For securitized asset pools the pass-through rate is the interest rate less management costs and other fees have been deducted. For mortgage-backed securities, the pass-through rate is also referred to as the coupon rate. Regardless of what it’s called, the pass-through rate will always be lower than the interest rate. For example, imagine that a mortgage lender originates fifty million dollars of mortgage loans at an interest rate of 6.25%. These mortgages are securitized and sold as an investment asset yielding 5.75% interest, with the other .5% interest satisfying the management costs and guarantee fees.