This study inves tigates the effects of TAX avoidance on TAX risk using a conceptual and statistical modeling of TAX risk measuring, BASEd on uncertainty indicator. The sample consists of 114 firms in the period from 2009 to 2016. TAX avoidance is measured by the effective TAX rate (ETR). Also TAX risk is measured using the EGARCH model and defined as the instability of TAX status over time. The research findings show that there is a significant negative relation between effective TAX rate and instability of the TAX status, which means that firms with lower effective TAX rate have instability of TAX status over time. On the other hand, findings indicate an increase in TAX difference in event of effective TAX rate decreases. According to findings, one of the consequences of TAX avoidance is increases of TAX risk. The findings provide new evidence about the consequences of CORPORATE TAX avoidance. These findings can be used to assess the TAX risk of firms BASEd on their effective TAX rate. Also the findings suggest investors and managements to consider the consequences of CORPORATE TAX decreases.

Effective TAX rate is one of the most important TAX efficiency criteria in TAX literature. Moreover, TAX system efficiency is usually measured by bilateral comparison between administrative costs and effective TAX rate. By examination and estimation of effective TAX rate, TAX authorities are able to increase TAX justice and investigate TAX burden on TAXpayers. Effective TAX rate could be an instrument to direct capitals, as well as its wide using in policy-making and economic decisions. In present paper an attempt is made to estimate effective TAX rate in business and CORPORATE income TAX. The results show that effective CORPORATE TAX rate had an increasing trend from 6.08 to 11.59 during 2001 to 2008 while effective business TAX rate has been decreased by 2.1 to 1.3 between 2001 and 2007.

Separating management jobs and ownership imposes agency problem among different groups of stakholders. CORPORATE Governance in organizations is a mechanism for mitigating the problem. Also, in different organizations, TAX computation and payment is viewed as an interesting subject. Investors demand for increasing earnings and firm’s value that make them to reduce the amount of TAXes and may lead to less payment of TAXs. Nevertheless, the public ask for companies’ recognition of fair amount of TAXes and companies’ regular payments of TAXes. In this environment, CORPORATE governance may create balance between the public’s and companies’ interests.This study investigates the relationships between some indexes of CORPORATE governance, such as institutional ownership, board independency and board size, and the issue of TAX avoidance. For this purpose, we studied 146 companies listed in the Tehran Stock Exchange, during 2001-2012. The results from 1227 firm-year data within an unbalanced panel data model showed no significant relationship between CORPORATE governance and TAX avoidance. Additionally, findings showed a negative significant relationship between control variables of profitability and firm’ size, and a positive significant relationship between TAX auditing and TAX avoidance.

The imposition of more economic sanctions on the state and the reduction of oil incomes in recent years have directed attention towards TAX and collection of more TAX revenues; therefore, the recognition of the determinants of TAX evasion is necessary. The decision of TAXpayers for TAX compliance or evasion is a function of multiple variables. The “ culture” variable is a determinant of the TAX payer’ s behavior for paying or evading the payment of the TAX; and accordingly, the present work is to analyze the link/s existing between organizational culture and TAX evasion. In terms of purpose, the present study is applied, methodologically, it is descriptive (survey), and concerning the relations between its variables, it is correlational. The companies admitted to Tehran Stock Exchange make the statistical society of this research, and eventually, 110 companies meeting some specific criteria were chosen in this regard. The data collection tool included Hofstede’ s Standard Questionnaire (1980) on the cultural organization and Craw Standard Questionnaire for TAX evasion (1994) devised BASEd on Likert five-value scale. Once the reliability and validity of the questionnaire were confirmed, it was handed to the top heads of the related companies and the required data were collected. The research data were analyzed using structural equations modelling. The results of the study suggest that organizational culture has a significant impact on TAX evasion. Uncertainty avoidance and big power distance lead to the increase of TAX evasion, nonetheless, democracy lowers TAX evasion.

A delay in finalizing a company's TAX file causes a decrease in the real value of the government's TAX revenues, an increase in the cost of TAX collection, and the destruction of the business environment for companies. Therefore, in this article, the factors influencing this delay were investigated by using the data of 45 companies from the three petrochemical, chemical and food industries of Iran and analyzing their TAX files during the financial years of 2015 to 2015 using the combined data regression method. The results show that 62% of the cases were decided in authorities outside the TAX organization and the average time for the companies' TAX cases to be decided was more than 4 years. The results show that the size of the company, TAX complexity, the difference in the diagnostic-expressive TAX rate and the change in the TAX laws have a positive and significant effect on the delay in the finalization of the TAX in all companies, but the results are somewhat different in the petrochemical industry, chemical industry and food industry

In this paper, optimal TAX rates for real and legal entity income TAXes have been estimated. Optimal TAXation means optimal maximization of total utility functions of entities with regard to the budget constraint and a constraint wherein the entities make their choices of labor supply taking into consideration the relationship between labor and income. The foundation of our estimation has been Diamond’s model (1998) which is itself an extended form of Diamond and Myrrless’s model (1971). This model is, in its turn, an adaptation of Saez’s model, an important optimal TAXation model. The statistic population being used for the calculation includes real entities in Tehran and legal entities in Tehran and Kermanshah cities. In order to cover the fairness of income distribution, the statistical data has been classified in terms of income deciles, and Gini coefficient was calculated as an indicator of income distribution variance. Then, an appropriate model which is assumed to have the best impact on the decrease of the Gini coefficient has been selected. Finally, through the application of the selected model and taking into account different levels labor force elasticity (for real entities) and services supply elasticity (for legal entities), the optimal TAX rates have been calculated. The results obtained indicate that in the Iranian TAX system, the application of new rates would lead to a better distribution of income as well as an increase of 150% in the government TAX revenues. Moreover, the calculated rates are able to be interpreted on the basis of an extended formulation of Laffer’s curve.