Methods and systems are provided herewith for rating a likelihood of payment of one or more cash flows. A computing device determines a probability of payment for one or more payments on a payment schedule for each of one or more debt instruments of a debt instrument portfolio. The computing device may also determine a portfolio cash flow rating of the debt instrument portfolio based on the quantity and purchase price associated with each of the one or more debt instruments, the probability of payment for the one or more payments, a current market price of each of the one or more debt instruments, a net present expected value of the one or more payments in the payment schedule for each of the one or more debt instruments, and/or a credit rating of one or more issuers associated with the debt instruments.