Berkeley economist Gabriel Zucman is one of the pre-eminent global experts on taxation, and the lengths that big business and the ultra-rich go to in minimising their tax liabilities. Clocking in at 65 pages, his latest book is a short, sharp treatise on why We Need to Tax Billionaires.
*** A version of this book review was first published in The Irish Times on 25 July 2026 ***
He begins by setting out the mechanisms through which the ultra-rich achieve effective tax rates lower than those faced by the working and middle classes. The wealthy generate average returns of 6% per annum, according to Zucman, reflected in increasing asset values. However, the income generated for the purposes of income tax is negligible while wealth taxes, where they do exist, are ineffective. The author notes, for example, that billionaires in France face an effective tax rate half that of the average French person.
Zucman’s proposal is for a minimum annual 2% tax levied on the wealth of those with more than $100m in assets. He estimates that, if implemented globally, this could raise between $300 billion and $380 billion per year, of which €67 billion in Europe.
To be effective, such a wealth tax would need to address three shortcomings of existing wealth taxes: loopholes should be closed; incentives to offshore wealth should be curtailed; and international bank transparency data should be used to
tackle evasion.
With “no economic, moral or legal foundation not to tax wealth that produces no income”, the author argues that a global minimum wealth tax would complete the “unfinished revolution” that began with the introduction of progressive individual income taxes more than a century ago. He goes on to claim that “like income tax, it, too, will eventually gain broad acceptance as the logical and necessary measure it is.”
As a means to achieve global agreement, Zucman points to the OECD-led initiative that resulted in the global minimum corporate tax rate of 15%. It also had its detractors, and those who said it could never be done.
There are strong arguments for Ireland to introduce a meaningful tax on wealth to broaden our tax base. This shouldn’t wait until there is a global agreement in place, but we should advocate in parallel for such an agreement at EU level and through our OECD membership.
vicduggan 