fatemeh dadbeh - Ph.D. student of financial management, Faculty of Management and Economics, Science and Research Branch, Islamic Azad University, Tehran, Iran
Maryam Khalili Araghi - Assistant professor and faculty member of Faculty of Management and Economics, Science and Research Branch, Islamic Azad University, Tehran, Iran
Hashem nikoumaram - Professor and faculty member of Faculty of Management and Economics, Science and Research Branch, Islamic Azad University, Tehran, Iran

Determining an effective approach to assessing portfolio performance is one of the most important modern topics in the field of investment management. Accordingly, evaluation criteria for an investment project cannot be selected only based on its high return. The models developed for evaluating portfolio performance in terms of both risk and return are not based on the fundamental approach to financial elements. Assessing the acquisition performance has been one of the most important issues in finance for a long time and many studies have developed models to determine the optimal portfolio. As the problems with these models have been detected over time, they have been replaced with new models. In this study, the generalized method of moments (GMM) was used to explore the factors affecting the portfolio performance of stock firms in terms of accounting and economic factors. The research sample included the most efficient firms listed on the Tehran Stock Exchange. The results of the study indicated that the economic approach is more efficient than the accounting approach with an explanatory rate of ۰.۸۲. Therefore, most investors consider the economic approach in their acquisition decisions.

Portfolio performance, Accounting Approach, Economic Approach, the Generalized Method of Moments (GMM)