A method of simulating future cash flow for a given asset allocation under a variety of economic conditions, measuring the frequency of failure of the cash flow to avoid one or more predefined risks. Assigning user-selected weights to avoidance of specified risks and alternative user-selected weights to maximization of rate of return, the invention utilizes the cash flow simulation to produce a performance index. By methodological testing through asset allocation adjustments, the optimum performance index is determined, thereby identifying the optimum asset allocation.