Investment portfolios undergo a calibration procedure to improve their efficiency and stability. Any set of portfolios could be selected for calibration. If said portfolios represent a result of a portfolio optimization or asset allocation, then using original model inputs, an optimization procedure is performed to compute an original efficient frontier and a set of frontier portfolios is selected for calibration. A plurality of random samples of modified optimization inputs based on the original inputs is generated. For each random sample of inputs a modified efficient frontier is computed using the portfolio optimization model with modified inputs. Each portfolio selected for calibration is projected on the modified efficient frontier to create a corresponding modified calibration portfolio. Calibrated portfolio is created by averaging its calibrations. Calibrated efficient frontier is created by averaging all calibration portfolios for each selected portfolio on the original frontier.