Loan refers to a form of credit activity in which banks or other financial institutions lend monetary funds at a certain interest rate and must return them. The simple and popular understanding is to borrow money with interest.

Loans in a broad sense refer to loans, discounts, overdrafts and other borrowing funds. Banks put concentrated money and monetary funds out through loans, which can meet the needs of social expansion and reproduction and promote economic development; At the same time, banks can also obtain loan interest income and increase their own accumulation. The "three principles" refer to safety, liquidity and efficiency, and are the fundamental principles of commercial banks' loan operation.

Article 4 of People's Republic of China (PRC) Commercial Bank Law stipulates: "Commercial banks should operate independently, bear their own risks, be responsible for their own profits and losses, and be self-disciplined, and take safety, liquidity and efficiency as their operating principles."