Because of the large value of houses, even in countries or regions with high per capita income, it is difficult for buyers to raise enough funds for buying houses at one time. If all property buyers have to wait until the purchase price is complete before buying a house, it will take at least ten years, and it may take decades, and during this long waiting time, they will have to pay the expenses incurred by renting a house. In recent years, due to the participation of financial institutions, banks have issued loans to property buyers, enabling them to obtain housing in advance. For real estate development companies, banks provide loans to property buyers. Allowing buyers to buy a house in advance is conducive to the turnover of real estate development enterprises to withdraw funds in order to obtain more profits. For banks, if loans are issued directly to real estate development companies, the houses built by the development companies with loans cannot be sold quickly, which will inevitably affect the repayment ability of the development companies. If the loan is issued directly to the buyers, the buyers will use all the loans they get to buy a house. Because the loan amount given to buyers is lower than the house price, buyers themselves have to invest a sum of money to buy a house, and because buyers use the purchased house as collateral when obtaining loans, the reliability of repayment is fully guaranteed. This kind of mortgage loan is beneficial to buyers, real estate development companies and banks, and promotes the prosperity of the real estate market. So it is more popular in recent years. Some real estate development companies began to call this kind of mortgage loan "mortgage", and some advertisements for selling houses marked "provide ×× mortgage", that is, the proportion of loans that banks can provide to buyers. For example, "60%" can provide loans of 60% of the house price. For the sake of loan security, banks can only provide loans of 70% of the house price at most. Mortgage and mortgage are not exactly the same. A more appropriate explanation for mortgage is the mortgage loan for home buyers. The purpose of the loan is to buy a house (mainly a house). Not all loans secured by houses can be called mortgage loans.