درخت حوزه‌های تخصصی

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.

Having adequate, sufficient and timely information and data is very important for investors' decision making. Processing information and allocating the asset are two fundamental tasks in the securities market and the stock price is more likely to have the nature of disclosure, information effectiveness and asset allocation efficiency. Thus, in this research, the effects of large block transactions and ownership nature on the non- financial disclosure have been investigated in the corporates accepted in Tehran Stock Exchange. Research population involves the corporates accepted in Tehran Stock Exchange for a 5-year period (2010-2014) that according to research constraints and using the systematic deletion method, the data related to 133 corporates were gathered. In this study, five main hypotheses have been suggested. To analyze the desired data and test the research hypotheses, the software of Eviews has been implemented. Results indicated that the number of large block transactions and nature of ownership are effective in non-financial information disclosure at the whole and the corporates with high transactions, those with low transactions, those in a business group and those in a diverse business group but the effect and explanatory of dependent variables by the independent ones vary at each level.

In this paper, Black Scholes’s pricing model was developed to study American option on future contracts of Brent oil. The practical tests of the model show that market priced option contracts as future contracts less than what model did, which mostly represent option contracts with price rather than without price. Moreover, it suggests call option rather than put option. Using t hypothesis test, price differences were obtained, which can serve as a useful strategy for traders interested in arbitrage practice and risk hedging. This research introduces an optimal strategy (both for call and put option states and buy and sell of future contract ) for all options of buy and sell future contracts with and without price. In this research, six-month data of the end of 2015 about oil option and option of future contracts of North Sea oil for three different maturities were used.

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.

Investor decision making has always been affected by two factors: risk and returns. Considering risk, the investor expects an acceptable return on the investment decision horizon. Accordingly, defining goals and constraints for each investor can have unique prioritization. This paper develops several approaches to multi criteria portfolio optimization. The maximization of stock returns, the power of liquidity of selected stocks and the acceptance of risk to market risk are set as objectives of the problem. In order to solve the problem of information in the Tehran Stock Exchange in 2017, 45 sample stocks have been identified and, with the assumption of normalization of goals, a genetic algorithm has been used. The results show that the selected model provides a good performance for selecting the optimal portfolio for investors with specific goals and constraints. 

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.

In this study business operations and liquidity and credit risk on price fluctuations on the stock exchange since 2010 to 2013 has been Tehran distance. The sample consisted of 76 company The systematic elimination method is selected. The company had a total of 304 years, in this study, the hypothesis of linear regression and correlation to analyse the data and test hypotheses Eviews software is used. The results show a direct linear relationship between the number of business deal with price volatility as a factor in companies listed on the Tehran Stock Exchange respectively. In addition, liquidity and credit risks and price fluctuations affect the relationship between business activities

<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>