Abstract
Over the past few decades, the valuation of credit derivatives suffers from the main drawback that their models do not have closed-form solutions and require extensive use of numerical techniques to solve time-dependent partial differential equations (PDEs). Using the Lie group theory from abstract algebra we significantly simplify the valuation of the credit derivatives with time-dependent parameters. Unlike simulation or numerical based methods, our method obtains option values relatively quickly and more efficient. Exploiting the well-defined algebraic structure of the pricing partial differential equations of the default-risky bonds, the new method enables us to derive analytical closed-form pricing formulae very straightforwardly. Even though It has been pointed out that such a pricing problem is rather formidable and defies the conventional approach for the single-asset Black-Scholes model with time-dependent parameters (Bos and Ware [3]), within the framework of the lie algebraic approach, the generalization of other options is very simple and straightforward.