Spread

Key Spread in CMS Rate Bond refers to the 1D-array of numerical additive constants s used in the calculation of the coupons according to the formula C = N(gF+s)Δt
If only one value is provided, then all coupons share that single value.
If N values are provided, then the first N coupons are paired with the N values in successive order, while the remaining coupons use the last value.
More details at Index