درخت حوزه‌های تخصصی

Value at Risk model based on a switching regime approach was used in this study to optimize portfolios consisting of industry index (petroleum products, investment, chemical products, and metal products). For this purpose, the VaR of returns on index should first be extracted through parametric models of the (GARCH) family in each of the above industries by using regime transitions. After the risk of return on index is obtained for each industry, the optimal portfolio is created in the next step based on VaR minimization, and the optimal value of each industry is determined in the portfolio. According to the results, (MRS-FIEGARCH) model had no superiority in VaR estimation over the other parametric models of the GARCH family. In fact (MS-EGARCH-t) was introduced as the optimal model. Among the designated industries, returns on indices followed regime transitions only in chemical products and investment by showing asymmetric reactions to external shocks. Moreover, the optimal weights were on the rise in the industries where VaR decreased over time, whereas the optimal weight of the portfolio decreased in the industries where VaR increased over time. The higher share of an optimal portfolio belonged to the industries where stock returns had lower rates of VaR. The risk-return-ratio was employed to show that the optimal portfolio with a risk rate was measured by considering the switching regime was superior over the optimal portfolio with a risk rate extracted without considering the switching effects. To create an optimal portfolio, it is then recommended to make investments in the industries characterized by higher stability in prices and lower fluctuations in stock returns in the long run. This approach can be employed to obtain the best results from optimal portfolio preparation in the worst-case scenario of the market fluctuations.

A manager’s personality and psychological attributes may influence his or her performance, thereby affecting the quality of financial reporting by companies. On the one hand, today there is an increasing requirement for protecting the interests of investors as providers of investment and the most important group of accounting information and financial report users. The development of audit committees is among the mechanisms expected to be effective in protecting the interests of different groups of accounting information and financial report users. In order to act effectively, an audit committee must be independent. Therefore, the present study aims to examine the role played by the independence of audit committee members as a quality of an audit committee to identify how it may moderate the relationship between managers' narcissism and real earnings management in the firms listed in the Tehran Stock Exchange (TSE) using a statistical sample consisting of 642 observations (year-firm) over the period 2013-2018. The findings obtained through hypothesis testing using statistical analysis of panel data suggest that independence of audit committee members does not moderate the relationship between CEO's narcissism and real earnings management through abnormal cash flow, real earnings management through abnormal production, and real earnings management through abnormal discretionary expenses. Thus, the independence of audit committee members as a moderator cannot moderate the relationship between CEO's narcissism and real earnings management

Stock Exchange Investors have paid more attention to the banking group in recent years so that in many cases, the direction of the banking index has changed the general direction of the market. Therefore, exploring the banking index fluctuation is important from the point of view of investors as well as the direction of the market. The purpose is to examine the effectiveness and direction of news, as one of the most important factors in the formation of volatility, on the banking group index in Tehran Stock Exchange by using 1460 daily records during 2018-2019 and the GARCH family's method. The data were collected for four different newsgroups, including economic, political, psychological, and financial. After that, the news that had more relationship with the banking group was separated to underscore in the weighting stage and divided into the positive and negative news, according to the perspectives of capital market experts and economic elites. The results indicated that newsgroups have a significant effect on the group index, and only the negative political model on the banking group has an asymmetric effect. The results indicated that political and economic news has a positive and significant impact on banking index fluctuations.

The present study investigates the impact of macroeconomic and bank-specific variables on non-performing loans (NPLs). To avoid the identification problem, two models are employed to address this impact. The first one tests the effect of macroeconomic variables including the growth of oil revenues, inflation, and the growth of GDP without the oil sector on the growth of NPLs. Data is quarterly over the period 2004:3 to 2019:3. The transition variable in this setup is the growth of oil revenues and its threshold is 9 percent, which divides the sample into oil booms and oil recessions. According to the results, inflation has a significant positive effect on NPLs. During the oil boom, oil revenues decrease the NPLs. Due to the immense size of the government and its current and capital expenditures, when oil revenues are lower, the government forces banks to allocate loans to finance projects with long maturity. Furthermore, the present study used PSTR to test the impact of bank-specific variables consisting of interest rate spread, loan loss provision, loan to deposit ratio, and NPLs. To do so, monthly data of 10 banks is used over 2016:04 to 2020:12. The transition variable is the interest rate spread at 1 percent, which categorizes the banks into two groups of good and bad. Good banks collect deposits with a low-interest rate and allocate high-rate loans with less chance of default. So, interest spread is the most important prominent determinant of decreasing NPLs, while the loan to deposit ratio is dependent on the banks belonging to which group. For good banks, the loan to deposit ratio decreases the NPLs, while for bad banks, it worsens the growth of NPLs.