Portfolio optimisation: A fuzzy multi-objective approach

Markowitz's classical model and other models derived from it have raised the portfolio problem using statistical instruments that assume a regular and efficient market. In this paper, the authors propose an alternative method using fuzzy numbers to represent the uncertainty of the future return on assets. Subsequently, we define measures for risk and for excess return on a portfolio. The resulting problem is a nonlinear multi-objective program with fuzzy parameters. Finally, we introduce one method to solve the resulting problem and an example.