As donor governments grapple with mounting debt and shift budgets toward defence, humanitarian and development funding for low- and middle-income countries is shrinking at an unprecedented rate. A new study published in The Lancet argues that taxing the super-rich could fill the gap and avert tens of millions of deaths among the world's most vulnerable populations.
The research, led by Davide Rasella of ISGlobal in Barcelona and Lucio Exposito of the ICESI School of Economics and the University of East Anglia, models the impact of several wealth-redistribution policies. It finds that a 3% annual tax on billionaires' wealth would be the most effective, potentially preventing 29.5 million deaths by 2030. A 1% wealth tax would still avert 15.1 million deaths.
Other measures also show significant potential. A tax on financial transactions, often called a Tobin tax, could prevent around 24.5 million deaths, while a global minimum tax on multinationals with revenues above €750 million could avert roughly 20.1 million. The authors stress these are modelled estimates, not predictions, but they highlight the scale of what is at stake.
Aid cuts with deadly consequences
Official development assistance (ODA) — government aid targeting health, sanitation, education, and infrastructure in poorer countries — fell by nearly a quarter across all major donors in 2024 and 2025. Further reductions are expected in the coming years. The study warns that if current defunding continues, it could lead to 7.6 million deaths by 2030, including 1.4 million among children under five.
“With donor countries facing growing indebtedness and increasingly reallocating resources towards military spending, funding humanitarian assistance via the taxation of large fortunes was one of the most viable strategies,” said Exposito, a senior economist at the study.
The research analysed data from 59 low- and lower-middle-income countries between 2002 and 2021, representing 3.9 billion people. It then modelled how different tax policies could offset projected aid reductions through 2030.
Wealth taxes gain momentum
Wealth taxation is not a new idea, but it is gaining renewed political traction. Spain introduced a solidarity wealth tax in 2022, applying rates between 1.7% and 3.5% on net assets above €3 million. France has debated a 2% tax on ultra-high-net-worth individuals, though a recent proposal was rejected by the Senate. Sweden had a wealth tax for decades before abolishing it in 2007.
The idea also has support from some of the world's richest people. At the World Economic Forum in Davos earlier this year, hundreds of millionaires and billionaires from dozens of countries called on governments to increase taxes on the super-rich.
“We live in an extremely unequal world, where a small number of individuals and corporations are accumulating wealth at an unprecedented pace and scale, while millions of vulnerable people continue to die for lack of access to basic, often low-cost, humanitarian interventions,” said Rasella, who conceived and coordinated the study.
The findings come as Europe's own economic challenges — such as France's sluggish growth and Portugal's uneven performance — complicate the fiscal picture for donor nations. Yet the study suggests that even modest taxes on extreme wealth could have a transformative effect globally.
“Our findings show that implementing even modest wealth redistribution policies, such as those proposed in recent international agreements, could literally save tens of millions of lives in the coming years,” Rasella added.
With over 3,000 billionaires worldwide holding a record €17.4 trillion, the study argues that the resources exist to prevent a humanitarian catastrophe. The question, it implies, is political will.
