APPROXIMATIONS OF BOND AND SWAPTION PRICES IN A BLACK–KARASIŃSKI MODEL
Abstract
We derive semi-analytic approximation formulae for bond and swaption prices in a Black–Karasiński (BK) interest rate model. Approximations are obtained using a novel technique based on the Karhunen–Loève expansion. Formulas are easily computable and prove to be very accurate in numerical tests. This makes them useful for numerically efficient calibration of the model.