How Many Millionaires Are in the UK? Why the 442,000 Estimate Is Not the Whole Story

Britain has lost millionaires on a real-terms sterling measure. The Adam Smith Institute’s Millionaire Tracker estimates that 442,000 adults living in Britain had inflation-adjusted net wealth of at least £1 million in 2025. That is 7% fewer than its 2024 estimate and the lowest point in its modelled series since 2008.

This is not simply a dollar exchange-rate effect. The ASI measure is designed to hold the sterling threshold constant after inflation, so its result means fewer people cleared the same real £1 million bar.

The harder question is why. The institute points to weaker real asset values, low household saving and the emigration of high-net-worth individuals. Its model supports a decline in the estimated total, but it does not directly count departures or divide the fall among those causes.

A different dataset gives a different headline. The UBS Global Wealth Report 2026 estimates that the UK added 43,139 US-dollar millionaires during 2025, taking its total to approximately 2.43 million.

The UBS rise does not cancel out the ASI decline. The two studies measure different wealth thresholds in different currencies, treat inflation differently and use separate models.

The UK millionaire count: two very different answers

Measure	Adam Smith Institute	UBS
Estimated UK millionaires in 2025	442,000	2.428 million
Annual change	Down 7%	Up 1.8%
Change in people	Not presented as a directly observed flow	Up 43,139
Threshold	At least £1 million in inflation-adjusted individual net wealth	At least US$1 million in nominal individual net wealth
Included wealth	Property, pensions, financial and other real assets, less liabilities	Financial and non-financial assets, including private pensions, less debt
Type of result	Modelled estimate	Modelled estimate

Is the fall in UK millionaires just a currency issue?

No. The ASI headline uses a constant-price sterling threshold, so it is not created by converting British wealth into dollars. It estimates that fewer people had enough net wealth to clear an inflation-adjusted £1 million threshold.

Currency does help explain why UBS can show growth at the same time. US$1 million is worth materially less than £1 million, so UBS starts with a lower bar. Its calculation is also sensitive to exchange rates: a stronger pound can turn someone into a dollar millionaire even if the sterling value of their assets barely changes.

Inflation matters differently in the ASI series. Someone can remain a nominal millionaire yet fall below £1 million once their wealth is restated in constant prices. That is still a loss of real purchasing power, even if the person has not moved country and their nominal balance has not fallen.

What does the 442,000 figure actually measure?

The Adam Smith Institute does not have a list of every millionaire in Britain. No such up-to-date register exists.

Its tracker starts with aggregate UK household net worth from the ONS National Accounts. It then uses a Pareto distribution, a statistical model commonly used for the upper end of wealth distributions, to estimate how many adults sit above £1 million.

The model is calibrated against nine waves of the ONS Wealth and Assets Survey. The institute says its method is better suited to tracking changes from year to year than to establishing a precise absolute headcount.

That caveat is important. The tracker blends aggregate National Accounts data with a distribution estimated from a separate household survey. The 442,000 figure should not be presented as an official census.

There is another reason to be cautious about false precision: the tracker page currently describes its constant-price calculation using two different base years. Its main definition refers to 2025 prices, while a methodology sentence refers to 2015 prices. Until that is clarified, “inflation-adjusted” is the safest description.

Does the tracker show that 7% of Britain’s millionaires left?

No. It shows a 7% fall in the estimated number of real-terms sterling millionaires, not a 7% emigration rate.

Someone can fall below an inflation-adjusted £1 million threshold without moving anywhere. Changes in real asset values, inflation, liabilities or other model inputs can move the estimated count.

The institute attributes the longer-term decline to several factors. It says higher interest rates and weaker confidence have reduced the inflation-adjusted values of pension pots and high-end London property, while Britain’s low savings rate has slowed the creation of new millionaires. It also points to high-net-worth people leaving Britain or deciding not to move here.

The valuation and savings explanations describe ways the modelled count could move without anyone leaving the country. The migration claim needs more caution: departures and foregone arrivals are not separately observed in the published methodology. Claims that the abolition of non-dom status, high taxation or a culture hostile to wealth creation caused that behaviour are policy interpretations, not causal findings produced by the tracker.

The tax backdrop has undoubtedly changed. From 6 April 2025, the remittance basis was abolished. UK residents are generally taxed on worldwide income and gains, while qualifying new residents can claim relief under the foreign income and gains regime during their first four UK-resident tax years after at least ten consecutive years of non-UK residence. From the same date, overseas assets can fall within Inheritance Tax when someone meets the long-term UK residence test, generally after ten consecutive UK-resident years or ten of the previous twenty.

Those reforms could affect future migration and investment decisions. They do not, by themselves, prove that the 2025 fall in the ASI estimate was caused by a millionaire exodus.

What do official UK wealth statistics show?

The most recent detailed ONS household wealth survey covers April 2020 to March 2022, so it cannot give us a definitive 2025 millionaire count.

It found:

• Median household wealth in Great Britain was £293,700.
• The wealthiest 10% of households had at least £1,200,500.
• The wealthiest 1% had at least £3,121,500.
• Property accounted for 40% of household wealth and private pensions another 35%.

These are household figures rather than individual figures, and they cover Great Britain rather than the whole UK. They are useful context, not a direct comparison with either the ASI or UBS estimates.

The ONS has also suspended accredited-statistics status for the latest Wealth and Assets Survey round while it works on response rates and data quality. Its household wealth quality guide notes differential non-response among very-high-wealth households, which makes the top of the distribution particularly difficult to measure.

Meanwhile, the ONS national balance sheet for 2026 estimates that nominal UK household net worth rose by £146.1 billion to around £10.8 trillion in 2025. That can coexist with a fall in the number of inflation-adjusted sterling millionaires, but it does not look like a simple story of national wealth evaporating.

Why this matters for UK investors

The most useful lesson here is not political. It is about how we measure wealth.

A millionaire is not necessarily holding £1 million in cash

For many British households, most wealth sits in a home and a pension. Both can be valuable while remaining difficult to spend today. Net worth, liquid wealth and income are three different things.

That is why headlines about millionaire numbers can feel disconnected from everyday financial security. A homeowner with a valuable property and a defined-benefit pension may qualify on paper while having relatively modest disposable income.

Asset prices can move people across an arbitrary line

Property, bonds, equities and pension valuations all respond to inflation and interest rates. A change in valuation can move people above or below £1 million without changing the underlying productive capacity of the economy.

My guide to why asset prices change explains why rates, liquidity and expectations can have such a large effect on paper wealth.

Real purchasing power matters more than a nominal milestone

Reaching £1 million sounds definitive, but its spending power changes over time. Investors should measure progress after inflation rather than treating a round number as the finish line.

You can use my compound interest calculator to model how regular contributions, returns and inflation affect a long-term target.

One macro headline should not change a sound portfolio

Whether the “correct” millionaire estimate is 442,000 or 2.43 million should not dictate your asset allocation. A long-term plan still rests on diversification, sensible costs, tax-efficient wrappers and behaviour during volatile markets.

For most investors, choosing an appropriate balance between active and passive investing will matter more than trying to trade around a modelled wealth statistic.

So, has Britain lost millionaires?

Yes, according to the ASI’s constant-price sterling model. Its estimate fell to 442,000 in 2025, down 7% in a year and to the lowest level since 2008. Because that measure adjusts for inflation and does not depend on the dollar exchange rate, dismissing the decline as only a currency effect would be wrong.

What the tracker cannot tell us is how many of those millionaires emigrated. The ASI identifies weaker real asset values, low saving and high-net-worth migration as contributors, but its published methodology models the total rather than observing each cause separately.

UBS can simultaneously record more US-dollar millionaires because it sets a lower, exchange-rate-sensitive threshold. Official household net worth can also rise in nominal terms while fewer people cross a demanding real-terms threshold.

The clearest conclusion is that Britain has fewer estimated real-terms sterling millionaires. The scale is modelled and the causes are contested, but the decline itself should not be waved away as a quirk of currency conversion.

Frequently asked questions

How many millionaires are there in the UK?

There is no single official current count. The Adam Smith Institute estimates 442,000 inflation-adjusted sterling millionaires in 2025, while UBS estimates approximately 2.428 million US-dollar millionaires. The figures use different thresholds and methodologies.

What counts as a millionaire in the UK?

In the Adam Smith Institute tracker, it means an adult with at least £1 million in net assets after liabilities. Property, pensions, investments and other real assets are included. It does not mean having £1 million in cash.

Why are the ASI and UBS estimates so different?

ASI measures an inflation-adjusted £1 million threshold. UBS measures a nominal US$1 million threshold and converts wealth into dollars. Currency movements, inflation treatment, datasets and modelling assumptions all affect the result.

Are UK millionaires leaving Britain?

Some wealthy residents may be relocating, and recent tax reforms could influence future decisions. However, the ASI tracker does not directly measure migration, so its 442,000 estimate cannot show how many people left the country.

This article is for general information only and does not constitute financial, investment or tax advice. Tax treatment depends on individual circumstances and can change.