Most developed countries are set to gain more millionaires in the next 5 years — with 2 big outliers

• The UK and the Netherlands will see a decline in millionaires by 2028, per a new UBS report.
• Both countries saw an influx of millionaires from people choosing to move there.

Most developed countries are set to gain more wealthy people in the next five years — with two big outliers.

UBS tracked 56 countries for its annual wealth report, released last week. The financial services firm found that 52 of them will add millionaires by 2028. Some countries, like Taiwan, will gain as many as 50% more millionaires during that time.

But the United Kingdom and the Netherlands make "notable exceptions" on this list, per UBS, because both are forecasted to lose millionaires.

The UK and the Netherlands had attracted "nomadic wealth" — people who chose to move to those countries, rather than those who made their money locally — wrote Paul Donovan, chief economist at UBS Global Wealth Management, in an email to Business Insider.

"Wealth has become more mobile in several parts of the world, as a function of numerous push and pull factors," Donovan said. "If more millionaires are changing location, then those economies which are disproportionately attractive for nomadic wealth are also more vulnerable to movements in that nomadic wealth."

The UK's three million millionaires put it third among countries with the highest number of millionaires last year, as measured in US dollars, per UBS.

That's "more millionaires than there should be, given the size of the economy," Donovan said at a media event on July 10.

However, UBS forecasts this number to decline by 17% by 2028. The loss continues a trend: The UK lost 16,500 millionaires between 2017 and 2023, per immigration consultancy Henley & Partners. Some millionaires have been leaving the UK in search of better taxes and more stable, business-friendly politics, while others were hit by sanctions against Russia.

The UK is changing a longtime millionaire-friendly tax policy that effectively allowed foreign wealth to be earned tax free. The tens of thousands of UK residents who qualify as "non-dom" filers are now set to eventually pay taxes on their foreign earnings, a major disruption for the wealthy elite. Alternative ports of call for this group of millionaires will likely include Paris, Dubai, Sydney, and the Italian Riviera, per Henley & Partners.

The Netherlands also similarly holds an outsize number of wealthy residents: over 1.2 million millionaires, which is about the same as Italy and Spain but with a smaller economy than its peers. UBS forecasts the country's millionaire count will go down 4% by 2028.

From 2013 to 2023, the Netherlands' millionaire number jumped 32%, according to data provided to BI by Andrew Amoils, head of research at New World Wealth.

The "growth rate there has been good, especially compared to [the] UK," Amoils told BI.

Geopolitical instability in Europe, marked by the rise of far-right parties and potential conflicts, has made wealthy individuals seek alternative residence options through investment migration programs. In recent months, applications have spiked nearly 60% for such programs, a spokesperson for Henley and Partners told Business Insider. These programs offer residence rights or citizenship in exchange for significant financial contributions.