درخت حوزه‌های تخصصی

Portfolio theory assumes that investors accept risk. This means thatin the equal rate of return on the two assets, the assets were chosenthat have a lower risk level. Modern portfolio theory is accepted byinvestors who believe that they are not cope with the market. Sothey keep many different types of securities in order to access theoptimum efficiency rate that is close to the rate of return on market.One way to control investment risk is establishing the portfolioshares. There are many ways to choose the optimal portfolioshares. Among these methods in this study we use loss functions.For this, we choose all firms from the year2011to the end of 2015that had been a member in the Tehran Stock Exchange. The resultsof this research show that the likelihood functions have the bestperformance in Forecasting the optimal portfolio allocationprob-lem.

<span lang="EN-GB">Reliability and efficacy of accruals and cash flows which are among the most important factors affecting dividend deviation have always been in question and subject to anomalies. The presence of these anomalies in accruals and cash flows and its effect on future returns and the consequences that they can have in country’s investments are the main motives to choose this issue for the current study. The statistical population includes all the accepted companies in Tehran Securities Exchange in the time domain of 2005 to 2012 that were studied after the systematic elimination of 153 companies from the original sample and 45 companies from the dividend continuity sample. The research is descriptive and correlational and the research assumptions are tested using statistical techniques. The results indicate that the first assumption based on rational pricing related to cash flows and total accruals in the companies in Tehran Securities Exchange is rejected in the study period; this indicates anomalies and regarding the significance of the coefficient related to the total accruals among the group of companies under study, the companies with low accruals have a higher abnormal return compared to companies with high accruals.</span>

One of the main instruments of accountability in economic activities is auditing. But despite the extent of audit work, determining the fees for this service in our country is not based on a scientific model and reasonably we cannot claim, according to firm's characteristic and with what cost, the work would be done. In this regard, we have tested the impact of transparency of accounting information on audit fees. This paper statically sample consists of 64 firms that are analysed in period of 2011-2016 which obtaining total 320 firm-years; for data analysis, we used Kolmogorov-Smirnov for normality of the data, Durbin-Watson test for test of errors independence or absence of autocorrelation, and finally with the help of t-statistical tests, calculated probability is judged and assessed for each of the hypothesis. There are five main hypotheses in present study. Testing hypotheses is taken using panel data and for data analysis we used multivariate regression estimation and SPSS19, EXCEL and Eviews7 software. After designing and testing hypotheses for each hypothesis, it was concluded that the relationship between transparency of accounting information and auditing costs is established at all levels of the company and also at the corporate level companies with low financial leverage. If the relation between transparency of accounting information and auditing costs at the corporate level with high financial leverage is high, there is no significant linear relationship between high cash and low cash.

However, the free cash flows scale is important for the financial health of the company, but it has also its own limitations. Moreover, it’s not immune from accounting tricks. Free cash flows can be considered as a measure of value for shareholders of listed companies on Tehran Stock Exchange. The managers of these companies have tended to use the earnings management for managing the free cash flow and ultimately shareholder value and wealth. The main objective of this study is to investigate the interactive effect of institutional ownership and board independence on the relationship between excess free cash flow and earnings management in the Tehran Stock Exchange. The study is applied and correlation research by its objective and nature. The variables used in this study have been extracted from the financial reports of listed companies in Tehran Stock Exchange and the web page of Tehran Stock Exchange in the period of 2009 to 2015. The results suggest that, "institutional ownership" and "board independence" on the relationship between "surplus free cash flow and earnings management" had no significant effect.

Nowadays, business groups play an outstanding role in financial markets. Corporates in the trading groups are able to use technology, capital, human resources, productions and services of other members in the group in addition to their own resources and capabilities. Thus, this paper studies the effect of business group affiliation on cash holdings and return on equity. The sample involves 94 corporates among those accepted in Tehran Stock Exchange. In this research, the effect of business group affiliation on cash holdings and return on equity during 2010-2015 has been investigated; in total, it includes 564 observations for the research. Statistical method applied here is the multivariate regression in the data panel way. Results achieved by the research hypotheses indicate that there is a significant relationship between business group affiliation, cash holdings and return on equity.