The impact of oil shocks on government expenditure components and tax revenues in Iran

In this article, the effects of oil revenue shocks on the constituent components of the government's expenditures during the period of 1990/04 to 2018/04 and tax revenues during the period of 1993/01 to 2018/04 in Iran are investigated. In this regard, in order to consider the structural instability in the parameters, time-varying parameter generalized vector autoregression (TVP-VAR) models have been used. Based on the results obtained from the first model of the research, the impact of oil income impulses on defense expenditure is estimated to be positive. Although the said effect quickly disappears in the later periods. Therefore, it can be said that the impact of oil revenue impulses on government defense expenses is temporary. Also, the effect of impulses on economic and social affairs expenditures is estimated to be positive. The impact of oil income impulses on public affairs expenses was initially positive, but it gradually decreased and reversed in later periods. The results of the second model of the research, in which the impact of oil revenue shocks on direct and indirect tax revenues is investigated. The impact of oil revenue impulses on direct tax revenues from the positive range is quickly placed in the negative range. On the opposite point, the impact of oil income impulses on indirect taxes starts from the negative range and then quickly moves to the positive range. Also, the impact of oil revenue impulses on indirect taxes can be considered positive.