Estimating Elasticity of Government Revenue w.r.t to Statutory Tariffs

Custom income is about 20% of Iran’s tax income. Is there a one to one relation between government’s revenue and statutory tax rates? This study assesses the elasticity of government custom revenue with respect to statutory tariff rates, also referred to as the slope of Laffer curve. We also estimate the elasticity of realized tariff rate and the legal imports. The data is from Iran’s custom and the World Bank (WITS). The final data include import values in rial and dollar, weight, statutory and realized tariff rates, from 2007 to 2016. We use fixed effect regressions which captures fixed characteristics of each observation, disaggregated into 6 digits of HS code. Results show that the eleasticty of government income with respect to statutory tariffs is 40 percent. The remaining part (60 percent) is neutralized due to the increase in tax avoidance and evasion. The elasticity of exemptions is estimated equal to about 50 percent and the legal import’s elasticity is about 20 percent. The latter contains both the demand reduction (Leffer effect) and the increase in evasion. Findings are robust to different tests, and indicate a substantial loophole between tariff setting and revenue earning. While reducing in illegal section requires fundamental reforms, the exemptions can be reduced by reconsidering in legal provisions.