Gabriel Zucman (가브리엘 주크만), an economist at the University of California, Berkeley, has proposed imposing a minimum annual tax of about 2 percent on ultra-wealthy people with net assets exceeding 100 million euros, reigniting debate over taxing billionaires.

Cleantechnica, an electric vehicle publication, reported on April 6 that his new book, despite being a short volume of about 60 pages, triggered a vote in the French parliament and was placed on the Group of 20 (G20) discussion table as a concrete policy proposal.

Zucman pointed to the starting point of the problem as the regressivity of tax systems. He argued that in major countries such as the United States, France, Germany and the Netherlands, ultra-wealthy people face lower effective tax rates than middle-class workers. He described this not as a simple institutional loophole but as a structural outcome designed through methods such as placing assets into corporate structures or delaying taxable events. He also noted that unless taxation is triggered through dividends or sales, an income tax system centered on wages makes it difficult to properly tax accumulated wealth.

His proposed "2 percent minimum tax" is a different concept from an existing wealth tax. It would require people with net assets exceeding 100 million euros to bear a minimum annual tax burden of about 2 percent, but would impose no additional tax if they have already paid at least that level through other taxes. Zucman described it as "not a ceiling but a floor". The proposal is being discussed in France under the name "Taxe Zucman".

He also presented estimates of the revenue effect. Applying the system to about 3,000 dollar-denominated billionaires worldwide could secure about $250 billion a year in tax revenue, and expanding the scope to centi-millionaires with net assets of at least $100 million could raise an additional $140 billion a year, he calculated. In France, he argued the tax would apply to about 1,800 people and could also help ease fiscal deficits, citing that the wealth of the top 500 increased from 6 percent to 42 percent of gross domestic product (GDP) over the past 30 years.

On the possibility of wealthy people leaving, a counterargument often raised, he suggested international coordination as a solution. Zucman cited the global minimum corporate tax of 15 percent being implemented in more than 130 jurisdictions, and stressed that if major countries cooperate, the space for meaningful avoidance is limited. He also mentioned the need to introduce an exit tax to prevent tax avoidance through changing residency. He cited a Stanford study as a basis for arguing that billionaires are less likely to actually migrate than the general population.

Zucman framed the debate as a political issue rather than a technological one. He said excessive concentration of wealth leads to deeper concentration of power through corporate acquisitions, the shaping of regulation, political funding and influence over the public sphere. He stressed that "wealth is power" and said the current structure, in which effective tax rates remain at 0 to 1 percent while assets rise 7 to 10 percent a year, is the result of policy choices. He added that progressive taxation is not only a way to secure resources but a core mechanism for democracy to prevent permanent oligarchization.