Investigating the Calendar Effect of the Holy Month of Ramadan on the Capital Market: a Fuzzy Group Decision-making Approach

In recent years, investors have realized that there are a number of irregularities (calendar effects) in the capital market through which additional returns can be obtained. In calendar irregularities, time is the factor that affects the capital market. Such effects are called calendar effects. Therefore, the purpose of this study is to identify and analyze the calendar effect of the holy month of Ramadan on the most important features of the capital market. The research method is applied in terms of purpose and descriptive-survey based on the nature and research method. The statistical population of this study includes university professors of accounting, analysts and trading experts in the Iranian capital market. In this study, using the research background and referring to eight experts and interviewing them, 6 indicators were identified as important features of the capital market that can be affected by the calendar effect of the holy month of Ramadan. Then, using 14 questionnaires, experts were asked to determine the causal relationships of these indicators. Finally, in order to explore the network of cause and effect relationships, to determine the degree of effectiveness and impact of each of the indicators and their prioritization, fuzzy hierarchical analysis, fuzzy dimtel approach and fuzzy TOPSIS were used. According to the results, capital risk is the most important indicator. This result indicates that this indicator is subject to severe changes during the holy month of Ramadan and it is necessary to pay attention to it. Then the indicators of trading volume, unsystematic risk, share return, liquidity risk and adjusted beta are important, respectively. Also, trading volume was recognized as the most effective indicator. Therefore, trading volume has a greater impact on other indicators. Also, non-systematic risk was identified as the most effective indicator.