Perturbation analysis, including perturbation bounds, is developed for nonlinear operator equations of the form X = Q ± A*F(X)A, under perturbations of the given operators Q (which is assumed to be positive definite) and A and of the given operator function F(X) which takes self-adjoint operator values. Stability of fixed points under suitable map perturbations serves as the main technical tool. More detailed analysis is provided in the particular cases where F(X) is a power map. © 2006 Society for Industrial and Applied Mathematics.