A new EU-commissioned study has reviewed evidence on wealth-related taxes across Europe and other countries, finding that the revenue raised and the fairness effects depend heavily on how the taxes are designed and how taxpayers respond.
The study was ordered by the European Commission in 2024 amid global discussions in international forums including the OECD, the G20 and the United Nations, the Commission disclosed in a statement on Wednesday.
It is published in two volumes, with the first surveying academic research across five categories of taxes and mapping wealth-related tax regimes in EU Member States.
The review found some evidence that net wealth taxes and inheritance and gift taxes can affect people’s movement within a country, but reported limited evidence on whether such taxes influence the international mobility of ultra-high-net-worth individuals.
The second volume uses case studies from countries that currently have — or previously had — a wealth tax, including detailed analysis of Austria, France, Germany and Spain, as well as Norway, Switzerland and Colombia.
Case studies: revenue and “tax gaps”
The analysis found wealth taxes examined in the case studies have not been a major source of revenue, and pointed to “tax gaps” as one explanation — differences between tax theoretically due and what is collected, for reasons including tax reliefs, exemptions or inadequate compliance, the Commission said.
It also added the study found outcomes for both revenue and equity — including “horizontal” equity (similar taxpayers treated similarly) and “vertical” equity (different taxpayers treated differently, often by ability to pay) — were strongly influenced by tax design and taxpayers’ responses.
The report suggested that publishing tax gaps regularly could encourage voluntary compliance.
The study also cited the role of exchanging information on beneficial owners, and improving real estate and asset registration, as well as institutional factors such as third-party reporting and digitalising tax administrations.
