Publications des chercheurs de PSE

Historically, large changes in U.S. government spending induced fiscal efforts that were not all alike, with some using more progressive taxes than others. We develop a heterogeneous-agent New Keynesian model to analyse how the distribution of taxes across households shapes spending multipliers. The model yields empirically realistic distributions in marginal propensities to consume and labour elasticities, which result in lower responsiveness to tax changes for higher-income earners. In turn, multipliers are larger when spending is financed with higher tax progressivity—that is, when the tax burden falls more heavily on higher-income earners. This result is historically material. We estimate that, on average, tax rates increased more for top-income than for bottom-income earners after a spending shock. Thus, the typical U.S. spending shock was financed with higher tax progressivity. We further exploit the historical variation in the financing of spending to estimate progressivity-dependent multipliers, which we find consistent with the model.

The invasion of Ukraine by Russia in February 2022 prompted numerous countries to impose economic sanctions against Russia. In the months following the onset of the conflict, coalitions of nations collaboratively devised a set of measures aimed at restricting trade with Russia. Additionally, assets belonging to Russian individuals or companies were frozen. The scale of these sanctions has been unparalleled, marking a historic moment not witnessed for decades. This pertains not only to the extent and variety of economic actions taken against Russia but also to the aspect of implementing such actions against a nation of Russia's size and geopolitical importance. To evaluate the impact of sanctions on the Russian economy, analysts examined the exchange rate, which has the advantage of being available in real time. Initially, after the sanctions were imposed, the Ruble experienced depreciation, prompting several analysts to assert the effectiveness of the sanctions. However, a few months later, the Ruble began to appreciate, eventually surpassing its pre-war level in late spring 2022 and maintaining this elevated position for several months. This rebound in the Russian currency raised inquiries about the correlation between sanctions and exchange rates: is it inevitable for the currency to depreciate after sanctions, and if so, why?

This paper analyzes optimal fiscal policy with ambiguity aversion and endogenous government spending. We show that, without ambiguity, optimal surplus-to-output ratios are acyclical and that there is no rationale for either reduction or further accumulation of public debt. In contrast, ambiguity about the cycle can generate optimally policies that resemble "austerity" measures. Optimal policy prescribes higher taxes in adverse times and front-loaded fiscal consolidations that lead to a balanced primary budget in the long-run. This is the case when interest rates are sufficiently responsive to cyclical shocks, that is, when the intertemporal elasticity of substitution is sufficiently low.

We study the optimal joint design of targeted transfers and progressive income taxes. We develop a simple analytical model and demonstrate an optimally negative relation between transfers and income-tax progressivity, due to both efficiency and redistribution concerns. That is, higher transfers should be financed with lower income-tax progressivity. We next quantify the optimal fiscal plan in a rich dynamic model calibrated to the U.S. economy. Transfers should be generous and financed with moderate income-tax progressivity. To redistribute while preserving efficiency, average tax-and-transfer rates should be more progressive than marginal rates. Transfers, even if lump-sum, precisely allow to disentangle average from marginal rates. Targeted transfers further implement non-monotonic marginal rates, but generate only modest additional gains relative to a lump-sum transfer. Quantitatively, the left tail of the income distribution determines the optimal size of the transfer, while the right tail drives the optimal income-tax progressivity.

We study the optimal design of means-tested transfers and progressive income taxes. In a simple analytical model, we show that adding a transfer to a log-linear tax induces welfare gains almost as large as in the second-best allocation. Transfers allow for more progressive average than marginal tax and transfer rates, achieving redistribution while preserving efficiency. In a rich dynamic model, we quantify the optimal fiscal plan. We use new flexible functions featuring targeted transfers and progressive income taxes, delivering a good empirical fit across the income distribution. Transfers should be larger than currently in the United States and financed with moderate income tax progressivity.