In order to extrapolate the sCI results to the FCI limit, we have adopted the method recently proposed by Holmes, Umrigar and Sharma in the context of the SHCI method. It consists of extrapolating the sCI energy, E (0) , as a function of the second-order Epstein-Nesbet energy, E , which is an estimate of the truncation error in the sCI algorithm, i.e E ≈ E FCI -E (0) . When E (2) = 0, the FCI limit has e ectively been reached. is extrapolation procedure has been shown to be robust, even for challenging chemical situations. Below, we propose an improved extrapolation scheme which renormalizes the second-order perturbative correction.