Pricing perpetual put options by the Black–Scholes Equation with a nonlinear volatility function

We investigate qualitative and quantitative behavior of a solution of the mathematical model for pricing American style of perpetual put options. We assume the option price is a solution to the stationary generalized Black–Scholes equation in which the volatility function may depend on the second de...

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Bibliographic Details
Main Author: Grossinho, Maria do Rosário (author)
Other Authors: Faghan, Yaser Kord (author), Ševčovič, Daniel (author)
Format: article
Language:eng
Published: 2022
Subjects:
Online Access:http://hdl.handle.net/10400.5/24431
Country:Portugal
Oai:oai:www.repository.utl.pt:10400.5/24431
Description
Summary:We investigate qualitative and quantitative behavior of a solution of the mathematical model for pricing American style of perpetual put options. We assume the option price is a solution to the stationary generalized Black–Scholes equation in which the volatility function may depend on the second derivative of the option price itself.We prove existence and uniqueness of a solution to the free boundary problem. We derive a single implicit equation for the free boundary position and the closed form formula for the option price. It is a generalization of the well-known explicit closed form solution derived by Merton for the case of a constant volatility. We also present results of numerical computations of the free boundary position, option price and their dependence on model parameters.