A controversial series of reports widely cited as evidence of a ‘millionaire exodus’ from the UK will be subject to an independent audit and review, the company behind its publication has told Spear’s.
The revelation comes as the methodology and findings of the latest edition of the Henley & Partners annual wealth migration report are under heavy scrutiny.
The report, which projected that 16,500 millionaires would leave the UK in 2025, had previously been quoted in numerous newspaper articles covering the possible consequences of changes to the UK’s tax regime.
Since the start of the year, the Times, for example, has published 15 articles that refer to reports by Henley & Partners or the research firm that carries out the work that underpins its reports, New World Wealth. Headlines include ‘Why a wealth tax won’t work’ and ‘Why the super-rich are leaving Britain’.
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However, following analysis of data included in the 2025 wealth migration report, Tax Policy Associates, a respected think tank, published an article which claimed the ‘Henley & Partners reports can’t be trusted . . . and until an independent audit is carried out should be treated as marketing material, not evidence’.
Speaking exclusively to Spear’s, Henley & Partners and New World Wealth have defended the reports, saying that recent criticisms ‘appear to stem more from the politicisation and misuse of the data’.
Tax Policy Associates says it found a number of problems with the report findings. One is that a decision to remove property assets from wealth estimates from 2023 to 2025 did not appear to affect the figures in the way one might expect.
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The think tank also claims numbers contained within the reports rely too heavily on LinkedIn data to be a reliable reflection of individuals’ tax residencies. ‘Strikingly, the report’s methodology states that its estimates are primarily a measure of where millionaires say they work on social media and not where they live or reside, meaning the report does not track actual, physical migration — contrary to the presenting of the estimates,’ said the critique.
The think tank has additionally criticised the Henley and New World Wealth data for containing too many even numbers. It says the chance of such a distribution of figures occurring naturally is just 2 per cent, suggesting that this is ‘classic evidence of numbers typed, not measured’.
Tax Policy Associates has also questioned whether it is realistic for just one person to be able to ‘track’ the vast quantities of data that are said to feed into the reports.
New World Wealth, based in South Africa, is a one-man band, run by founder and sole employee Andrew Amoils, who puts together the data for numerous Henley & Partners reports. Tax Policy Associates says: ‘A one‑man firm says it tracks 150,000 fortunes — right down to investments, cash and crypto — and nets off their debt. That simply can’t be done.’
Dan Neidle, founder of the think-tank, told Spear’s: ‘Speaking to people in the private wealth industry — private bankers and advisers — many told us the figures seemed off. I don’t believe there’s any way to produce international tables with that level of detail across countries and cities. The very large and able teams at UBS, Capgemini, and Knight Frank [which compile detailed reports about the behaviour of wealthy people] have never come anywhere close to this. Public sources just don’t have the information.’
Others agree. Isaac Delestre, a senior research economist at the respected Institute for Fiscal Studies, said: ‘There is no high-quality evidence that I know of that allows us to track the movements of high wealth or high-income individuals yet available.’
Both Henley & Partners and New World Wealth dispute the accusations.
Henley & Partners told Spear’s that it has always accepted the figures provided by Amoils in good faith and that it has had no reason to question their legitimacy, adding that the research outcomes have been consistent with trends observed from its own client base.
‘Unfortunately, recent criticisms appear to stem more from the politicisation and misuse of the data rather than from flaws in its underlying methodology,’ the consultancy said in a statement.
‘The figures were never intended to support highly specific claims, such as the exact number of millionaires leaving the UK in response to particular government policies.’
Henley & Partners said its reports are meant to be indicative of what is happening in terms of migration, rather than including precise numbers. ‘They serve as indicators of broader trends, much like academic modelling exercises that, while imperfect, offer valuable directional understanding,’ it said.
A look back at previous Henley & Partners wealth migration reports shows that they describe figures about future movements of millionaires as ‘projections’, but that the company also presents data from the past as if it were factual. Although presented in one instance under the heading ‘illustrative data’, a description of the figures reads: ‘The data shows the total number of millionaires who have moved to a new country each year since 2013, based on those who have relocated and remained for longer than six months.’
Speaking to Spear’s from Johannesburg, the first time he has responded to the Tax Policy Associates criticism publicly, Amoils said: ‘I completely stand by my data.’
In response to the claims made about the removal of property wealth from the methodology, Amoils said that only a very little amount of debt-free investment property was included previously and so the ‘impact of stripping it out was small’.
On being the only person at his firm, Amoils said: ‘The “one-man firm” argument sounds good in print. However, the truth is even the big market research houses of 500 plus employees don’t put their whole team on a wealth report. They would typically put three people max.’
He added that the quantity of even numbers was a consequence of the rounding system he employed, where figures are rounded to the nearest 50, 100 or 1,000 depending on the report. ‘It is important to remember that our figures are not exact, they are modelled estimates, which is why we round them,’ he says.
And in reference to his use of LinkedIn, Amoils reiterated: ‘We stand by the strength and credibility of our migration report methodology, including the use of LinkedIn data. Over 70 per cent of the world’s CEOs maintain active profiles on the platform, making it a valuable and relevant source. LinkedIn also gives a city location for each person, which is very useful.’
For now Henley & Partners says it will continue to use Amoils’ figures and that it is ‘committed to’ delivering two annual studies in the next six weeks — the 2025 Africa wealth and crypto wealth reports — which are already in advanced stages of production.
However, the firm added: ‘In light of the concerns raised we have already initiated an independent audit and review of New World Wealth’s methodology and data — a process to which New World Wealth has willingly agreed. The findings from this review will inform any decisions on the future of the partnership.’
Spear’s understands changes could include publishing more details about the methodology, narrowing the scope of the reports, and making sure that any limitations are clearly outlined.
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Tax Policy Associates would welcome any such move but until then, its founder believes the numbers simply do not add up. ‘We believe Henley & Partners should withdraw their reports until they have been audited by a suitably qualified independent third party,’ said Neidle. ‘In the meantime, they shouldn’t be relied upon by policymakers, journalists, or anyone seeking to understand global wealth or migration trends.’
The confusion concerning the Henley reports has clouded the debate around new tax policies introduced by the Labour government and chancellor Rachel Reeves, including the move to alter the UK’s non-dom rules.
In a post on LinkedIn, James Quarmby, founding partner of the private wealth division at law firm Stephenson Harwood, wrote: ‘Labour supporters will love this story as it appeals to their denialist tendencies. However, the New World Wealth survey was only one of quite a few which have given the same message — that the migration of wealthy people has accelerated alarmingly.’
According to an analysis of Companies House filings by the Financial Times, 3,790 company directors reported leaving the UK between last year’s October Budget and July – a 40 per cent increase compared with the same period a year earlier.
Another analysis of Companies House filings by Bloomberg found that the number of company directors changing their country of residence from the UK to another jurisdiction in April of this year was up 75 per cent on the previous year’s figure.
