HMRC has given every UK billionaire a named handler. Advisers are asking what it is entitled to see.

HM Revenue and Customs wrote over the summer of 2026 to every billionaire it considers to have a UK tax footprint, appointing each of them a customer compliance manager. On 24 September 2026, Bloomberg Tax reported that it had seen extracts of those letters, and that advisers to the recipients were declining to answer parts of them.

The letters ask for a full picture of a person’s financial life: business interests, investments, property, trusts, company assets, other sources of income and gains, and the structures that hold them. HMRC has offered something in return. Billionaires who cooperate are promised a more joined-up service, fewer duplicated information requests, conversations confined to areas of genuine uncertainty or risk, and earlier discussion of transactions before returns are filed.

Why this is happening now

The exercise follows a finding by a cross-party parliamentary committee last year that HMRC had an incomplete grasp of billionaires’ affairs, to the point of not knowing how many of them paid tax in the UK. HMRC has since widened its own definition of a UK billionaire to take in people holding wealth through offshore structures or property, rather than only those who file a UK return, and is identifying the population using its own data, public information and data shared by other tax authorities.

Compliance managers are not new. HMRC has allocated them to wealthy individuals for years. What is new is treating billionaires as a distinct cohort and approaching all of them at once.

Where advisers are drawing the line

The objection reported is narrow and technical rather than a refusal to engage. Practitioners quoted by Bloomberg Tax questioned the statutory basis for some of the requests, on the view that outside a formal enquiry the scope of what HMRC may ask is limited. Christopher Groves of Withers said clients were largely responding politely and declining, and described a request for a client’s business succession plans as “a definite step too far”. Charlie Sosna of Mishcon de Reya said several billionaire clients had been contacted and that some were taking advice on what they are legally obliged to hand over.

Not everyone reads it that way. Edward Troup, a former executive chair of HMRC, argued that full disclosure of the arrangements behind income, gains and tax management is the reasonable price of the relationship, and that refusal invites deeper enquiry.

The timing is awkward. The approach lands after several years of tax changes that have already moved people out of the country, most recently the hedge fund manager Chris Rokos, who announced a departure for Greece earlier in September.

What it means for family offices

For a family office, this is an operational question before it is a legal one. A request of this breadth cannot be answered from a set of tax returns; it requires a current, consolidated view of entities, holdings and beneficial ownership across jurisdictions, and most offices will discover how far they are from having one only when they try to assemble it. Families whose structures were built for confidentiality rather than for explanation will find the second harder than the first.

The second point is about who answers. Where the request touches governance and succession rather than tax computation, the choice of what to volunteer is a family decision that needs a single adviser holding the line, not four professionals responding separately. Getting advice before replying, rather than after, is the practical lesson advisers are drawing from the first round of letters.

Sources: Bloomberg Tax; The National; WealthBriefing.