This paper studies the government spending multiplier in the presence of the cost channel of the nominal interest rate. I find that the spending multiplier of normal times declines markedly when this channel is introduced. The rise in government spending leads to a rise in the nominal interest rate and, with the cost channel, to a rise in the marginal cost and inflation. In turn, this leads to a bigger rise in the nominal interest rate and the expected real interest rate, hence a lower multiplier, than in a model that abstracts from the cost channel. On the other hand, in a liquidity trap, the cost channel makes the spending multiplier larger. Therefore, by ignoring the cost channel, the spending multiplier is overestimated in normal times and underestimated during liquidity trap episodes. Since liquidity traps are rare, however, the spending multiplier is mostly lower than in previous estimates.

In this paper, I examine the role of government spending persistence on fiscal multipliers at the zero lower bound (ZLB) in a more realistic environment while keeping the model simple enough to identify mechanisms driving the result. In particular, I build on a standard dynamic New Keynesian (DNK) model with an occasionally binding ZLB and Rotemberg pricing with rebates, where the probability of hitting the ZLB and the government purchase shock are in line with US data. Moreover, I compute the multiplier in a state that mimics the Great Recession. The main findings of the paper are as follows: (1) the multiplier is non-monotonic in the persistence of government spending while the economy is at the ZLB; (2) given the persistence estimated from US data, the multiplier is 1.25; and (3) in the framework with perfect foresight or with aggregate resource cost for adjusting prices, the multiplier is around 1 or less.

There are suggestions that increased uncertainty makes fiscal policy temporarily less effective. In this paper, I examine the relationship between business uncertainty and fiscal policy effectiveness in Germany. I use measures of business uncertainty that are derived from the firm-level data of the Ifo Business Climate Survey and interact them with the parameters of a structural vector autoregression to produce state-dependent spending multipliers. The impact of increased uncertainty on the spending multiplier is generally small and often statistically not significant in the short run. By contrast, I obtain a significant positive impact on the long-run multiplier. These baseline results are supported by a variety of robustness checks and specifications.