We derive the first closed-form optimal refinancing rule for mortgages: Refinance when the current mortgage interest rate falls below the original mortgage interest rate by at least (1/ψ)[φ W(-exp(-φ))], where W(.) is the principal branch of the Lambert W-function, ψ=((√(2(ρ λ)))/σ),...

We derive the first closed-form optimal mortgage refinancing rule. The expression is derived by using the Lambert-W function to solve a tractable class of mortgage refinancing problems. We calibrate our solution and show that our quantitative results closely match those reported by researchers...

We derive the first closed-form optimal mortgage refinancing rule. The expression is derived by using the Lambert-W function to solve a tractable class of mortgage refinancing problems. We calibrate our solution and show that our quantitative results closely match those reported by researchers...