We discuss the application of orthogonal polynomial to estimation of probability density functions, particularly for accessing features of a portfolio's profit/loss distribution. Such expansions are given by the sum of known orthogonal polynomials multiplied by an associated weight function.However, naïve applications of expansion methods are flawed. The shape of the estimator's tail can undulate, under the influence of the constituent polynomials in the expansion, and can even exhibit regions of negative density.This paper presents techniques to redeem these flaws and to improve quality of risk estimation. We show that by targeting a smooth density which is sufficiently close to the target density, we can obtain expansionbased estimators which do not have the shortcomings of equivalent naïve estimators. In particular, we apply optimisation and smoothing techniques which place greater weight on the tails than the body of the distribution.Numerical examples using both real and simulated data illustrate our approach. We further outline how our techniques can apply to a wide class of expansion methods, and indicate opportunities to extend to the multivariate case, where distributions of individual component risk factors in a portfolio can be accessed for the purpose of risk management.