There are computerized processes for financial planning for individuals and groups whose financial portfolio would be subject to tax on certain events. But these processes do not take into account these taxes when optimizing investment decisions, since taxes levied on investment outcomes, typically on income and realized capital gains, may have an important impact on net portfolio results. This invention is a method for transforming the usual pretax information for calculation of an efficient frontier, unique to an investor's portfolio, in such a manner that any portfolio on the calculated frontier is efficient after incorporating the effect of taxes on the risk and expected return of each asset class permitted in the investor's portfolio. This invention addresses how this may be done and how certain facets of the process may be incorporated into a computer program or system so as to provide convenience to the potential user.