فصلنامه بورس اوراق بهادار
پیاپی 13 (بهار 1390)

A right which is claimed but can not be proved is equal to "no right". Evidences are the means which can be presented to the Court and prove the validity of the claim under the legal requirements; so, they should require specified characteristics such as signature, originality, accessibility, integrity and accuracy. Following the approval of the Electronic Commerce Act, in Iranian legal system, data message and electronic signature have also been regarded as evidence and especially accepted as "documentary evidence". Hence, if they have the required trustworthy, they can prove the claim. Following the approval of this Act and other regulations under which, the online trading and receipt of phone orders have been implemented in the securities market, currently these transactions and electronic orders can be proved before the judicial authorities with high assurance, although under ordinary not secure electronic signature.

One of the latest firm performance assessment measures is economic value added. Based on this measure, firm value depends on two factors: capital return and cost of capital. This research studies the correlation between criteria's related to economic value added (EVA, REVA, MVA) with the intrinsic value of companies and comparison with the correlation between the other variable (cost of capital) with the intrinsic value of companies listed in Tehran Stock Exchange. and specify the criterion related to economic value added (EVA, REVA, MVA) which can be appropriate to evaluate company performance and has more correlation with the intrinsic value of companies? In order to answer this question 110 year – company data are selected from the active companies listed in Tehran Stock Exchange and statistical analysis was done. The results indicate that there are significant relationships between economic value added and market value added with the intrinsic value of company. So market value added has a stronger relationship with the intrinsic value of the company among these three criteria.

In this paper, I have determined the impact of different factors on unqualified audit report over a 7- year period in 56 firms on Tehran Stock Exchange. I have found a significant relation between management performance, ownership change, privatization of auditing, opinion shopping, audit change and client size with unqualified audit report. There is a positive relation between all variables except client size with unqualified audit report in the study sample. The results of this study show that privatization of auditing market has increased audit change and it has decreased qualified audit report, and therefore, this could make opinion shopping phenomenon in auditing market. Outcomes of the research show that competition in auditing could increase unqualified audit report.

Price range limit law is a supportive policy which is applied in stock exchanges with the aim of investment risk reduction. Its advocates believe that applying this law reduces stocks price volatility and prevents shareholders excessive reaction. On the other hand, opponents believe that price range limit law increases the volatility in the coming days and decreases stock market efficiency by preventing the stock price to reach quickly to the equilibrium level. By analyzing the auto-correlation pattern of total efficiency parameter in Tehran Stock Exchange, this paper has studied the impact of price range limit law on the efficiency of Tehran Stock Exchange by two aspects: (1) delay in reaching the real price (2) its impact on investors over reaction. Due to auto-correlation diagrams, daily efficiencies have positive auto-correlation both before and after applying this law that shows slow process of information dissemination and news reflection in the market and consequently nonefficient market. Data positive auto-correlation surely goes away sooner before applying this law and efficiencies have negative auto-correlation at longer intervals. Considering that Tehran Stock Exchange is less developed than other world great exchanges, slow rate of information flow and lack of rapid response of all investors to the news can be two important factors for creating the positive auto-correlation in the stock efficiency. Statistical tests show that price range limit law has transferred more price changes to coming days by causing delay in reaching the stock to its equilibrium level. So, this law has intensified auto-correlation of positive efficiencies and therefore decreased market efficiency by slowing the reflection process of news on the stock price. In addition, there has been no significant evidence concerning the impact of this law on investors over reaction (increase or reduction).We are also witness of drop in efficiency status at Tehran Stock Exchange after applying price range limit law according to the modeling results of variation in efficiency status by using model composition with variable parameters over time with a GARCH-M model for considering non similarity of conditional variance.

In this research the effect of ownership structure variables (institutional ownership, block holder, free float) and interactive effects of these variables on dividend policy in various industries have been investigated. Cash to earning per share ratio was a proxy for dividend policy and Test of hypothesis was carried out by multiple regression analysis by generalized least square (GLS) and pooled (panel) least squared (PLS) methods. In the present study, the effect of the variables separately on dividend policy assessed by (PLS) an interactive effect of ownership structure variables by industry as dummy variable on dividend policy assessed by GLS. Statistical population reviewed is all companies listed in Tehran Stock Exchange during 1383-1387 (2001-2008) without investment companies and financial intermediaries. finally 65 companies that all required information were examined. The result showed that among ownership structure variables, institutional ownership and free float variables have significant relationship with dividend Policy. The interactive effect of institutional ownership on dividend policy in different industries was significant and different; hence, the type of industry variable can be a damper effect on the relationship between institutional ownership variables and dividend policy.

Based on the literature of the agency theory, as the agency conflicts increases, enterprises have to choose independent audit firms. Thus, in the present study, the effect of corporate governance on choosing the audit firms by the companies listed in Tehran Stock Exchange is investigated by using a sample consisting of 711 company-year observations during 2001-2010. The statistical method used is logistic regression model with panel data. The result shows that there is a meaningful and positive relationship between the percentage of institutional ownership and ownership concentration and the auditor size. However, the results related to the variables of percentage of outside directors on the board and the debt ratio show that combination of the board and the monitoring role of creditors do not have a meaningful effect on the auditor size. The results related to control variables show that there is a meaningful and positive relationship between the variables of asset turnover ratio and the company size, and the chosen audit firm. Also, there is a negative and meaningful relationship between asset turnover and the chosen audit firm. However, the results related to ROA and some dummy industry variables indicate that, in general, the size of the chosen audit firm by the companies listed in Tehran Stock Exchange is not affected by these variables.

In this research, We investigated the relationship between corporate governance mechanisms and stock liquidity in Tehran Stock Exchange. The samples of this research consisted of 72 firms during 1383-1387 (2004-2008). We used Amihud model as proxy stock liquidity and among various features, four features including institutional ownership, concentration ownership, independent directors and the existence of dominant personalities (CEO/Chairman duality), as proxy corporate governance mechanisms, selected and examined their relationship with stock liquidity. The multivariate pooled regression model is used to examine the hypotheses. The results indicate that there is significant positive relationship between institutional ownership and independent directors and stock liquidity in Tehran Stock Exchange. So, there is significant negative relationship between concentration ownership and dominant personalities (CEO/Chairman duality) and stock liquidity.

Speculators, Arbitrageurs and hedgers are the main participants in futures market in which every one does special activity based on their needs and goals. The difference between spot price and futures price and the type of relationship between the two markets are important issues for these market participants. To get access to such information, we should embark on an entire survey on the price trends in the spot market as well as futures market and the due relationship of these two marketplaces which enables us eventually to make the best price forecast on the basis of the evaluated model. In this due, the nature of the relationship between the spot and futures prices of gold coin in the Iranian markets was studied as the single active futures contract in futures market of Iran. However, with respect to the nature of the data, the bivariate GARCH model and Johansson Test were employed and the relationship between the spot and futures prices of gold coin was analyzed. Finally, as per Johansson Test results the existence of a long-term relation between spot and futures prices of gold coin in Iran were confirmed and it was also confirmed that the futures market can lead the spot price.

In this study, we examined the role of investment opportunities as a determinant of the relative importance of cash flows from operation (CFO) and accruals in firm valuation. Our analyses are based on three perspectives in the area of finance and accounting named as “the growth information hypothesis”, “the internal resource hypothesis”, “the noisy measure hypothesis”. We examined our hypothesis on a sample of 90 companies listed on Tehran Stock Exchange during the period between years 1382-1387 (2003-2008). Our findings show that in the range of investment opportunities, by increasing of investment opportunities, the value-relevance of cash flows from operation and accruals will decrease. Decreased in value-relevance of cash flows from operation and accruals would be the result of defects in accounting procedures. Research results also indicate that earnings response coefficients first decrease and then increase as investment opportunities increase

Dissemination of financial and non-financial information in different sections is the duty of firms. Management, creditors, investors and others, use the disclosed information contained in the financial reports to form judgments about the operating performance and financial position of the company. Empirical studies so far conducted by different researchers have revealed that a good disclosure improves analyst's forecasts accuracy about future earnings. The companies disclose information voluntarily or by force. Considering developing economy of Iran, SEO (Securities and Exchange Organization) as capital market authority is setting rules and regulations and all listed companies in Iran emerging market are required to fully comply with mandatory disclosure requirements. Now, the question is whether information disclosed by force improves the relationship between current stock return and future earnings, and provides more information to stockholders. Experimental investigation by using information from a sample consisting of 151 firms from among TSE listed companies during the period 1381 to 1388 (2002-2009) have shown that the disclosures made in firms reports are containing information about the future earnings, which are being utilized by investors in their decisions. In the other word, disclosed information are value relevance.

In this paper, following some studies (such as Frankel and Lee, 1998; Ali et al., 2003; Xie, 2004), by introducing the concept of "Convergence of Prices to Fundamental Values" and emphasizing on "Value to Price () Ratio", we have investigated the effectiveness of External Financial Reporting Mechanism. To do so, 87 firms from TSE for 1378-1386 (1999-2007) have been studied. The findings show that there is a correlation between Ratio and future stock return (normal or abnormal). Also, the primary source of the abnormal earnings is the convergence of prices to fundamental values of stocks. The correlation between accounting and financial reporting information with market prices is observed, and the results show that accounting information affects on forming supply and demand for stocks and therefore, the price changes. The findings of ANOVA show that Buy & Hold return is greater than the strategy return and the Price Convergence of Stock returns is greater, too.