If a payoff stream depends on both a fundamental and possible interventions of an authority, the asset pricing problem is usually characterized by regime switching models. In this paper, the fundamental is modeled as geometric Brownian motion. By Wiener-Hopf factorization of an EPV (expected present value) operator, concrete steps are provided to calculate the EPV of a perpetual payoff stream. Furthermore, the closed-form expressions of asset prices with surged limit and decline limit are given.