Selling Your Home to Children Below Market Value: The Hidden Inheritance Tax Risk

How HMRC treats a below-market sale

Under HMRC guidance, selling a property to a family member for less than its open market value is not treated as a simple sale. The difference between the price paid and the true market value is classified as a gift — and gifts carry inheritance tax implications.

If you sell a property worth £500,000 to your child for £300,000, HMRC treats the £200,000 difference as a gift made on the date of the transaction. That gift starts a seven-year clock. If you die within seven years, the gift may be added back to your estate for IHT purposes, potentially attracting tax at 40% — in this example, up to £80,000 in additional IHT liability.

Taper relief applies on a sliding scale if death occurs between three and seven years after the gift, but the liability does not disappear until the full seven years have elapsed.

The Gift with Reservation of Benefit trap

The risk is compounded significantly if you continue to live in the property after the sale. HMRC applies what is known as the Gift with Reservation of Benefit (GWR) rule: if you transfer or sell a property at below market value and then continue to occupy it without paying a full market rent to the new owner, the property is treated as remaining within your estate for IHT purposes — indefinitely, regardless of when the transaction took place.

This is one of the most common and costly planning errors HMRC encounters. Families believe a below-market sale has reduced the estate, when in reality the property has never left it for IHT purposes. The seven-year clock does not even begin to run while the reservation of benefit persists.

To escape GWR treatment, the original owner must either vacate the property entirely or pay a full commercial market rent to the new owner — which itself has income tax consequences for the recipient.

HMRC's reach: investigation windows and rising scrutiny

HMRC can investigate property valuations for up to four years after the relevant transaction. Where there has been carelessness in the valuation, that window extends to six years. For deliberate undervaluation, HMRC has up to 20 years to investigate and recover tax owed.

The scale of scrutiny is increasing. IHT referrals to the Valuation Office Agency — the body that assesses whether property has been correctly valued for tax purposes — rose by 23.5% to 14,631 in the year to September 2025. HMRC is actively challenging valuations, and the resources allocated to this work are growing.

From April 2026, Agricultural and Business Property Relief has been capped at £2.5 million per individual for 100% relief, with 50% relief applying above that threshold. This change has increased the IHT exposure of many estates and raised the stakes on accurate planning.

An alternative approach: equity release

For homeowners who want to help their children financially without triggering gift treatment, a seven-year clock, or potential GWR complications, equity release offers a different path.

By releasing equity from your home through a lifetime mortgage, you could access a lump sum that you are free to gift to your children. This gift is made in cash rather than in property, which avoids the GWR rules entirely — you remain the legal owner of your home and continue to live in it. The cash gift still starts a seven-year clock for IHT purposes, but the property itself is not implicated.

Additionally, the outstanding equity release loan reduces the value of the estate at death, since it is secured against the property and repaid on sale. This can have a meaningful effect on the overall IHT calculation.

Equity release is subject to FCA-regulated advice and is not appropriate for everyone. There is no obligation to proceed, and a qualified adviser will assess whether it is suitable for your circumstances — taking into account your age, health, property value, existing mortgage, and estate planning objectives.