(Subprime loan+doubtful loan+loss loan)/various loans × 100%. Non-performing loan ratio refers to the ratio of non-performing loans of financial institutions to the total loan balance, and the calculation formula of non-performing loan ratio is (subprime loans+doubtful loans+loss loans)/loans × 100%. Non-performing loans are divided into five categories according to the risk basis: normal, concerned, secondary, suspicious and loss, of which the latter three categories are collectively referred to as non-performing loans.