There are obvious problems in the borrower's repayment ability, and it is impossible to repay the loan principal and interest in full by relying entirely on its normal operating income. Interest needs to be repaid by disposing of assets, financing from outside and even implementing mortgage guarantee.

Understanding the five-level classification of loans is the classification of loan quality by banks according to borrowers' repayment ability. Mainly divided into normal, concern, secondary, suspicious and loss, of which the last three are non-performing loans.