درخت حوزه‌های تخصصی

Market participants use different tools basically technical or fundamental analysis to have a higher return in constructing a well-maintained portfolio. Examining the efficiency of technical strategies in creating a portfolio is the main objective of this study. Technical analysis is based on using historical trading data to launch selling and buying rules that maximize return and still control risks of loss. We use the adjusted trading data of 50 active stocks in the Tehran Stock Exchange as our sample which includes daily trading data from 2008 to 2019. We construct two types of portfolio; strategy-based portfolio versus random one. Then we calculate abnormal returns of each type of portfolio, applying the Monte-Carlo technique. Using Independent-Samples T-Test to compare means of the abnormal returns, our findings show that there is a significant positive abnormal return for both strategies applied in constructing a portfolio (0.057 and 0.062 mean difference for the first and second strategy, respectively), confirming the higher efficiency of applying technical strategies in portfolio management. Therefore, it is suggested to have and apply a strategy or combination of strategies for trading as an active participant, instead of constructing, rebalancing and maintaining one’s portfolio only by chance, since there will be undesirable results in the long-run.

Sustainability accounting by presenting a holistic view of the organization activities and providing a balanced view of its economic, social and environmental impacts and benefits, and by presenting sustainability reporting seeks to encourage business units and investors to maintain the mutual benefits of all stakeholders in the society. Given the criticisms that researchers have had about the efficiency of sustainability reporting, the purpose of this article is to develop sustainability accounting by presenting a new model that can address the challenges in sustainability accounting and can be a good alternative to sustainability reporting. Social value-added is the sum of tangible and intangible values created and added to society by a business through technological development/change and the knowledge of its manufacturing engineers and managers. In this research, to test the proposed social value added model, Nano engine oil was selected randomly and the test was performed using paired comparison of data. The results of the research showed that social value-added statement can be an appropriate report for evaluating the economic, social and environmental performance of a business entity. Nano engine oil has a social value added of 3797.2 percent compared to regular engine oil, that 15 percent of it is related to tangible value added and 85 percent to intangible value added. 

One of the most important effective elements in economic growth is the efficiency of manufacturing units. Therefore, measuring the efficiency of firms is necessary in order to increase efficiency in future planning courses. In the current research, using Stochastic Frontier Production Function, the efficiency of firms in Tehran Stock Exchange has been measured. In the above method, the efficient frontier is determined by using the Trans log production function, and the efficiency of each firm measured by the efficient frontier. The most important superiority of Stochastic Frontier Production Function is to specify the role of random and environmental elements (out of firm authorities) and inter-organizational elements (in-firm authorities) to assess the inefficiency of firms as compared to other methods. Thus, 105 firms were selected using maximum likelihood method in 2008-2017 to evaluate the research model. Results indicated that the minerals industry and cement industry with the averages of 53% and 90% had the least and most efficiency values, respectively. Separating the inefficiency values showed that the food industry and chemicals industry had the least and most inefficiency resulting from the firm authorities as 33.6% and 95.2%, respectively. According to research results, financial analysts and investors are recommended to rank the efficiency and assess the performance based on the firm authorities. Due to the importance of efficiency measurement in operational auditing, the auditors are recommended to use the current research model to assess the firm’s efficiency. Also, Organization of Industries and Mines is suggested to tackle the obstacles after identifying the elements out of firm authorities which affect the inefficiency in the firms.

This study investigates the effect of market inefficiency and environmental uncertainty on CEO risk taking. Prior research, however, have struggled to establish this relation empirically; moreover, some evidence points to the possibility that the CEO risk appetite is lower for firms active in inefficient markets. The opportunistic approach of managers leads to decisions about personal interests and imposing costs on shareholders by decreasing risk taking. In order to investigate the issue, data on companies listed in Tehran Stock Exchange, from 2008 to 2018, were extracted and a panel regression model was used to test the research hypotheses. Consistent with expected relation between market inefficiency, environmental uncertainty and CEO risk taking, the managers' risk taking decreases with respect to market inefficiency and environmental uncertainty. Managers may benefit from increased fluctuations in risk orientation, but are more sensitive than shareholders and have less restrictive choice that avoids higher risk.