Journal of Industrial Engineering and Management Studies

Abstract In this research, a new emerging model for the Tehran stock exchange market is considered, and a model with realistic constraints for the mentioned market is provided. Realistic constraints are incorporated in this model for applicable purposes, one of which is the transaction cost. The limited maximum number of stocks that should be invested is also considered. Additionally, constraints have been added to the classic portfolio selection model to prevent stocks from being bought in tiny quantities and avoid over-buying some stocks. The mentioned constraint can improve diversity in the selected portfolio. One of the factors considered by many financial market investors is the amount of liquidity of the stocks they have purchased. This study also considers the amount of portfolio liquidity as one of the essential objective functions affecting the selection of the portfolio. Finally, in the model presented in the present study, the investors can have a different stock portfolio according to their preferences. The proposed model is multi-objective fuzzy goal programming, which can simulate uncertainty in the Tehran stock exchange market and provide a rational framework for investors who invest in the financial markets. As the numerical instances show, the solutions when additional constraints are added to the mathematical model are close to exact results. This difference became significant when the maximum number of stocks increased. According to the results, when the number of stocks increases, GAMS software loses its functionality, and the utilization of meta-heuristics as an option is inescapable. Finally, the harmony search algorithm with added realistic constraints has provided better portfolios in such a situation. To compare the results, a genetic algorithm was used as the competing algorithm. After solving different instances and comparing the results of the algorithms, the superiority of the proposed harmony search algorithm has been proved.