In structured products like mortgage-backed and assets-backed securities, the cash flows include both principal repayment and interest. The complication arises when individual borrowers repay their loans before the maturity date. To incorporate this prepayment factor into the expected cashflows from a security, a rate at which prepayments will occur is assumed. Once the cash flows are projected based on the assumed prepayment rate, cash flow yield is obtained. Cash flow yield may be defined as the interest rate that will make the present value of the projected cash flows which is based on assumed prepayments equal to the price plus the accrued interest.