Today, free flow of information is one of the basic characteristics of different markets. Based on this, one of the most important issues in the growth and development of stock markets is the disclosure of information that influences decision makers in this market. On the same basis, there are several regulations on disclosure of information in stock markets. One of the main challenges in the disclosure of information is the scope of information disclosure in such a way that the information is published correctly and at the right time, while the disclosure of information takes place in such a way Making it possible to provide a precise picture of the company's situation. Accordingly, in the present paper, we will examine the comparative scope of the disclosure of information in the initial release of Iranian law and the rights of the United States as one of the foreseeable future in the field of securities, and finally, it will be determined that the regulation in this area is based on the necessity The disclosure of credible information is based on the company's status, since it is based on the confidentiality of information, while exceptions are made for the non-disclosure of corporate secrets and the prevention of harm to companies in emergencies.

Disclosure of information as an element of financial reporting system is affected by many factors of organization: among these factors, organizational concentration is very important. Because we have expected in the decentralization organization, with the development of accounting information systems, disclosure of information extensively aggregated. Therefore purpose of this study is an investigation the impact of organizational centralization on both forms of disclosure of information (mandatory and voluntary). In this regard with data collection related to the organizational concentration of the listed companies in Tehran Stock Exchange by questionnaire of Robbins's organizational centralization in 2015, the effect of organizational centralization on the disclosure has been studied. The results show that organizational centralization has affected on mandatory and voluntary disclosure of information is very significant, and information disclosure level is reduced to more centralized organizations. This finding help to development of literature related to factors affecting the disclosure of information, also its help manager in making good decision in the organization and finally it helps in transparency of information and improved economic decision-making.

The purpose of this study is survey of Factors influencing voluntary disclosure of information. Disclosure of voluntary information is disclosure beyond legal obligations, which have been formulated by legislative bodies and play an important role in reducing the information asymmetry between managers and outside investors plays. Research shows that Agency theory (due to a conflict of interest between the manager and owner), signaling theory (due to asymmetric information), the theory of capital need (the need to attract foreign investors) and legitimacy theory (because of the need to continue working and social needs) are the theories that represent voluntary disclosure of information.in the case of Voluntary disclosure, managers are doing such Disclosures, when its benefits exceed its costs. In this article we review the theories of voluntary disclosure, costs and benefits of disclosure of information, Motivations to voluntary disclosure and Constraints on voluntary disclosure of information.

The purpose of this study is to investigate the relationship between the quality of company's risk disclosure with information asymmetry under Firm-Riskiness, economic downturn and institutional Analysts in Tehran Stock Exchange To achieve this aim 100 firms were evaluated over the period of 2009-2014.To test the research hypothesis, random data pattern is used. The analysis of risk information disclosure in this study have been investigated by content analysis of the various sections of board of directors Performance Report. The role of the present study is based on the standard which was introduced by Linsley and Shrives (2006). The results of current study show that there is a significant negative relationship between quality of risk disclosure and information asymmetry (bid-ask spread and volume of transactions). Also level of firm-riskiness regarding to level of technology and existence of institutional Analysts in volume of transactions case had a significant impact on the relationship between quality of risk disclosure and information asymmetry. But in Tehran Stock Exchange, risk information disclosure in different Economic conditions has a same impact on information asymmetry.

Voluntary disclosure is a surplus information on the legal requirement that includes financial and non-financial information for the more clarity of the company's processes. Voluntary disclosure as a kind of informed mechanism may be associated with different processes in the company. As a result, companies, based on the composition of their board of directors, make decisions about the voluntary disclosure of information and may vary according to the type of political and non-political directors. The purpose of this study was to investigate the effect of political connection on the information voluntary disclosure in companies listed in Tehran Stock Exchange. In this regard, numbers of 124 companies were selected for the period from 2012 to 2017. To measure voluntary disclosure, the Botosan (1997) checklist and for measuring political connections, political cost index from Faccio (2006) has been used. The panel data approach was also used to test the research hypotheses. The results showed that political connection has a negative and significant effect on the voluntary disclosure of information. In fact, companies that have more political connection are more inclined to voluntarily disclose information.

The quality of disclosure of information in financial statements in protecting of investors' interests and reducing information asymmetry plays an important role in the transparency of the capital market. Empowered executives have more aware of the state of firm and industry and in different situations can signal to capital markets by increasing the level of disclosure of information and reduce the agency cost .In this research with sample consisted of 520observations (firm-year) listed in Tehran Stock Exchange in the period 2010- 2015 to explore the relationship between disclosure quality and manager's ability with emphasis on conservatism .The findings show, managers' ability has a positive and significant impact on the quality of information disclosure and negative and significant relation to the quality of information disclosure. But there was no evidence of conservatism influence on the relationship between manager's ability and disclosure quality.

High Transparency of information can be influential on the Stock price synchronicity and crash risk by reducing information asymmetry and information risk. On the other hand, according to the signal theory, the Stock price synchronicity and crash risk can also affect the level of information disclosure . Therefore, This study aims to examine the interaction relationship between voluntary disclosure of information with Stock price synchronicity and crash risk in the companies listed on the Tehran Stock Exchange. The statistical population of the study has been determined using systematic knockout method; which includes 66 companies for a period of 8 years during the years 2008 to 2015 .To test the research hypotheses has been used the system of simultaneous equations and analysis of two-stage regression coefficients. Measuring the Level of voluntary Disclosure of Information is done based on the weight index with the same level of importance and using a checklist containing 10 dimensions and 307 Voluntary components. Stock price synchronization calculate Based on daily market and industry returns in a financial year and its impact on the daily returns of the company. Also to measure the Stock price crash risk has been used daily stock price crash. The results of the estimation indicate a interaction negative and significant relationship between the voluntary disclosure of information and the Stock price crash risk in Tehran Stock Exchange. In other words the desire of managers to disclose bad news and to expedite the reporting of good news can lead to a Stock price crash risk. Also based on the results of this research there is no significant interaction relationship between voluntary disclosure of information and Stock price synchronicity in Tehran Stock Exchange.

The flow of information in the capital market is strategically important because it determines the path of investors' decisions. In this decision-making process, the managers of the companies can disclose timely and reliable information based on their cognitive and perceptual characteristics of capital market situations. This article aims to contribute to the capital market knowledge literature by presenting the framework of managers' inertia drivers in response to reliable disclosure of information. This study adopted mixed, both inductive and deductive approaches to develop an integrated framework, validate its practicability, and verify its effectiveness in selected firms listed on the Tehran Stock Exchange, respectively. In developing the framework and implementation procedure, the study employed a systematic screening data collection (qualitative) approach to review the managers' inertia drivers. Then, in this study's second phase, the Interpretive Rating Process (IRP) and Fuzzy Reference System are used to develop the framework of managers' inertia drivers in response to reliable disclosure of information. The study's results in the qualitative part indicate the determination of 8 driving areas of managers' inertia in the reliable disclosure of information. On the other hand, the quantitative section results showed that managers' overconfidence and excitability are the most influential fields in stimulating managers' inertia in the timely disclosure of information. Based on the results, it was determined that the excitability of managers' overconfidence in creating inertia causes managers' subjective estimates to cause exclusivity in information disclosure.

The results of experimental research on the relationship between information disclosure and risk premium have been somewhat contradictory. The purpose of this study is to investigate the effect of voluntary disclosure of information on risk premium based company characteristics in each of the periods of boom and bust of the capital market. In order to measure the variable of voluntary disclosure of information, the criteria of timeliness, bias and accuracy of midterm and annual earnings forecasts of the company have been used. To determine the time periods of capital market boom and bust, the Hudrick-Praskat filter was used and to test the hypotheses, the information of 130 companies listed on the Tehran Stock Exchange, between 2010 and 2018, and multiple regression model has been used. The results show that voluntary disclosure of information, for the measurements of timeliness and bias of midterm and annual earnings forecasts, positively and significantly and for the measurement of accuracy of midterm earnings forecast, negatively and significantly on risk premium based company characteristics are effective. Also, research results shows that the boom and bust of the capital market is a factor influencing the relationship between the timeliness measurement of midterm earnings forecast and accuracy of annual earnings forecast and risk premium based company characteristics. Also, the relationship expressed for different criteria for measuring voluntary disclosure of information is different.

Disclosure of information in the capital market affects stock prices. The reaction of investors to the gradual and continuous disclosure of information or to the immediate and discrete disclosure of information can have a different effect on the stock price. In addition, the existence of a momentum strategy in the capital market and its combination with discrete disclosure of information can increase these effects. Therefore, the purpose of this study is to investigate the effect of momentum and information discreteness on the excess stock return. The sampling method in this research is the systematic method of elimination and research period from 2010 to 2018. We select of 104 the companies and the method used to estimate the model of multivariate regression method. The results of the research showed that the momentum is effect the on the excess stock return. Therefore, investors can gain returns in the Iranian capital market by implementing a momentum strategy. Also, the results showed that the information discreteness is effect on the excess stock return. Therefore, investors can make higher returns by choosing companies whose information is disclosed immediately and discretely. In addition, the results showed that the combine of momentum and information discreteness have effect on the excess stock return. investors can achieve higher returns by choosing companies based on a combination of momentum strategy and information discreteness. Overall, the results showed that the information discreteness was added to the asset pricing models in addition to the variables of the Fama and French three-factor model.