Gabriel Zucman

Gabriel Zucman (born 1986) is a French economist specializing in public economics, particularly tax evasion, corporate profit shifting, and the measurement of income and wealth inequality. He earned his PhD from the Paris School of Economics in 2013 under Thomas Piketty's supervision, held a position at the London School of Economics from 2014 to 2015, and joined the University of California, Berkeley in 2015 as an assistant professor, becoming associate professor in 2019, and in 2023 became a professor at the Paris School of Economics; at Berkeley he also serves as Summer Research Professor and Summer School Director for the James M. and Cathleen D. Stone Center on Wealth and Income Inequality. Zucman's research estimates that approximately 8% of global household financial wealth is held in tax havens and that multinationals shift 36% of their profits to low-tax jurisdictions. Collaborating with Emmanuel Saez and Thomas Piketty, he co-developed Distributional National Accounts, which report that U.S. pre-tax income for the top 1% grew by 204% from 1980 to 2014, compared to 1% for the bottom 50%. Alternative estimates using the same tax data, notably Auten and Splinter (Journal of Political Economy, 2024), find smaller pretax increases and little change in after-tax top shares. In a study using leaked customer lists from offshore financial institutions, including the Panama Papers, matched to Scandinavian wealth records, Annette Alstadsæter, Niels Johannesen and Zucman (American Economic Review, 2019) estimated that the richest 0.01% of households evade about 25% of their taxes, compared with less than 5% detected in random audits. In 2023, Zucman received the John Bates Clark Medal from the American Economic Association for these contributions to public economics and inequality analysis. He also directs the EU Tax Observatory and co-directs the World Inequality Lab. His proposals and findings have been contested: Lawrence Summers and Natasha Sarin argued that his U.S. wealth-tax revenue estimates were greatly overstated, Phillip Magness and David Splinter disputed his conclusion that the richest Americans pay lower tax rates than the bottom half, and in France the National Assembly in October 2025 and the Senate in June and November 2025 rejected the proposed "Zucman tax."

Background

Early life

Gabriel Zucman was born in Paris, France, in 1986. He is the son of two French physicians; his mother works as an immunology researcher, while his father treats patients with HIV.

Zucman was raised in a well-off family in Paris. Little additional public information exists regarding his childhood or formative influences prior to formal education, as Zucman maintains a private personal profile.

Education

Zucman attended the École Normale Supérieure Paris-Saclay, a selective French grande école, from 2005 to 2010, where he received training in economics and related fields as part of the institution's rigorous curriculum integrating advanced undergraduate and graduate-level studies.

In 2008, he earned a Master of Science (MSc) in Economic Policy Analysis from the Paris School of Economics (PSE), focusing on analytical tools for public policy evaluation.

From 2009 to 2013, Zucman completed a PhD in Economics at PSE, with his dissertation addressing international financial flows and their implications for national accounts, under the supervision of faculty affiliated with PSE's partner institutions including the École des Hautes Études en Sciences Sociales (EHESS).

Professional career

Initial appointments

Following completion of his PhD in economics from the Paris School of Economics in 2013, before the LSE appointment, he had spent 2013–2014 as a postdoctoral scholar at the University of California, Berkeley, invited by Emmanuel Saez to collaborate on empirical studies of taxation and inequality. He then was appointed Assistant Professor of Economics at the London School of Economics, serving in that role from 2014 to 2015. In this position, he focused on research related to international tax evasion and wealth inequality, building on his doctoral work supervised by Thomas Piketty. This postdoc facilitated his integration into Berkeley's economics department, where he joined the faculty as an assistant professor in 2015.

Current positions and affiliations

Gabriel Zucman is a Professor of Economics at the Paris School of Economics (PSE) and École Normale Supérieure – PSL, a position he has held since 2023. He also serves as Summer Research Professor in the Department of Economics at the University of California, Berkeley, since 2024, with joint appointments in the Goldman School of Public Policy.

At PSE, Zucman holds a chaired professorship and is the holder of the PSE Stone Center chair on wealth and income inequality. He directs the European Union Tax Observatory, an initiative focused on corporate tax avoidance and policy reforms, and co-directs the World Inequality Lab, which maintains the World Inequality Database tracking global income and wealth distributions.

Zucman maintains affiliations with research institutions including the Centre for Economic Policy Research (CEPR) as a research fellow and the National Bureau of Economic Research (NBER) as a faculty research associate. At Berkeley's Stone Center on Wealth and Income Inequality, he co-directs the summer research program.

Research contributions

Tax evasion and offshore wealth

Gabriel Zucman developed a macroeconomic approach to quantify offshore wealth by analyzing discrepancies between countries' reported assets and liabilities in international investment positions, revealing hidden flows to tax havens. In his 2013 analysis, he estimated that approximately 8% of global household financial wealth—equivalent to 10% of world GDP, or roughly $7.6 trillion as of 2013—was held offshore, primarily in jurisdictions like Switzerland, Luxembourg, and the Cayman Islands that facilitate non-reporting to tax authorities. These estimates derive from bilateral investment data showing "missing wealth" that balances global portfolios, with about half of such assets concentrated in Europe-based havens.

Zucman's research highlights the concentration of offshore evasion among the wealthiest individuals, using leaked bank data (e.g., HSBC Swiss leaks) and tax amnesty programs from Norway, Sweden, and Denmark. Collaborating with Annette Alstadsæter and Niels Johannesen, he found that 90% of offshore accounts in these countries belong to the top 1% of income earners, with the top 0.01% accounting for over 50% of hidden wealth and evading 20-30% of their true tax liabilities—far exceeding rates detected by standard audits, which capture only 5-10%. This skewed distribution implies annual global tax losses of $200 billion from personal income and wealth taxes, representing 10% of worldwide income tax revenue.

A U.S. study using IRS audit and enforcement data (Guyton, Langetieg, Reck, Risch and Zucman, NBER Working Paper 28542, 2021) estimated that accounting for offshore and pass-through evasion raises unreported income of the top 1% in 2006–2013 by 50% and raises the top 1% share of fiscal income by about 1 percentage point. Zucman's 2024 updates maintain that offshore financial wealth remains at 10% of global GDP, despite post-Panama Papers transparency efforts, as havens adapt via shell companies and trusts. His work attributes much of this persistence to the lack of coordinated sanctions, estimating that full enforcement could recover revenues equivalent to funding universal public goods like education in developing nations.

Zucman also examines behavioral responses, finding that higher audit risks prompt substitution from illegal offshore evasion to legal avoidance strategies, such as income shifting, without substantially reducing overall noncompliance among the ultra-wealthy. These insights, grounded in administrative and leaked datasets, challenge prior underestimations from self-reported surveys and emphasize the causal role of secrecy in enabling evasion, rather than mere portfolio optimization.

Wealth inequality measurement

Gabriel Zucman has advanced the measurement of wealth inequality through indirect estimation techniques that leverage administrative tax data, addressing the shortcomings of household surveys which often underrepresent top holdings due to sampling biases, non-response among the wealthy, and underreporting of assets. In collaboration with Emmanuel Saez, Zucman applied the long-established capitalization method to capital incomes reported on tax returns to infer underlying wealth stocks, combining this with aggregate national balance sheets from sources like the Federal Reserve's Flow of Funds to ensure consistency with macroeconomic totals. This approach, detailed in their 2016 study covering the United States from 1913 onward, applies a uniform rate of return—calibrated at around 6-7% for equities and lower for safer assets—to divide reported dividends, interest, and rents by the imputed yield, yielding estimates of wealth distribution by percentile.

The method benchmarks survey microdata against tax aggregates for the recent period while extrapolating historical distributions using estate tax returns and income capitalization for pre-1962 data when micro-files were limited. Saez and Zucman found that the top 1% wealth share in the US fell to about 22% by 1980 amid mid-century progressive taxation and wars but rebounded to 39% by 2014, contrasting with Survey of Consumer Finances (SCF) estimates that show slower growth at the top due to reliance on voluntary reporting. Adjustments for underreporting—estimated at 20-30% for high-income capital gains—and inclusion of pensions and closely held businesses further elevate top shares compared to raw survey figures. This framework underpins the Distributional National Accounts (DINA), co-developed by Zucman and colleagues, which allocates total national wealth from macroeconomic accounts to income groups using factor income distributions, enabling cross-country and time-series comparisons.

Globally, Zucman's 2019 review extends these techniques, reconciling national wealth surveys with offshore data and imputing top shares where direct observations are scarce, estimating that the top 0.1% hold 25% of world wealth as of 2016—higher than in most survey-based assessments which capture only 10-15% due to evasion and non-disclosure. The capitalization method assumes a uniform rate of return within each asset class. Using linked administrative data, Matthew Smith, Owen Zidar and Eric Zwick (Quarterly Journal of Economics, 2023) found that wealthy households earn much higher returns, with the interest rate on fixed income at the top "approximately 3.5 times higher than the average," so that uniform-return capitalization overstates top wealth. Their heterogeneous-return estimates put the 2016 top 1%, 0.1% and 0.01% wealth shares at 33.7%, 15.7% and 7.1%, increases of 6.6, 4.6 and 2.9 percentage points since 1989, below the Saez–Zucman series; the working-paper version described these trends as "less dramatic than some prior estimates." The authors nonetheless conclude that "wealth inequality is high and has risen substantially over recent decades." Empirical validation comes from matching DINA estimates to leaked datasets like Panama Papers, which confirm elevated offshore concentrations among the ultra-wealthy.

Corporate profit shifting and tax havens

Zucman has conducted empirical research quantifying the extent to which multinational corporations (MNCs) artificially shift profits to low-tax jurisdictions, often referred to as tax havens, thereby eroding the corporate tax base in high-tax countries. In collaboration with Thomas Tørsløv and Ludvig Wier, he developed a methodology that leverages discrepancies in aggregate country-level data on MNC sales, profits, and employee compensation to identify "missing profits" booked outside countries of economic activity. This approach exploits the fact that tax havens exhibit anomalously high profit-to-sales ratios—often exceeding 50%—while maintaining low wage-to-sales ratios, indicating limited real economic substance such as production or employment.

Their paper "The Missing Profits of Nations" estimates that approximately 36% of global MNC profits—equivalent to $616 billion in 2015—were shifted to tax havens, with the figure rising to $969 billion (37% of MNC profits) by 2019. U.S.-headquartered MNCs account for a disproportionate share, shifting about 54% of their foreign earnings to havens, compared to 30% for other nationalities, resulting in roughly 20% of total U.S. corporate profits being booked in such jurisdictions as of the mid-2010s—a tenfold increase from the 1980s. Key havens identified include the Netherlands, Luxembourg, Ireland, Hong Kong, and Bermuda, where affiliates report elevated profitability without commensurate real activity.

Zucman's subsequent work extends these estimates historically, revealing a steady rise in profit shifting from less than 5% of MNC profits in 1975 to over 37% by 2019, driven by the expansion of intra-firm transactions, transfer pricing manipulations, and the growth of the tax avoidance industry since the 1980s. These shifts correspond to annual global corporate tax revenue losses of $200–300 billion, concentrated in G7 economies, where MNCs originate most shifted profits but capture little of the tax savings due to haven residency rules. Zucman's analysis attributes this phenomenon causally to statutory tax rate differentials, with empirical tests showing that profit booking responds elastically to tax incentives rather than underlying productivity.

The research underscores mechanisms like debt shifting, intellectual property relocation, and royalty payments, which allow MNCs to allocate taxable income to low-tax entities while deducting expenses in high-tax ones. For instance, U.S. MNCs' post-2017 Tax Cuts and Jobs Act behavior showed limited repatriation of shifted profits, suggesting persistent incentives for avoidance despite reforms. Zucman's estimates, derived from Bureau van Dijk's Orbis database covering nearly all large MNCs, provide a benchmark for policy debates on base erosion and profit shifting (BEPS), though they rely on the assumption that abnormal haven profits reflect artificial rather than genuine intangible asset returns—a contention supported by low tangible investment correlations in havens.

Policy advocacy

Wealth tax proposals

Gabriel Zucman has proposed progressive wealth taxes to address the low effective tax rates paid by billionaires, which he estimates at approximately 0.3% of their wealth annually, compared to higher rates for average taxpayers. In the United States, collaborating with Emmanuel Saez, Zucman advocated for a wealth tax on the top 0.1% of families holding $9–13 trillion in assets, suggesting rates such as a 3% marginal tax above $1 billion, which they argued would curb wealth concentration without economic harm; critics note that most European countries that tried wealth taxes repealed them, citing capital flight and low revenue. Their analysis supports proposals like a 2% tax on net worth exceeding $50 million and an additional 1% above $1 billion, a design proposed by Senator Elizabeth Warren. Saez and Zucman estimated that it would raise $212 billion in 2019 and $2.75 trillion over 2019–2028, assuming the wealthy would shelter 15% of their wealth. Lawrence Summers and Natasha Sarin argued the estimates were greatly overstated because of avoidance and valuation problems. By Saez and Zucman's own description, the Summers–Sarin approach implied revenue of about $25 billion in 2019, roughly one-eighth of their figure. Saez and Zucman replied that the disagreement concerned the scale of avoidance, not the size of top wealth. They argued the proposal respected administrative feasibility through annual valuations of publicly traded assets and sampling for private holdings.

On the global scale, Zucman presented a blueprint for a coordinated minimum effective taxation standard targeting ultra-high-net-worth individuals, requiring those with over $1 billion in wealth to pay at least 2% annually. Zucman's 2024 report for the G20 Brazilian presidency estimated that this baseline proposal would affect roughly 3,000 billionaires worldwide and raise $200–$250 billion in annual revenue. Implementation would leverage domestic tools such as presumptive income taxes on unrealized gains or direct wealth levies, coordinated internationally via enhanced reporting on multinational ownership and "tax collector of last resort" mechanisms to prevent avoidance through residency shifts.

In France, Zucman's recent proposal, dubbed the "Zucman tax," calls for households with net assets exceeding €100 million to pay a minimum 2% tax on their total wealth, aiming to reverse the declining effective taxation of the richest amid concerns over inequality. He argues this floor would ensure billionaires contribute proportionally, halting the drop in their tax burden relative to middle-income groups, while international coordination mitigates flight risks. Zucman emphasizes that such taxes are administratively viable, drawing on historical European experiences and modern data from tax returns and financial accounts, without necessitating perfect valuation of all assets. Zucman estimated the tax would raise about €20 billion a year from roughly 1,800 households. In a September 2025 Le Monde op-ed, seven economists including Philippe Aghion, Christian Gollier and Xavier Jaravel estimated a deficit reduction of about €5 billion instead, arguing that empirical studies of past capital-tax reforms find that only about €0.25 of each euro of mechanical revenue survives tax avoidance and emigration in the long run; they relied in part on a July 2025 Conseil d'analyse économique report. Zucman replied that his design avoids the exemptions and caps that undermined earlier wealth taxes. LVMH chairman Bernard Arnault called the tax "a clearly stated desire to destroy the French economy," and Prime Minister Sébastien Lecornu said there was no "miracle tax." On October 31, 2025, the National Assembly rejected the Zucman tax by 228 votes to 172, and a Socialist 3% variant above €10 million by 228 to 171.

Global minimum tax and reforms

Gabriel Zucman has supported the international coordination of corporate taxation through the OECD's Pillar Two framework, established by an agreement among 137 countries in October 2021, which imposes a 15% global minimum effective tax rate on multinational enterprises with annual revenues exceeding €750 million. In a 2022 study co-authored with Dhammika Dharmapala, Kyle De Vox, and Li Liu, Zucman estimated that full implementation of this reform would generate approximately $220 billion in additional annual global tax revenue by reducing profit shifting to low-tax jurisdictions, though actual yields depend on domestic top-up taxes and compliance. He views this as a step toward curbing tax competition but has noted potential loopholes, such as substance carve-outs, that could undermine its effectiveness if not addressed.

Building on the corporate minimum tax model, Zucman proposed extending similar multilateral standards to individual wealth taxation. In a June 25, 2024, report prepared for G20 finance ministers and led by the EU Tax Observatory, he advocated for a coordinated 2% minimum effective tax on the net wealth of ultra-high-net-worth individuals exceeding $1 billion, applicable to roughly 3,000 billionaires worldwide. This framework would allow countries to impose top-up taxes to reach the minimum after crediting foreign levies, aiming to raise $200–$250 billion annually while preventing relocation-driven tax avoidance, with implementation feasible via existing information exchange networks like the Common Reporting Standard.

Zucman's reforms emphasize empirical data on low effective tax rates—often below 1% of wealth for billionaires—and advocate for enhanced transparency, such as public registers of beneficial ownership and real-time cross-border data sharing, to enforce these minima without relying on unilateral measures that provoke capital flight. He argues that such global standards, akin to those for corporations, are essential for fiscal sovereignty amid rising wealth concentration, though critics question administrative feasibility and potential disincentives to investment.

Reception and criticisms

Awards and academic recognition

In 2023, Zucman was awarded the John Bates Clark Medal by the American Economic Association, a prestigious honor given annually to an economist under the age of 40 for significant contributions to economic thought and knowledge. The Association cited his research on wealth inequality, offshore wealth, and international tax evasion.

In 2024 he was elected a Fellow of the Econometric Society.

Zucman received the Bernacer Prize in 2019 from the Bernacer Prize Committee, awarded to young European economists for exceptional work in macroeconomics and finance. That same year, he was granted a Sloan Research Fellowship by the Alfred P. Sloan Foundation, supporting early-career researchers demonstrating high promise in their fields.

Earlier recognitions include the 2018 Prize for the Best Young French Economist, conferred by Le Monde and the Cercle des économistes for innovative economic analysis. In 2017, he earned the Excellence Award in Global Economic Affairs from the Kiel Institute for the World Economy, honoring his research on global wealth and taxation. In 2021, Zucman was selected as an Andrew Carnegie Fellow by the Carnegie Corporation of New York to advance scholarship on inequality and related policy issues. His book The Triumph of Injustice (co-authored with Emmanuel Saez) received the Hans Matthöfer Prize from the Friedrich-Ebert-Stiftung and the Colbert Prize from the Fondation Colbert. Additionally, in 2014, his PhD dissertation was honored with the French Economic Association award for the best in the field.

In 2019, Harvard's Kennedy School faculty voted to offer Zucman a tenured position, but Harvard's president and provost declined to approve it. The New York Times reported that this was "partly over fears that Mr. Zucman's research could not support the arguments he was making in the political arena," according to people involved in the process. He was subsequently granted tenure at Berkeley.

Empirical and methodological critiques

Critiques of Zucman's empirical approaches to measuring wealth and income inequality have centered on assumptions about unreported income and its distribution. In collaboration with Thomas Piketty and Emmanuel Saez, Zucman estimated that the top 1% income share in the United States rose from 9% in 1960 to 15% in 2019, attributing much of the increase to underreported high-end earnings concentrated among executives and the wealthy via offshore accounts. Gerald Auten (U.S. Treasury) and David Splinter (Joint Committee on Taxation), in the Journal of Political Economy (2024), argue that top-share estimates based only on individual tax returns "are biased by tax-base changes, social changes, and missing income sources." Correcting for these, they find that pretax "top income shares are lower and have increased less since 1980," and that "increasing government transfers and tax progressivity have resulted in rising real incomes for all income groups and little change in aftertax top income shares." Piketty, Saez and Zucman reply that the gap stems from Auten and Splinter's allocation of untaxed income, including assigning growing untaxed partnership income to less-wealthy sole proprietors, and from their assumptions about untaxed business and capital income.

Auten and Splinter also attribute part of the measured rise in top shares to changes in reporting rather than in underlying income: after the Tax Reform Act of 1986, much business income shifted from corporate to individual tax returns, and declining marriage rates increased the number of low-income tax units. They note that income reported on tax returns accounts for only about 60% of national income, so assumptions about the missing remainder strongly affect the results. These disputes highlight sensitivities in Zucman's imputation methods, where small changes in assumptions about evasion rates—drawing from Scandinavian audit studies extrapolated globally—can significantly alter inequality trends.

Zucman's offshore wealth estimates, introduced in his 2013 paper using balance-of-payments discrepancies to infer hidden financial assets (estimating 8% of global household financial wealth offshore, equivalent to 10% of world GDP), have faced scrutiny for methodological limitations. The approach captures only financial assets, excluding non-financial holdings like real estate, potentially understating total offshore wealth or misrepresenting its composition, as noted in subsequent analyses reconciling global aggregates. Critics argue that discrepancies may stem from measurement errors, capital flight misclassifications, or unreported inward investments rather than pure evasion, leading to overstated net foreign asset positions for creditor nations like the US and Europe.

In the 2019 book The Triumph of Injustice (with Emmanuel Saez) and in accompanying charts published in The New York Times and The Washington Post, Zucman and Saez presented effective tax rates for the top 400 or top 0.001 percent that fell to roughly 23 percent by the late 2010s—below the rate they assigned to the bottom half of the distribution. These figures diverged sharply from the authors’ own earlier published series. In the 2018 Quarterly Journal of Economics paper with Thomas Piketty and Saez, the same top 0.001 percent group showed an overall effective rate of approximately 40–44 percent in recent years, with only a modest decline from the early 1960s. The 2019 series was produced by two principal methodological changes: (1) allocating 100 percent of corporate-tax incidence to shareholders rather than the conventional mixture of capital owners and labor used in the 2018 paper and in most official distributional analyses (CBO, JCT, Tax Policy Center); and (2) excluding refundable tax credits such as the Earned Income Tax Credit from the tax liabilities of lower-income groups, treating them as pure transfers. The first change causes top rates to track the decline in corporate statutory rates; the second raises the apparent rate paid by the bottom quintile relative to standard effective-tax-rate conventions. Economic historian Phillip Magness documented that, around the time the new figures were released, the online data-replication file for the published 2018 QJE paper was replaced on Zucman’s website with a version that matched the 2019 numbers (the original file was later restored after public criticism). Subsequent working papers by Saez and Zucman have offered a theoretical distinction between “current distributional analysis” (assigning taxes according to the legally taxed factor without full incidence shifting) and conventional incidence analysis; critics note that this framework has not displaced standard practice in official distributional tables and that the resulting charts remain sensitive to the same two assumptions. Larry Summers and Wojciech Kopczuk have separately described aspects of the underlying data as substantially inaccurate and misleading. Zucman has defended these by emphasizing hidden capital income, but sensitivity to imputation rules persists, as reallocating unreported income proportionally to reported earnings skews burdens upward for high earners beyond audit-verified patterns. David Splinter, using national-accounts income, estimates that U.S. effective tax rates rise from 2% for the bottom quintile to 45% for the top hundredth of one percent. In an August 2025 comment on later "top 400" estimates by Balkir, Saez, Yagan and Zucman, he adjusted for Forbes family wealth spread across multiple tax returns, double-counted capital income, missing taxes and standard income definitions, and found that the top 400's effective rate exceeded the overall rate by about 13 percentage points instead of falling below it. He found the top-400 rate somewhat lower than that of the top hundredth of one percent, which he attributed to the tax system targeting income rather than wealth.

Economic impact debates

Debates surrounding the economic impacts of Gabriel Zucman's policy proposals, particularly progressive wealth taxes and international corporate tax reforms, focus on their effects on public revenue, capital allocation, investment incentives, and long-term growth. Zucman and co-authors assert that a coordinated 2% annual minimum tax on billionaire wealth exceeding $1 billion could generate $200-250 billion in global revenue yearly from approximately 3,000 individuals, primarily by curbing existing evasion and avoidance without substantially reducing productive investment, as much billionaire wealth is already held in low-return, tax-minimizing assets like art or private equity. They argue this revenue could fund infrastructure and social programs, potentially enhancing growth through reduced inequality, drawing on historical evidence from periods of higher top marginal rates where capital flight was limited under strong enforcement.

Critics, including economists from institutions like the Peterson Institute for International Economics, counter that wealth taxes historically yield minimal net revenue due to high administrative costs, valuation disputes, and behavioral responses such as asset relocation or reduced risk-taking, as evidenced by the repeal of such taxes in countries like Sweden (2007) and France (2017), where emigrants and capital outflows exceeded projections. Analyses suggest that even modest wealth levies distort savings and entrepreneurship by taxing unrealized gains, potentially lowering the capital stock and GDP growth by 0.2-1% over time, with empirical studies showing elasticities of taxable income to wealth taxes around 0.2-0.8, implying significant deadweight losses. In France, proposals akin to Zucman's, targeting assets over €100 million, have been projected to prompt tax flight among high-net-worth individuals, exacerbating fiscal deficits rather than resolving them, as seen in post-IFI emigration trends. In California, the Saez–Zucman tax-rate estimates figured in the campaign for Proposition 40, a 2026 one-time billionaire tax. Economic historian Phillip W. Magness argued that the campaign's claim that billionaires pay lower rates than workers depends on Saez and Zucman assigning the entire corporate tax to shareholders; by that change, he wrote, a 41% rate for the top 0.001% in their 2018 Quarterly Journal of Economics data became 23%. A Hoover Institution analysis estimated that the tax would collect about $40 billion rather than the proponents' $100 billion, and that the state would lose at least $25 billion over the long run once income-tax revenue lost to departing billionaires is counted. It noted that nine of the twelve European countries that had wealth taxes in 1990 had repealed them by 2025, citing administrative costs, avoidance and outmigration, and that at least six billionaires, including Sergey Brin and Larry Page, publicly left California before the tax's January 1, 2026 residency date, taking roughly $536 billion, about 30% of the base, with them.

Regarding the global minimum corporate tax of 15% under Pillar Two, which Zucman has supported and analyzed, simulations indicate annual revenue gains of $60-100 billion for low-tax jurisdictions by repatriating shifted profits, reducing distortions from profit-shifting estimated at 10-20% of global corporate profits. However, opponents highlight risks of increased compliance burdens, potential pass-through of costs to consumers via higher prices, and diminished foreign direct investment in high-tax countries, with general equilibrium models showing welfare losses from reduced multinational efficiency, particularly in developing economies reliant on tax competition. Zucman maintains that these reforms enhance sovereignty by limiting tax competition's race-to-the-bottom dynamics, but empirical evidence from early implementations remains limited as of 2025, with debates ongoing over whether revenue boosts offset incentives for further base erosion via non-taxed channels like intragroup financing.

Personal life

Citizenship and residences

Gabriel Zucman holds dual citizenship in France and the United States. He was born in Paris, France, on June 26, 1986.

Zucman maintains academic appointments that reflect transatlantic professional residences: he serves as a Chaired Professor of Economics at the Paris School of Economics in Paris, France, and as an Associate Professor of Economics at the University of California, Berkeley, in Berkeley, California. His dual roles indicate he divides time between these locations, though primary residence details remain private.

Family background

Gabriel Zucman was born in Paris in 1986 to two physicians. His mother works as a researcher in immunology, while his father specializes in treating HIV patients.

Zucman grew up in comfortable, well-off circumstances in Paris, attending prestigious schools during his early education. Little public information exists regarding extended family origins or ancestry, with Zucman himself sharing minimal details about his private life beyond these parental professions.