HMRC inheritance tax underpayment by wealthy individuals has reached a suspected £392m for the year to 31 March 2026, a rise of 14% from £344m a year earlier, according to TWM Solicitors, and that figure sits within a broader picture of intensifying HMRC enforcement that investors and executors would do well to take seriously.
For savers approaching retirement or managing an estate, the direction of travel here matters as much as the headline number. HMRC’s analytical capabilities are expanding, and the agency’s definition of ‘wealthy’ is wider than many assume. According to Money Marketing, HMRC classifies someone as wealthy if they have income of at least £200,000 or assets worth more than £2m in any of the previous three years, a threshold that catches a sizeable proportion of SIPP holders, property owners and business proprietors who may not think of themselves as particularly affluent.
Where HMRC Is Looking for HMRC Inheritance Tax Underpayment
TWM Solicitors identified the key areas drawing HMRC attention: probate valuations, gifts, overseas accounts, cryptocurrency, business relief and undeclared assets. Executors who underpay face interest charges and penalties. TWM’s advice is direct, obtain robust professional valuations, maintain thorough records and seek specialist guidance early, before discrepancies come to the agency’s notice rather than after.
The crypto angle deserves particular attention from anyone holding digital assets as part of a diversified portfolio. According to the BBC, HMRC sent 81,172 warning letters, emails and text messages to crypto investors it suspects may have underpaid tax in the 2025-26 financial year alone. That scale of outreach signals an agency that is no longer treating cryptocurrency as a fringe concern.
Broader Context: IHT Receipts, Pension Reform and Estate Planning
The underpayment figure arrives alongside HMRC’s overall tax collection data, which shows inheritance tax receipts reaching £3.8bn between April and August. Total HMRC revenues across tax and national insurance contributions came to £391.6bn over that period, £24.9bn more than a year earlier. Frozen thresholds are doing much of the work here, drawing more families into the IHT net without any change in headline rates.
Against that backdrop, Royal London has launched a dedicated estate planning framework designed to help advisers prepare clients for the point at which unused pension funds enter the inheritance tax net from April 2027. Lead actuary Ken Scott described effective wealth transfer as requiring structured and repeatable processes. For anyone managing a SIPP or SSAS with the intention of passing residual assets to the next generation, that deadline represents a genuine planning horizon worth addressing now rather than closer to the date.
The pension angle extends beyond IHT. Research from Aberdeen Adviser found that 96% of advisers are spending more time reassuring clients about possible pension tax changes ahead of the Budget, with tax-free cash the primary concern. Aberdeen warned that early withdrawals can trigger irreversible consequences, including HMRC recycling rules and the £10,000 money purchase annual allowance, a point that underlines why the accumulation and decumulation phases of retirement planning cannot be considered in isolation from the prevailing tax environment.
For the capital gains tax picture, HMRC collected £198m in August, slightly above the prior year, though overall CGT receipts since April are running lower. Commentators have cautioned that further rate increases could alter investor behaviour, a sequence-of-returns risk in its own right if clients begin restructuring portfolios in response to tax rather than investment logic.
Taken together, these developments point to a planning environment in which HMRC is both better equipped to identify underpayment and increasingly motivated to act on it. Executors, pension holders approaching drawdown and investors with crypto or overseas exposures each face specific compliance considerations that professional advice, early documentation and regular portfolio review can help address before enforcement correspondence arrives.
