.'' Zucman is known for his research on tax evasion and international tax avoidance, but has made contributions to the field of public economics more broadly. In August 2014 in
Capital is Back, Zucman and French economist
Thomas Piketty investigate the evolution of aggregate wealth–to–income ratios in the top eight developed economies, reaching back as far as 1700 in the case of the U.S., U.K., Germany, and France, and find that wealth–income ratios have risen from about 200–300% in 1970 to 400–600% in 2010, levels unknown since the 18th and 19th centuries. Most of the change can be explained by the long-run recovery of asset prices, the slowdown of productivity, and population growth. Zucman has co-written several papers with
Thomas Piketty. In 2017–18, Zucman focused on the scale of multinational tax avoidance by
base erosion and profit shifting ("BEPS") tools in the largest
corporate tax havens. Research published by Zucman, Tørsløv and Wier in June 2018, showed that Ireland is the largest corporate tax haven in the world, even larger than the entire Caribbean corporate tax haven system. This research also showed that tax disputes between high–tax jurisdictions and corporate tax havens are extremely rare, and that tax disputes really only occur between high–tax jurisdictions.
The Hidden Wealth of Nations (2015) The Hidden Wealth of Nations (2015), Zucman's most influential work, primarily focused on the fact that official national statistics underestimate foreign assets because offshore wealth is not properly accounted for. In his book, he used systematic anomalies in international investment positions to showcase hidden offshore wealth. These anomalies indicated that global assets exceeded global liabilities, which is theoretically impossible, thereby signaling the potential presence of missing offshore wealth. Before Zucman's work, most estimates of global wealth inequality relied on national tax records and surveys, which systematically excluded offshore assets. His methods allowed him to detect wealth that is intentionally hidden. This work changed how governments and economists understood tax evasion. It later went on to influence international G20 policy discussions and research for the World Inequality Database. His key findings were that 8% of global financial wealth is held offshore, roughly $7.6 trillion. This finding laid the groundwork for his advocacy of the global wealth tax through the EU Tax Observatory and the G20 Summit. His estimates are now used in debates about global tax transparency and have contributed to shifting tax evasion into mainstream economic and political debate. While his estimates have been widely influential, some economists have noted the difficulty of precisely measuring highly mobile and hard to find financial assets, and therefore state that offshore wealth may fluctuate with regulatory and financial changes. Along with
James R. Hines Jr. and
Dhammika Dharmapala, Gabriel Zucman is noted as a leader in the study of tax havens, and his papers are amongst the most cited research on tax havens. Much of Zucman's other research deals with the effect of the
G20's crackdown on tax havens and corporate tax havens, cross–border taxation and multinational profit shifting, the long–term relationship between wealth and inheritance, and the trajectory of wealth inequality in the United States. Zucman's research and commentary have been cited by international news outlets such as The New York Times and The Guardian. (†) Identified as one of the 5
Conduits (Ireland, Singapore, Switzerland, the Netherlands, and the United Kingdom), by CORPNET in 2017. (‡) Identified as one of the largest 5
Sinks (British Virgin Islands, Luxemburg, Hong Kong, Jersey, Bermuda), by CORPNET in 2017.
Wealth tax on billionaires Zucman researches and advocates wealth taxation as a fiscal tool to address extreme inequality and combat tax evasion in an era of rapidly growing billionaire fortunes. Specifically, he has supported a 2% wealth tax on those with wealth above €100 million. The basis of Zucman's argument is that contemporary tax systems are highly regressive at the top with the ultra-wealthy often paying effective tax rates lower than average. According to one analysis cited by Zucman, billionaires paid on the order of only ~0.3% of their wealth per year in total tax. To enforce his wealth tax on billionaires, Zucman proposes multilateral coordination including expanding automatic exchange of financial information across jurisdictions and even developing a global asset registry to ensure the wealthy cannot relocate or hide funds to escape his tax. ==Personal life==