The number of new investigations into underpaid inheritance tax has jumped by 33% in three years, a Freedom of Information request by NFU Mutual has revealed.
According to FOI data, the number of investigations by HM Revenue & Customs into estates where inheritance tax is suspected to have been underpaid rose from 3,163 in 2022-23 to 4,200 in 2024-25.
The data showed a sharp rise in the number of new investigations launched this current tax year. A total of 3,636 probes were opened between April and December 2025, accounting for almost a quarter of the 14,000 IHT investigations opened since April 2022.
NFU Mutual warned that with more families set to be dragged into the inheritance tax net in the coming years, there is likely to be a rise in the number of investigations launched.
The Office for Budget Responsibility estimates that 9.5% of deaths could trigger inheritance tax bills by 2029-30, up from 5.1% in 2022-23.
Inheritance tax paid by families between April 2025 and December 2025 totalled £6.6 billion, some £0.2 billion higher than for the comparative period in 2024, according to government data.
Sean McCann, chartered financial planner at NFU Mutual, said: “Where there is a suspicion that inheritance tax has been underpaid through error, omission, or undervaluing assets, HMRC has substantial investigatory powers and will check a range of sources to build a picture of the deceased individual’s financial affairs.
“In addition, the interest rate you pay on overdue inheritance tax stands at 7.75% which can add a significant amount to the bill. This can compound what for many is already a challenging and distressing situation.”
McCann said the significant revenue recovered through these investigations and the rising value of assets and potential sums at stake would “appear to justify HMRC increasing the number of cases they look at.”
He added: “IHT remains one of the most feared and least understood taxes. With unspent pensions falling within the inheritance tax net from 2027 and many farms and businesses from April 2026, more and more families will find themselves dragged into paying inheritance tax.”
Main image: markus-winkler-afW1hht0NSs-unsplash
