Consumption smoothing and shock persistence : optimal simple fiscal rules for commodity exporters

A common criticism of balanced budget fiscal rules is that they increase the consumption volatility of financially constrained households who are unable to smooth consumption. This paper evaluates the welfare consequences of simple fiscal rules in a model of a small commodity-exporting country with a share of financially constrained households, where fiscal policy takes the form of transfers. A main finding is that balanced budget rules for commodity revenues often outperform more sophisticated fiscal rules where commodity revenues are saved in a Sovereign Wealth Fund (SWF). Because commodity price shocks are typically highly persistent, the households'current income is close to their permanent income, making balanced budget rules close to optimal. For commodities like oil, where price shocks are highly persistent, it is optimal to spend more than two-thirds of windfall revenues in times of high prices, and in some cases even spend the entire windfall. But for commodities where price shocks are less persistent, like bananas or sugar, the optimal rule involves spending less than half of above-average commodity revenues (with the rest saved in a SWF). It is also best to respond counter-cyclically to non-resource GDP shocks, because those shocks are less persistent (and also affect households other income). The government does not have the ability to perfectly smooth constrained households? consumption without adversely affecting unconstrained households.