But it’s not just an abstract concern—it’s already happening.

Martin Ott, the CEO of Taxfix, the Berlin-based tax app valued at more than $1 billion, exclusively told Fortune some of its wealthy U.K.-based clients have been eyeing an exit—but he doesn’t recommend it. 

“Yes, there are certain customers, at a certain income bracket, that are moving to save money abroad,” Ott, a former Meta exec, said. “I always encourage people to stay where you are.”

‘You have a social responsibility to invest in your country’ 

In 2025, more millionaires have left the U.K. than in any other nation. According to the Henley Private Wealth Migration Report 2025, about 16,500 millionaires uprooted last year, totaling about $91.8 billion. This translates to a 9% reduction in the U.K.’s millionaire population over the last decade, in part thanks to fallout from Brexit, political uncertainty, and tax changes. 

But Ott argues that leaving now is shortsighted. If the country’s top founders and high earners leave, it will weaken the very ecosystem they once thrived in. 

“Saving taxes is one thing, but at the same time, you also have a social responsibility to make sure you invest in a country,” he explained.

In his eyes, wealth creates an obligation to keep the ecosystem healthy for the next wave of builders, operators, and job seekers. Ott says that’s why many of his friends and peers—people who could easily decamp to Dubai or Montenegro—are deliberately staying put. 

“They’re saying, we’re not moving…We really want to make sure we also give back and build cool stuff that makes it worthwhile staying.”

To him, the more responsible choice is to weather the cycle, build through it, and strengthen the system from inside: “You don’t want a brain drain…I can only just encourage everyone to stay, build great new businesses, create an environment where entrepreneurs want to start something.”

Plus, pressure creates diamonds

Looking back on his early fintech days in London during the financial crisis, Ott recalled holding hundreds of millions of customers’ money in bank accounts, not knowing if the banks would survive the next day—and he said it taught him a lesson that still matters now.

“There was also that feeling that the world is going down. Do we need to move somewhere else? No, everything goes in phases,” Ott said. He credits the dark period with teaching him “what it means to go through crisis,” including how to manage his own personal health and how to be a better manager to others when the chips are down. But more importantly, it highlighted that downturns aren’t forever.

“Taking a more balanced, long-term view—that’s what I learned,” he added. “Things aren’t as bad as they look in the moment.

“And then new opportunities are born, and you can deal with crisis, because it’s constant, you’ll always have stuff that’s getting thrown your way.”

A version of this story originally published on Fortune.com on November 25, 2025.

Read more on wealth from Fortune’s Orianna Rosa Royle:

• How Montenegro became the world’s fastest-growing hub for millionaires
• This millennial became a millionaire before turning 30 thanks to early investments in Deliveroo and Revolut—he shares how Gen Z can spot the next startup jackpot
• This millennial went from being a builder on $5 an hour to launching (and selling) Wingstop UK for $532 million—with zero restaurant experience
• A 2-year taste of the office was enough to make 3 grads quit. Now they run a $13.2 billion investment firm: ‘We didn’t want a traditional job again’
• A Gen Xer sold his company for $1.6 billion. He kept less than $100 million and gave the rest away because he doesn’t ‘believe in billionaires’