Companies' voluntary disclosure is one of the most important management tools to convey information about the financial performance to investors, creditors and other stakeholders. One of the important reasons of the request for disclosure of information is agency problem and asymmetry of information. This study aims to examine value relevance of voluntary disclosure using models of Olson (1995), Easton and Harris (1991) and the value of firms with regard to the effect of endogeneity of voluntary disclosure variable. For this purpose, the voluntary disclosure index was calculated and tested for 146 companies listed in Tehran Stock Exchange during the period 1388-1392 using content analysis method and the same weighting approach. The results of this research reveal that companies' voluntary disclosure is used in their decision-making and valuation of companies. The results from the study of non-linearity in the relation between voluntary disclosure and firm value confirm the positive significant effect of enhanced voluntary disclosure levels on the value of firms.

The accounting information currently assimiliated by firms is not wholly adequate for decision makers, and additional information regarding risks is required. This study explores the characteristics of risk disclosures in annual reports of companies listed in Tehran Stock Exchange. The factors affecting risk disclosures are also explored. To achieve the preceding objectives, the annual reports of 275 firm- year over the period of 2009 to 2013 were studied based on the content analysis and the characteristics of risk related information were determined accordingly. Data collected by content analysis was examined using Comparison Tests. The result showed that companies were significantly disclosure back-ward looking rather than forward-looking information and qualitative rather than quantitative information about risk, and they were disclosing risk sources rather than risk managements. Furtheremoe, the result indicated that firm size and leverage Posit a significant positive relationship with corporate risk disclosure, but market risk of the firms exhibits a significant negative relationship with corporate risk.

The legal systems are not the same as regard to the duty of pre-contractual disclosure. The general principle in civil law is that the negotiating party must proffer the information in his possession which is material as to the other party’s decision. But in common law does not accept any general duty to disclosure in pre-contractual negotiations. According to this system, during negotiations a party may play his cards close to his chest and hold back information even if he is aware that knowledge of the facts would deter the other side from entering into the contract. The pre-contractual duty to disclosure is favorable in Islamic law but not generally known as a duty In Iranian legal system except in some particular cases.

This paper studies management bonus and disclosure quality, using historical data of firms listed in the Tehran Stock Exchange during the period from 2010 to 2014. The empirical evidence from other countries shows a significant positive correlation between management bonus and disclosure quality. To test the hypotheses the multivariate regression with panel data is used. The results of the first hypothesis test suggest that there is a significant negative relation between the cash bonus payment and disclosure quality. The results of the second hypothesis test suggest that there is a significant negative relation between non-cash bonus payment and disclosure quality too. The findings of the research hypotheses confirm moral hazard hypothesis of possibility for mismanagement to get more bonus.