The fiscal year begins on March 21 and ends on March 20 of the next year. The Ministry of Finance and Economic Affairs is the government agency authorized to levy and collect taxes. In 2008, about 55% of the government's budget came from oil and natural gas revenues, the rest from taxes and fees.[1] An estimated 50 percent of Iran's GDP was exempt from taxes in FY 2004.[2] There are virtually millions of people who do not pay taxes in Iran and hence operate outside the formal economy.[3][4]

As part of the Iranian Economic Reform Plan, the government has proposed income tax increases on traders in gold, steel, fabrics and other sectors, prompting several work stoppages by merchants.[5] In 2011, the government announced that during the second phase of the economic reform plan, it aims to increase tax revenues, simplify tax calculation method, introduce double taxation, mechanize tax system, regulate tax exemptions and prevent tax evasion.[6