1- University of Tehran , s.reza.nakhli65@ut.ac.ir
2- Shahid Beheshti University
2- Shahid Beheshti University
Abstract: (14 Views)
The aim of this research is to simulate and evaluate the effects of government fiscal policies within the framework of personal income tax, focusing on tax rate and basic exemption shocks, in the Iranian economy. To this end, a micro-founded dynamic stochastic general equilibrium model is designed, incorporating two groups of households: Ricardian and non-Ricardian. The model is estimated using quarterly data from the Iranian economy during the period 1991 to 2023, employing the Bayesian method. Simulation results indicate that an increase in the total income tax rate reduces the consumption of non-Ricardian households and, coupled with a decline in investment, leads to recessionary effects despite an improvement in tax revenues. Under conditions of tax exemption for government bonds, Ricardian households' propensity to purchase bonds increases, and the reduction in the government budget deficit is amplified. Furthermore, an increase in the basic exemption, if the bond yield rate is higher than the capital rental rate, strengthens demand for bonds and further reduces the budget deficit; conversely, when the capital rental rate is higher, resources are directed towards investment, and the recessionary effects of the policy are mitigated. Overall, the results suggest that adjusting the basic exemption is a more effective tool for improving government fiscal sustainability compared to increasing the tax rate.
Introduction
Sustainable financing of public expenditures is one of the fundamental challenges of economic policymaking, especially in developing economies. In macroeconomics literature, taxation is recognized as the most desirable tool for government resource provision due to its stable and non-inflationary nature, whereas extensive reliance on oil revenues or borrowing from the banking system is usually accompanied by macroeconomic instabilities and exacerbated inflation (Johnson et al., 2024). In this context, personal income tax, as one of the most comprehensive tax bases, plays a significant role in funding the government budget, improving the efficiency of the tax system, and enhancing fiscal sustainability (Wang & Chen, 2022). However, evidence suggests that in the Iranian economy, the share of this tax base is very limited compared to developed countries, and the country's tax system still suffers from structural weaknesses in covering personal incomes (Nasiri Aghdam & Razmi, 2015). Simultaneously, chronic budget deficits, dependence on unsustainable resources, and increasing income inequality have highlighted the necessity of reviewing tax policies (Fathollahi et al., 2023). Despite the importance of the issue, few studies have structurally and comprehensively examined the macroeconomic effects of personal income tax in the Iranian economy. Therefore, the aim of this research is to evaluate the effects of government fiscal policies within the framework of personal income tax on the dynamics of the Iranian macroeconomy and to investigate the consequences of changes in tools such as tax rates and basic exemptions on macroeconomic variables and government fiscal sustainability (Ahmadi et al., 2022).
Methods and Material
In this study, we employed a multifaceted approach to data collection, which included library research, documentary analysis, and the utilization of databases such as those provided by the Central Bank of the Islamic Republic of Iran and the World Bank (WDI). We developed a stochastic dynamic general equilibrium model tailored to the characteristics of the Iranian economy, covering the period from 1991 to 2023. To evaluate the study's hypotheses, we applied standard econometric methods, allowing us to assess the impact of impulses. It's important to note that the models were estimated within the Dynare programming environment, utilizing MATLAB software. This enhanced our ability to accurately interpret and present our findings.
Results and Discussion
The results showed that increasing the tax rate on total personal income reduces the consumption of Ricardian households and increases the consumption of non-Ricardian households. On the other hand, by reducing the amount of investment in non-Ricardian households, it will lead to a decrease in demand, a decrease in GDP and a decrease in the demand for production inputs, and consequently a decrease in total costs and inflation. In these circumstances, the government budget deficit will also decrease due to an increase in tax revenues in the short term, which will intensify in the long term due to the effects of recession and a decrease in tax revenues.
However, if the government exempts income from bonds from the inclusion of this tax, an increase in the aforementioned tax rate will cause a sharp decrease in the consumption of non-Ricardian households and a smaller decrease in consumption, a decrease in investment, and an increase in the purchase of bonds by Ricardian households, which will attract resources to bonds, making the government more open to reducing its budget deficit.
On the other hand, reducing the tax base exemption will cause a decrease in the taxable income of Ricardian households and a sharp decrease in the consumption of these households. Ricardian households reduce their consumption and try to increase their financial assets (investment and bonds) to earn future profits to compensate for lost income. As a rule, if the return on capital is higher, more resources are directed towards productive activities, which partially offsets the recessionary effects of reduced consumption and even allows for economic prosperity. On the other hand, if bonds have a more attractive return, more liquidity is directed towards the purchase of government bonds and helps reduce the budget deficit. Regarding the state of the government budget, the increase in tax revenues resulting from the reduction of exemptions will reduce the budget deficit, and if the tendency to purchase bonds is greater than investment, the reduction of the budget deficit will be intensified in the short term. However, if this policy leads to growth in investment and ultimately economic growth, it can increase government revenues and reduce the budget deficit in the long term by expanding the tax base.
Conclusion
The findings of this study suggest that tax policy design should be done carefully, taking into account the differential effects on different income groups. Increasing basic exemptions can be used as an effective tool to stimulate aggregate demand and improve the economic situation, while increasing tax rates without considering exemptions may have negative effects on economic growth.
Keywords: Fiscal policy, Personal Income Tax, Government Budget Deficit, Stochastic Dynamic General Equilibrium Model.
JEL Classification: E62, H24, H25, H26
Introduction
Sustainable financing of public expenditures is one of the fundamental challenges of economic policymaking, especially in developing economies. In macroeconomics literature, taxation is recognized as the most desirable tool for government resource provision due to its stable and non-inflationary nature, whereas extensive reliance on oil revenues or borrowing from the banking system is usually accompanied by macroeconomic instabilities and exacerbated inflation (Johnson et al., 2024). In this context, personal income tax, as one of the most comprehensive tax bases, plays a significant role in funding the government budget, improving the efficiency of the tax system, and enhancing fiscal sustainability (Wang & Chen, 2022). However, evidence suggests that in the Iranian economy, the share of this tax base is very limited compared to developed countries, and the country's tax system still suffers from structural weaknesses in covering personal incomes (Nasiri Aghdam & Razmi, 2015). Simultaneously, chronic budget deficits, dependence on unsustainable resources, and increasing income inequality have highlighted the necessity of reviewing tax policies (Fathollahi et al., 2023). Despite the importance of the issue, few studies have structurally and comprehensively examined the macroeconomic effects of personal income tax in the Iranian economy. Therefore, the aim of this research is to evaluate the effects of government fiscal policies within the framework of personal income tax on the dynamics of the Iranian macroeconomy and to investigate the consequences of changes in tools such as tax rates and basic exemptions on macroeconomic variables and government fiscal sustainability (Ahmadi et al., 2022).
Methods and Material
In this study, we employed a multifaceted approach to data collection, which included library research, documentary analysis, and the utilization of databases such as those provided by the Central Bank of the Islamic Republic of Iran and the World Bank (WDI). We developed a stochastic dynamic general equilibrium model tailored to the characteristics of the Iranian economy, covering the period from 1991 to 2023. To evaluate the study's hypotheses, we applied standard econometric methods, allowing us to assess the impact of impulses. It's important to note that the models were estimated within the Dynare programming environment, utilizing MATLAB software. This enhanced our ability to accurately interpret and present our findings.
Results and Discussion
The results showed that increasing the tax rate on total personal income reduces the consumption of Ricardian households and increases the consumption of non-Ricardian households. On the other hand, by reducing the amount of investment in non-Ricardian households, it will lead to a decrease in demand, a decrease in GDP and a decrease in the demand for production inputs, and consequently a decrease in total costs and inflation. In these circumstances, the government budget deficit will also decrease due to an increase in tax revenues in the short term, which will intensify in the long term due to the effects of recession and a decrease in tax revenues.
However, if the government exempts income from bonds from the inclusion of this tax, an increase in the aforementioned tax rate will cause a sharp decrease in the consumption of non-Ricardian households and a smaller decrease in consumption, a decrease in investment, and an increase in the purchase of bonds by Ricardian households, which will attract resources to bonds, making the government more open to reducing its budget deficit.
On the other hand, reducing the tax base exemption will cause a decrease in the taxable income of Ricardian households and a sharp decrease in the consumption of these households. Ricardian households reduce their consumption and try to increase their financial assets (investment and bonds) to earn future profits to compensate for lost income. As a rule, if the return on capital is higher, more resources are directed towards productive activities, which partially offsets the recessionary effects of reduced consumption and even allows for economic prosperity. On the other hand, if bonds have a more attractive return, more liquidity is directed towards the purchase of government bonds and helps reduce the budget deficit. Regarding the state of the government budget, the increase in tax revenues resulting from the reduction of exemptions will reduce the budget deficit, and if the tendency to purchase bonds is greater than investment, the reduction of the budget deficit will be intensified in the short term. However, if this policy leads to growth in investment and ultimately economic growth, it can increase government revenues and reduce the budget deficit in the long term by expanding the tax base.
Conclusion
The findings of this study suggest that tax policy design should be done carefully, taking into account the differential effects on different income groups. Increasing basic exemptions can be used as an effective tool to stimulate aggregate demand and improve the economic situation, while increasing tax rates without considering exemptions may have negative effects on economic growth.
Keywords: Fiscal policy, Personal Income Tax, Government Budget Deficit, Stochastic Dynamic General Equilibrium Model.
JEL Classification: E62, H24, H25, H26
Keywords: Fiscal policy, Personal Income Tax, Government Budget Deficit, Stochastic Dynamic General Equilibrium Model.
Type of Study: Research |
Subject:
Economic
Received: 2025/05/7 | Accepted: 2026/09/1 | Published: 2026/09/1
Received: 2025/05/7 | Accepted: 2026/09/1 | Published: 2026/09/1
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