of the pursuit of profit maximization. According to the engine displacement, divided into a miniature (1 liter), light level sedan (1-1.6 liters), intermediate (1.6-2.5 litres), senior sedan (2.5 4 liters), limousine (4 liters). In this way, if the interest rate of a country is higher than that of other countries, it will attract a large amount of capital inflow, and the outflow of funds from the country will decrease, leading to the buying of this currency in the international market. At the same time, the capital account balance has been improved, and the currency exchange rate has been raised. On the other hand, if a country is loose credit, interest rates fell, if interest rates lower than in other countries, can cause large capital outflows, foreign capital inflows to reduce, the capital account balance of payments deteriorates, while selling the currency in foreign exchange market, caused the exchange rate to fall. In theoretical economics, investment means buying (and therefore producing) capital goods - not being consumed but being used in future production. Examples include building railroads, or factories, cleaning the land, or allowing yourself to go to college. Strictly speaking, investment in formula GDP= C + I + G + NX is also part of gross domestic product. In that respect, the function of investment is divided into non-residential investments (such as factories, machinery, etc.) and residential investment (new homes). The correlation between I = (Y, I) is known to have a close relationship with income and interest rates. Higher incomes would boost higher investment, but higher interest rates would discourage investment because it would be more expensive to borrow. Even if companies choose to use their own funds to invest, interest rates represent the opportunity cost of investing in those funds rather than the interest that will lend out. 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. To shape these politicians' views, they can better explain why co-operation with fiscal authorities and foreign central Banks is in the public interest. They can release more detailed financial accounts, including individual security deals and counterparties.