Business Property Relief's New £2.5 Million Cap: What Actually Changes for Property Businesses

From 6 April 2026, unlimited 100% Business Property Relief is gone. In its place is a £2.5 million combined allowance, shared with Agricultural Property Relief, above which relief drops to 50%. It is a genuine change for family trading businesses that will one day pass through an estate — but it changes almost nothing for the average buy-to-let landlord, because their portfolio was very unlikely to have qualified for the relief in the first place.

What actually changed on 6 April 2026

The reform, first announced at Autumn Budget 2024, restricts the 100% rate of Business Property Relief (BPR) and Agricultural Property Relief (APR) to a combined allowance per estate. Above that allowance, relief drops to 50% — an effective 20% Inheritance Tax rate on the excess, since the standard rate is 40%. Below the allowance, qualifying business and agricultural property remains entirely free of Inheritance Tax, exactly as before.

The allowance applies to property held at death together with any taxable gifts made in the seven years before death, and the government has built in an anti-forestalling rule: the new cap can apply to lifetime gifts made on or after 30 October 2024 if the donor dies on or after 6 April 2026 but within seven years of the gift. Restructuring the ownership of a family business is not, in other words, a one-afternoon fix — the clock on any gift only started running from the date it was made, and only escapes the cap entirely if the giver survives seven years or the reform's start date, whichever is later.

The allowance's back story: £1 million became £2.5 million

The figure originally announced in October 2024 was £1 million, and it was proposed as non-transferable between spouses — a couple would effectively have had two separate £1 million allowances that could not be combined on second death, unlike the nil-rate band. That original design drew sustained criticism from family business and farming groups, and in December 2025 the government amended it: the allowance increased to £2.5 million, and any unused portion became transferable between spouses and civil partners, mirroring how the residence nil-rate band already works. A couple can now shelter a combined £5 million of qualifying business and agricultural property at the 100% rate before the 50% rate bites, on top of their ordinary nil-rate bands.

It is worth being precise about this history when you read older commentary or your own previous notes on the subject — a lot of planning was modelled against the original £1 million, non-transferable figure before the amendment, and that modelling is now out of date.

Why most landlords are unaffected either way

The cap only matters for property that already qualifies for BPR, and most rental property never did. Relief specifically excludes a business that consists wholly or mainly of holding investments, and HMRC's long-standing position — upheld in tribunal cases including Pawson v HMRC and Green v HMRC — is that letting property is an investment activity rather than a trade, however actively it is managed. That test is untouched by this reform. If your rental portfolio did not qualify for BPR before 6 April 2026, the £2.5 million allowance gives it nothing to work with. We cover the planning that actually helps a letting portfolio in our guide to Inheritance Tax planning for property landlords.

Who this genuinely matters to

The cap is relevant to businesses that were already trading in HMRC's eyes: a construction or development company that builds and sells rather than lets, a genuinely trading serviced accommodation business run with hotel-level services, or a family business where property is incidental to a wider trade. For these businesses, shares in a private trading company are “relevant business property” and previously attracted unlimited 100% relief. That relief is now capped at £2.5 million combined with any agricultural property in the estate, with the excess taxed at an effective 20% rather than being fully sheltered.

A family-run development business built up over decades, held through a single trading company or a group, is exactly the kind of asset where this bites. The company's value is often concentrated in land and work in progress that has appreciated well beyond what the founders expected when they started — and a value that comfortably cleared £1 million (and now needs to clear £2.5 million, or £5 million for a couple) to trigger the 50% rate is not unusual for an established regional developer.

AIM and other unquoted-market shares are treated differently

Shares quoted on AIM and similar growth markets (as distinct from the main market, where BPR was never available) sit outside the £2.5 million allowance altogether. From 6 April 2026 they receive a flat 50% rate of relief regardless of value — they do not draw on the allowance, and they cannot benefit from the 100% rate at all, however small the holding. This distinction matters if part of a family's planning has involved AIM portfolios specifically because of their previous 100% relief; the calculus for that strategy has changed independently of the wider cap.

The trading test hasn't moved

None of this changes the underlying qualifying conditions for BPR. The business (or the company whose shares are held) still has to be a trading business, not one that is wholly or mainly holding investments, and HMRC still looks at the balance of activities, assets, income and time in making that judgement. A family investment company that holds a mix of development activity and long-term lettings can find itself on the wrong side of that line even before the £2.5 million question arises — a point worth reading alongside our guide to Family Investment Companies for a property portfolio if a group structure of yours mixes both activities.

Planning implications for family property trading businesses

• Revisit any modelling done before December 2025. Plans built around a non-transferable £1 million figure are likely to reach a different conclusion under the transferable £2.5 million allowance.
• Think about how ownership is split between spouses. Because the allowance is now transferable, the planning premium on lifetime equalisation between spouses specifically to use two allowances has fallen — though other reasons for that equalisation, such as income tax, may still apply.
• Consider whether an eventual sale, rather than a bequest, is the more likely outcome. If the business is destined to be sold rather than passed down, the relevant question shifts from Inheritance Tax relief to whether a disposal could benefit from the Substantial Shareholdings Exemption, which is a separate corporation tax relief with its own, quite different, trading test.
• Value the business properly, and revisit that valuation periodically. Whether an estate sits above or below £2.5 million (or £5 million with transferability) is a valuation question as much as a legal one, and property-heavy trading businesses can move across that line quickly as land values shift.

Common mistakes

• Assuming the reform helps a letting or investment portfolio — it doesn't touch the trading test that excludes most rental property from BPR in the first place
• Planning against the original October 2024 figures rather than the amended December 2025 allowance
• Treating AIM holdings the same as unquoted trading shares when they now sit under a different, less generous rule
• Leaving succession planning until later in life, when the seven-year and anti-forestalling rules leave less room to manoeuvre

This is a case where the right structure and the right timeline depend heavily on the specific business, its trading mix, and what the next generation actually wants. It is worth a conversation under our Property Advisory service well before any succession event, rather than after one.

Common questions

Does Business Property Relief still apply to my rental portfolio?

Almost certainly not, and this is unchanged by the April 2026 reform. Business Property Relief excludes businesses that consist wholly or mainly of holding investments, and HMRC treats letting property as an investment activity rather than a trade, however actively it is managed. The £2.5 million cap only matters for businesses that already qualified for relief — it does not extend relief to portfolios that never qualified.

What is the new £2.5 million Business Property Relief allowance?

From 6 April 2026, the first £2.5 million of combined agricultural and business property in an estate continues to receive 100% relief from Inheritance Tax. Value above that threshold receives 50% relief, giving an effective 20% tax rate on the excess. The allowance was originally proposed at £1 million at Autumn Budget 2024, then increased to £2.5 million in a December 2025 amendment.

Is the £2.5 million allowance transferable between spouses?

Yes. Following the December 2025 amendment, any unused part of the allowance can transfer to a surviving spouse or civil partner on death, similar to how the residence nil-rate band works. A couple can therefore shelter a combined £5 million of qualifying agricultural and business property at the 100% rate before the 50% rate applies.

How are AIM shares treated under the new Business Property Relief rules?

Differently to other qualifying business property. From 6 April 2026, shares quoted on AIM (and other recognised growth markets, as opposed to the main market) receive a flat 50% rate of relief regardless of value, and do not draw on the £2.5 million allowance at all. That allowance is reserved for sole trades, partnership interests, unquoted trading company shares and qualifying agricultural property.

This article is general information, not personal tax advice, and tax rules change. Your own position depends on facts we cannot see from here — please take advice before acting on anything above.

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