Abstract
Parisians options extend barrier options in that their covenant depends on the time the underlying spends beyond a given threshold. By their nature, they are hard to price and hedge, although some quite involved methods are available. Parisians options can be valued by four different methods : Monte Carlo simulations, lattices, partial differential equations, and inverse Laplace transforms. We develop a new inverse Laplace transform method that is quick and appropriate to the problem. Our method can also be used to treat other financial problems that require inversion of a Laplace transform.