فصلنامه بورس اوراق بهادار
پیاپی 46 (تابستان 1398)

Although firms are releasing good news about meeting a benchmark, they have incentives to hide the tools used to achieve it. In other words, when reported performance differs from underlying fundamentals, it is expected that managers try to make it harder for investors to identify such earnings management behavior and the underlying performance. The present study examines the effect of earnings management on readability of financial reporting of firms listed in Tehran Stock Exchange. The statistical population of the research is the firms listed in Tehran Stock Exchange during the period from 2011 to 2015 and the relationship has been investigated in 350 firms-years. The results of this study indicate that earnings management has a positive effect on the financial reporting readability Financial constraints has a positive effect on financial reporting readability. In addition, the control variables include firm's size and firm's age have a positive effect and agency costs and firm's growth have a negative effect on the financial reporting readability. While financial leverage and book value to market value have no effect on financial reporting readability.

This paper peruses forward premium and influential factors affecting it in Iran electricity market and energy exchange transactions. In this study, Bessembinder and Lemmon (B - L) equilibrium theory as an electricity futures pricing model investigates. First, using Merton's jump diffusion model, electricity prices forecasted, then ex-ante forward premium calculated and the last B - L theoretical basis examines using markov regime switching model. The results confirm Bessembinder and Lemmon model partially. Defects observed in the market originates from illiquidity, fixed tariffs in different sectors , inactive position of consumers and imperfect restructuring in power sector. So, changes in the regulation by creating entrance opportunity for new participants such as speculators and also the electricity retail allowance issuance are recommended. Second subject is offering some guidance for the power plants about suitable time for futures transactions that carrying out in usual demand seasons such as fall and spring is advised.

Establishing an effective internal control system in economic entities increases the effectiveness and efficiency of operations and ensures the reasonable assurance of the quality of reporting and compliance with laws and regulations. According to organizational theory, companies with an aggressive strategy in comparison to companies with a defensive strategy are likely to report more significant weaknesses in internal controls. The aim of the present research is to examine the relationship between the business strategy and internal control over financial reporting of accepted companies in Tehran Stock Exchange. In this research, 135 companies have been selected during the period of 2010 to 2017 from the accepted companies in Tehran Stock Exchange. Research findings indicate that there is a direct and meaningful relationship between business strategy and the existing weakness of internal controls in business entities. On the other hand, there is a positive and meaningful relationship between the business strategy used by the business entity and the improvement of internal control weaknesses in the coming years. The findings suggest that the business strategy can be considered as a useful indicator in assessing the strength of internal controls of the companies.

Oil is the main source of energy and one of the important factors in promoting economic activities. The unconventional fluctuations in the price of this product and the uncertainty resulting from it have increased the prices of other goods and services produced. Hence, the purpose of this study is to optimize the portfolio of government’s assets and define the best investment strategy to adjust these fluctuations. In this regard, a portfolio with three assets of oil, capital market and gold market is defined for the state, and then its utility function is introduced. The optimal weights of each of the above calculated assets are evaluated by implementing the first condition of optimizations. After that, information about the oil price, value of capital market and the price of gold between 2012- 2016 was received, and according to the average, the current weight of assets in the government’s portfolio is estimated and compared with the current weight of government’s assets.

Investors myopic means more than realizing short-term earnings and less than the actual valuation of long-term earnings by active investors in the capital market. Investors myopia leads to behavior change company management and Instead of concentrating and planning to enhance long-term performance, companies focus on current and short-term performance, which may increase the stock price crash risk in the long run. The purpose of this study was to investigation the effect of investors myopic on the stock price crash risk in listed companies in the Tehran Stock Exchange. Information needed for the study of the financial statements of 150 Company in the period of years 1389-1395 has been collected. To test the research hypotheses, the multivariate regression model has been used with panel data using fixed effects method. For the measurement of myopia investors from the Del Rio & Santamaria (2016) and for measuring stock price crash risk also fluctuate bottom-up model of Chen et al (2001) have been used. The findings of the research hypothesis and show that investors myopic has a positive and significant effect on the stock price crash risk.

The capital structure and the financing policy of companies is a subject that has always been of interest to theorists and researchers.On one hand,the lower debt financing cost and on the other hand,the low risk of equity financing has created a number of theories on the appropriate combination of financing in these two ways. The theory in this context believes that the company must be financed through debt until it can meet its obligations.So,the issue of finding a model that measures the capacity of debt in companies is very important. The goal of this research is providing a model for measuring debt capacity,so that financing from the debt instead of equity,keep the company away from the risk of failing to meet its obligations while saving financial costs.The approach used in this research is the securities market approach.It means that the companies have been registered in the securities exchange are considered as the basis of debt capacity,due to the necessity of observing standards.The statistical population of the study consisted of 154 companies without penalty for late payment during the period from 1390 to 1396.To calculate the debt capacity,specific corporate variables are used and the regression model is fitted in the form Panel data at the level of each industry.The result of the study is the achievement of ten models for estimating debt capacity for ten industry groups.At the end, the models obtained for the company were tested for companies with penalty for late payment, which indicated that the ratios were correct.