تحلیل اثر رانت نفت بر فرار مالیاتی در ایران: با تمرکز بر نرخ ارز

نفت خام و رانت حاصل از آن برای کشورهای نفتی می‎تواند همراه با مزایا و معایبی باشد. مطالعات بسیاری اثر رانت نفتی را بر متغیرهای مختلفی همچون رشد اقتصادی، تورم و توسعه مالی مورد بررسی قرار داده‎اند. در این میان نقش احتمالی رانت نفتی بر فرار مالیاتی با تمرکز بر نرخ ارز موضوعی بوده است که به نظر در مطالعات مورد توجه نویسندگان قرار نگرفته است. بدین منظور در پژوهش حاضر ابتدا اندازه نسبی فرار مالیاتی با استفاده از روش شاخص چندگانه-علل چندگانه محاسبه شد که حاکی از میانگین 8/1 درصدی در اقتصاد ایران است. سپس با استفاده از رهیافت خودرگرسیونی با وقفه‌های توزیعی، اثر رانت نفتی بر فرار مالیاتی با توجه به نقش نرخ ارز در بازه زمانی 1359 تا 1401 بررسی و آزمون شد. نتایج برآوردها در بلندمدت نشان می‎دهد که رانت نفتی با اثری مثبت بر فرار مالیاتی همراه است و اثرگذاری مثبت رانت نفتی بر فرار مالیاتی، متاثر از میزان نرخ ارز حقیقی است. به‌نحوی‌که در مقادیر بالاتر نرخ ارز، اندازه اثرگذاری مثبت رانت نفتی بر فرار مالیاتی در ایران تشدید می‌شود. همچنین باز بودن تجارت با اثری منفی و بیکاری و تورم با اثری مثبت بر فرار مالیاتی اثرگذارند.

analysis of the effect of oil rent on tax evasion in iran: focusing on the exchange rate

crude oil and its rent can have advantages and disadvantages for oil-rich countries. many studies have investigated the effect of oil rent on various variables such as economic growth, inflation and financial development. meanwhile, the possible role of oil rent on tax evasion by focusing on the exchange rate has been a topic that has not been considered by the authors in the studies. for this purpose, in the current research, the relative size of tax evasion was first calculated using the multiple indicators-multiple causes (mimic) method, which indicates an average of 8.1% in iran's economy. then, using the ardl approach, the effect of oil rent on tax evasion was investigated and tested with regard to the role of the exchange rate in the period from 1980 to 2022. the results of long-run estimates show that oil rent has a positive effect on tax evasion and the positive effect of oil rent on tax evasion is affected by the real exchange rate. in such a way that in higher values ​​of the exchange rate, the size of the positive effect of oil rent on tax evasion in iran is intensified. also, the trade openness has a negative effect and unemployment and inflation have a positive effect on tax evasion.introduction many governments face challenges in combating tax evasion. the government encounters significant economic consequences as a result of losing tax revenue (cerqueti & coppier, 2011), as it becomes unable to provide public services and other facilities that benefit society (johnson et al., 2000). according to quintin (2008), industrialized countries have more effective judicial systems and better regulatory enforcement than developing countries, which explains why the shadow economy is relatively small in wealthy nations .the abundance of natural resources in resource-rich countries has had varying and sometimes contradictory effects on their economic development processes. since the first oil shock in 1973, iran’s economic performance has been closely linked to its natural resource wealth. additionally, a review of the historical trend of oil prices shows significant volatility, making it an unreliable source for financing government expenditures. according to theoretical foundations, natural resource rents should enhance the economic and social welfare of local communities. countries with rich natural resource reserves are often considered fortunate because these resources are valuable capital that can be transformed into essential infrastructure, fostering a country’s economic development and progress .one channel of transmission is the negative effects of resource rent dependency on the government’s tax capacity and its willingness to reform the tax system. lower taxes in response to increased resource rents may be an optimal response from an efficiency standpoint, as it allows governments to shift their budgets away from distortionary taxes. on the other hand, this study can be aligned with the concept of the resource curse, examining the short- and long-term negative effects of resource rents on the government’s capacity for taxation. in examining the long-run negative effects of dependency on resource rents on tax administration, besley and persson (2011) acknowledged that greater reliance on resource rents directly flowing into government budgets might mean lower market revenues. this results in a smaller tax base, which then reduces incentives to invest in legal capacity to support markets. consequently, this leads to capital shifting toward informal activities and increases tax evasion. it is worth noting that one factor influencing the relationship between oil rents and tax evasion is the exchange rate, as it can affect oil prices and thus oil rents through its fluctuations. since the exchange rate acts as a link between domestic and international prices, it is given particular attention in economic studies. given the significant role of oil rents in the economies of oil-exporting countries, previous domestic and international studies have sought to examine the impact of oil rents on various economic variables such as economic growth, financial development, and inflation. this study aims to examine the role of oil rents on tax evasion in iran while considering the role of the exchange rate. accordingly, this research seeks to answer two questions: first, what is the relationship between oil rents and tax evasion in iran? second, how does the exchange rate influence this relationship? in this study, alongside calculating the relative size of tax evasion using the multiple indicators-multiple causes (mimic) method during the period 1980–2022, efforts have been made to analyze the effect of oil rents on tax evasion with an emphasis on the role of exchange rates. methods and material first, the size of tax evasion (as a percentage of gdp) was calculated using the mimic method. then, as mentioned in the introduction, the main objective of this study is to analyze and examine the effect of oil rents on tax evasion in iran, considering the role of the exchange rate. given the potential delay in the impact of explanatory variables on tax evasion, as well as accounting for the influence of other factors affecting tax evasion, the autoregressive distributed lag (ardl) approach is employed . it is worth noting that in this study, tax evasion is considered the dependent variable, while oil rents, the exchange rate (in interaction with oil rents), trade openness, unemployment, and inflation are included as explanatory variables . results and discussion the results of the estimated model in the long run indicate that oil rents have a positive effect on tax evasion, and the magnitude of this positive impact is influenced by the level of the real exchange rate. specifically, at higher levels of the exchange rate, the positive effect of oil rents on tax evasion in iran is amplified. additionally, trade openness has a negative impact on tax evasion, while unemployment and inflation exert positive effects. regarding the inverse relationship between oil rents and tax evasion in iran, it can be stated that in resource-rich countries (including oil-rich nations like iran), governments are not reliant on taxation for financing their expenditures. instead, they fund their budgets through revenues generated from oil. oil rents and their fluctuations have had a positive effect on inflation and a negative effect on production in iran. considering the positive impact of inflation on tax evasion and the decline in production, an increase in the ratio of tax evasion to production is expected. as for the role of the exchange rate as an amplifying factor in the relationship between oil rents and tax evasion, several channels can be considered, one of the most fundamental being the uncertainty caused by exchange rate growth and fluctuations in iran. evidently, if exchange rate growth and volatility are high and lead to increased uncertainty, tax revenues decrease while tax evasion rises. conclusion the findings of this study indicate an adverse (positive) impact of oil rents on tax evasion in iran. to address this issue and reduce the scale of tax evasion in the country, policymakers are advised to prioritize strategies such as preventing unplanned inflows of oil rents into the economy, utilizing sovereign wealth funds, or pursuing national development initiatives. furthermore, given the amplifying role of the exchange rate in the relationship between oil rents and tax evasion, it is recommended that the central bank intensify efforts to stabilize the real exchange rate to minimize uncertainty imposed on commercial actors.