Lunch Seminar 2026-27

The increased global mobility of capital and labour poses a number of challenges to national tax systems: intricate global structures to hide personal wealth from the eyes of tax administrators and regulators, conflicts about the international allocation of taxing rights, and a fast-evolving international tax policy landscape. The seminar focuses on the topic of taxation in the global economy and aims to bring together international junior and senior researchers working on international taxation, tax avoidance and evasion, tax competition, tax harmonisation and related topics. Presentations can be polished papers or work in progress. The aim is to learn from each other and to discuss in a friendly atmosphere.

The seminar takes place at Paris School of Economics and via Zoom.

Sign up for the seminar mailing list here.

If you would like to book a private time slot to meet the speaker, please email Léo Czajka leo.czajka@psemail.eu specifying which session.

2026-27 Calendar

Friday 9 October 2026 12:00-13:00 │ R1-15

• Valentin Marchal (Sciences Po): A Scrooge McDuck Theory of Wealth Dynamics

Abstract: Can the rise in the wealth-to-output ratio observed in advanced economies over recent decades be explained by an increase in top income inequality? Recent contributions that advance this interpretation struggle to account for the fact that the increase in wealth was driven by asset prices, rather than capital accumulation. This paper shows that these stylized facts can be reconciled in the presence of insatiable preferences for wealth. Such preferences induce a cap on optimal consumption, which is more likely to become binding when income inequality is large. When it does, top-income agents accumulate diverging wealth over time while keeping their consumption bounded. This consumption-saving behavior supports the existence of a uniquely determined rational bubble, which grows at a rate that exceeds that of the economy. The bubble crowds out investment, while its diverging price sustains a permanent rise in wealth inequality. In this environment, wealth and capital income taxes are not equivalent, but both can shift the equilibrium from bubbly to non-bubbly—thus being potentially redistributive and growth-enhancing. A quantitative exercise suggests that a 1.5 percent wealth tax in the U.S. would raise capital by 5 percent over 30 years.

Friday 16 October 2026 12:00-13:00 │ R1-15

• Elena Herold (ifo Institute)

Friday 13 November 2026 12:00-13:00 │ R1-15

• Javier Soria-Espin (PSE )

Friday 27 November 2026 12:00-13:00 │ R1-15

• Franziska Disslbacher (WU Vienna University of Economics and Business)

Friday 11 December 2026 12:00-13:00 │ R1-15

• Antonella Bancalari (IFS – Institute for Fiscal Studies)

Past Seminars

Friday 25 September 2026 12:00-13:00 │ R1-15

• Christos Kotsogiannis (University of Exeter and CESifo): VAT Threshold and Organisational Splitting with Kenneth Tester

Abstract: This paper studies the optimal VAT registration threshold when firms can artificially split their activities across multiple legal entities. Rather than suppressing output to remain below the threshold, firms may preserve their productive scale by splitting activity across sub-threshold entities, albeit at an organisational cost. Introducing this additional behavioural margin changes the government’s threshold design problem: a higher threshold can reduce both output distortions and inefficient organisational fragmentation, but at the cost of narrowing the formal tax base. A key feature of the analysis is that the optimal policy depends critically on enforcement capacity. In the numerical examples, weak enforcement raises the optimal threshold relative to the no-splitting benchmark. Intermediate enforcement can lower it, while stronger enforcement eliminates splitting at the optimum and restores the benchmark allocation. The analysis highlights the importance of accounting for organisational responses when designing VAT registration thresholds.

Friday 11 September 2026 12:00-13:00 │ R1-15

• Louis de la Chapelle (CREST): Investment Tax Incentives and the Price of Capital Goods: Consequences for Policy Effectiveness and Incidence

Abstract: Investment tax incentives are common and ambitious policies, yet we know surprisingly little about their consequences for the prices of the capital goods they subsidize. We study these consequences in the case of a temporary investment tax incentive in France, which mechanically reduced the user cost of capital by 13% between 2015 and 2017. Using firm and product-level data on production and prices, we show that the policy raised the pre-tax price of eligible capital goods by 2.6% on average. We draw three implications for the effectiveness and the incidence of investment tax incentives. First, measuring investment responses in value terms may overstate physical capital expansion, by a third in our context. Second, the price effects that mediate the policy are context-dependent, which questions the external validity of any given estimate: we find them concentrated in less competitive and in capacity-constrained product categories, and absent elsewhere. Third, capital producers captured at least 30% of the benefits of this investment tax incentive.

Friday 4 September 2026 12:00-13:00 │ R1-15

• Juan Rios Rivera (PUC-Rio)

This project is funded by the European Union.