1. What is the Z-spread? How is it calculated? What is the difference between the z-spread and the nominal spread? Discuss Solution Z Spread is also called as the Zero Volatility Spread or the Yield Curve Spread. It is the spread which makes the price of a security equal to the present value of its cash flows. It is also called as the static spread.. It is used for the analysis of an asset swap. A nominal spread used one point on the treasury yield curve to determine the spread at a single point which is equal to the present value of its cash flows..