Convergence analysis of option drift rate inverse problem based on degenerate parabolic equation

In this paper, we study the convergence of the inverse drift rate problem of option pricing based on degenerate parabolic equations, aiming to recover the stock price drift rate function by known option market prices. Unlike the classical inverse parabolic equation problem, the article transforms the original problem into an inverse problem with principal coefficients of the degenerate parabolic equation over a bounded region by variable substitution, thus avoiding the error introduced by artificial truncation. Under the optimal control framework, the problem is transformed into an optimization problem, the existence of the minimal solution is proved, and a mathematical proof of the convergence of the optimal solution is given. Finally, the gradient-type iterative method is applied to obtain the numerical solution of the inverse problem, and numerical experiments are conducted to verify it. This study provides an effective theoretical framework and numerical method for inferring the stock price drift rate from the option market price.