Overseas authorities increase scrutiny of UK-based HNWIs’ assets

HMRC received 1,553 requests for information on UK taxpayers from overseas authorities in 2025, the highest level in five years, according to Lubbock Fine.

The accountancy and business advisory firm noted that overseas countries were stepping up efforts to investigate hidden offshore assets.

Lubbock Fine tax investigations director, Graham Caddock, said the bulk of the investigations targeted high net worth individuals (HNWI) who were current or former UK residents or were suspected of having hidden assets in the UK.

These assets were often hidden through complex investment vehicles, Caddock noted.

Other targets for scrutiny from foreign tax authorities included internationally mobile workers in sectors such as financial services, technology, cryptocurrency, and artificial intelligence, who were suspected of having underpaid tax for periods of time they were in the UK.

“The UK is a major hub for internationally mobile entrepreneurs and highly paid workers and the City of London is a global centre for wealth management,” Caddock said.

“That makes HMRC a key source of intelligence for overseas tax authorities to identify hidden offshore assets and unpaid income tax.

“Wealthy individuals holding assets through complex or unusual investment vehicles attract a lot of attention from foreign tax authorities.”

He added that, as many countries were looking to close deficits between their tax revenues and their expenditure, more tax inquiries were being opened both overseas and in the UK.

Additionally, as HMRC collects more data on crypto assets, it was likely to attract more requests from foreign countries on assets their citizens may have in the UK.

“Foreign tax authorities are concerned that their citizens are using cryptocurrencies to avoid taxes,” said Craddock.

“Once HMRC starts to receive data from crypto firms it seems likely that overseas tax authorities are going to start requesting this data on their tax residents who use UK-based cryptocurrency services.”

HNWIs targeted with inquiries were urged to seek advice to understand what information is reasonably required and what is not.

“There is a fine line between what information foreign tax authorities can request from UK residents and what they cannot,” Craddock stated.

“Taxpayers and especially wealthy individuals must be ready to push back if authorities overstep their mark.

“It is not unheard of for foreign tax authorities to request information that UK residents are not obliged to provide. Professional advice can help HNWs decide what information they shouldn’t disclose and help them avoid costly tax bills.”

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