From 6 April 2026 the previously unlimited 100% rate of Business Property Relief and Agricultural Property Relief is capped at £1,000,000 combined per estate, with qualifying value above the cap attracting 50% relief instead of 100%. Our Wave 2 walkthrough at April 2026 BPR/APR £1m Cap: Property Investor Impact sets out the rule, names the segments of UK landlords actually affected, and walks the planning responses. This page goes one layer deeper on the allocation question that mixed-estate families face.
The cap is straightforward on the headline. The allocation across an actual mixed estate (working farm, trading business, investment property, AIM portfolio) is not. The single £1m allowance applies jointly to BPR and APR, with the AIM 50% rate as a separate sub-tier that does not consume the allowance, and the trust anti-fragmentation rule pulling in any multi-trust structure created since the Autumn Budget 2024 announcement on 30 October 2024. The lifetime anti-forestalling rule catches large pre-commencement gifts where the donor dies post-6-April-2026. Below: the four-tier relief framework, the order-of-application question that gov.uk does not formally prescribe, a full worked allocation on the Aldridge £3.5m mixed estate, and the planning responses that move IHT meaningfully on each tier.
The four-tier relief framework after April 2026
A mixed-estate landlord may hold property across four distinct relief tiers from 6 April 2026 onwards:
- Tier 1: APR-eligible property (within £1m combined allowance). Owner-occupied farmland (and farmhouse, subject to character-appropriate use), tenanted farmland qualifying for APR at the 100% rate after the 2 or 7-year ownership conditions are met, woodland in an APR-qualifying business. 100% relief on the within-cap portion.
- Tier 2: BPR-eligible business property (within £1m combined allowance). Unquoted shares in a personal trading company, interests in a trading partnership, sole-trader trading business assets, land or buildings used in the deceased's trading business, controlling interests in a qualifying quoted-on-recognised-exchange trading company. 100% relief on the within-cap portion. The £1m allowance is shared with Tier 1 jointly; an estate with £600k of APR plus £600k of BPR fills the allowance to £1m and has £200k above-cap at 50% relief.
- Tier 3: AIM-listed shares (separate 50% sub-tier). Ordinary shares listed only on AIM (or, per the gov.uk wording, shares 'designated as not listed on the markets of a recognised stock exchange') held for at least 2 years. 50% relief from 6 April 2026, regardless of the £1m allowance position. AIM shares do not consume any part of the £1m allowance and are not eligible for the 100% rate even where the £1m allowance has not been used.
- Tier 4: Non-qualifying property (no relief). Residential BTL portfolio (Pawson v HMRC [2013] UKUT 050 (TCC) closes BPR for residential letting), light-touch short-let arrangements that do not clear the Pawson trading bar, the family home (RNRB applies but BPR does not), cash, listed shares on the main market, investment portfolios. Full 40% IHT after standard NRB and RNRB allowances.
The £1m allowance is the shared pool for Tiers 1 and 2. AIM in Tier 3 is structurally separate. Tier 4 has no relief and never had relief; the cap is silent on Tier 4.
The order of application question
The gov.uk summary of the reform establishes the £1m combined allowance and the 50%-above-cap rate but does not formally prescribe an order of application across the qualifying property within an estate. Practitioner practice fills that gap on a minimise-the-tax basis: the personal representatives compute the total IHT under alternative allocations and select the lowest.
For most mixed estates, the order does not change the total IHT, because all Tier 1 and Tier 2 property is at the same relief rate within the allowance (100%) and the same relief rate above (50%). The total £1m of relieved value is the same regardless of which qualifying assets are allocated within and which are above. Where the order matters operationally is in the practical allocation of which specific asset attracts the cap charge: families typically prefer to allocate the within-cap allowance to the most legacy-significant or most illiquid asset (the working farm) and accept the above-cap charge on the more financially flexible asset (the BPR trading business interest), so that the inheritor can sell the financially flexible asset to fund the IHT if needed.
The order does matter in two specific scenarios. First, where the estate includes both 100%-eligible property and AIM property: the AIM is on the separate 50% sub-tier regardless, so the £1m allowance is best allocated entirely to the Tier 1 and Tier 2 100%-eligible property to maximise the rate differential. Second, where there is APR-qualifying property at a 50% pre-cap rate (some tenanted farmland under FA 1995 transitional provisions can be at 50% pre-cap rather than 100%); the 50%-pre-cap APR competes with the 100%-pre-cap BPR for the cap allowance, and allocating the 100%-pre-cap property within the allowance first produces a better outcome.
Worked allocation: the Aldridge mixed estate
The Aldridge persona. A single farming-and-property estate of £3.5m at the testator's death in 2027 (i.e. post-6-April-2026). Component breakdown:
- Working farm (owner-occupied, character-appropriate farmhouse, 200 acres): £1,200,000. APR-eligible at 100% pre-cap (Tier 1).
- Property-developer special-purpose vehicle holding work-in-progress (residential development site with planning consent, £400,000 latent value): £400,000. BPR-eligible at 100% pre-cap (Tier 2).
- BTL portfolio of four residential flats: £1,600,000. No relief (Tier 4).
- AIM-listed share portfolio held for 5 years: £300,000. BPR-eligible at 100% pre-cap, dropping to 50% from 6 April 2026 (Tier 3, separate sub-tier).
Pre-cap IHT (computed as if the testator had died on 5 April 2026):
- Working farm £1,200,000 at 100% APR: £0 chargeable.
- Developer SPV £400,000 at 100% BPR: £0 chargeable.
- BTL portfolio £1,600,000: fully chargeable, £1,600,000.
- AIM portfolio £300,000 at 100% BPR: £0 chargeable.
- Chargeable estate before allowances: £1,600,000.
- NRB £325,000 plus RNRB £175,000 (single estate, simplified): £500,000.
- Net chargeable: £1,100,000 at 40% = £440,000 IHT.
Post-cap IHT (computed under the 6 April 2026 regime):
- Combined APR plus BPR pool: £1,200,000 farm plus £400,000 developer SPV = £1,600,000. Against £1,000,000 allowance: £1,000,000 within cap at 100% (£0 chargeable), £600,000 above cap at 50% relief (£300,000 chargeable).
- AIM portfolio £300,000 at 50% separate sub-tier: £150,000 chargeable.
- BTL portfolio £1,600,000 fully chargeable.
- Chargeable estate before allowances: £300,000 plus £150,000 plus £1,600,000 = £2,050,000.
- NRB £325,000 plus RNRB £175,000: £500,000.
- Net chargeable: £1,550,000 at 40% = £620,000 IHT.
Cap impact: £620,000 minus £440,000 = £180,000 of additional IHT under the post-cap regime. The £180k comes from three components: 20% effective IHT on £600,000 above-cap BPR / APR property = £120,000; 20% effective IHT on £300,000 AIM portfolio under the new 50% rate = £60,000; the £1,600,000 BTL portfolio attracts the same IHT either way (no relief either pre-cap or post-cap, so the cap is irrelevant for the BTL leg). The pre-existing BTL exposure dwarfs the cap impact on this estate; the cap adds 41% to the IHT bill but the underlying BTL exposure is the main driver.
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The anti-forestalling rule for lifetime gifts
The gov.uk summary confirms an anti-forestalling rule applying to lifetime transfers made between the Autumn Budget 2024 announcement (30 October 2024) and the 6 April 2026 commencement date. The mechanic: a lifetime gift of BPR or APR property made on or after 30 October 2024 falls into the post-cap regime if the donor dies on or after 6 April 2026 within 7 years of the gift. The relief at death-time is computed under the new £1m combined allowance plus 50%-above rates, not under the pre-cap unlimited 100% rate.
Three operational consequences:
- Lifetime gifts made before 30 October 2024 retain pre-cap treatment regardless of when the donor dies. The 7-year PET clock runs from the gift date in the normal way; full 100% BPR / APR applies at death if the donor dies within 7 years and the property was qualifying at the gift date and continued to qualify.
- Lifetime gifts made between 30 October 2024 and 5 April 2026 are caught by the anti-forestalling rule. Donors who gifted in this window expecting to lock in pre-cap treatment have been told by HMRC that they will not get it if death falls on or after 6 April 2026 within 7 years. The 7-year clock runs as normal, but the relief at death is post-cap. Donors and donees in this window should re-model the IHT exposure on these transfers.
- Lifetime gifts made on or after 6 April 2026 are within the post-cap regime by default. The forestalling rule is no longer relevant from that date onwards; the cap regime is the regime.
The forestalling rule reduces the value of a particular planning move that some landlord families made in the window since the Budget. Rolling forward to today (mid-2026), landlords considering a lifetime gift in the run-up to 6 April 2026 should compute the IHT under both regimes and confirm the gift makes sense under the post-cap regime, not just under the pre-cap regime that the gift might have been targeting.
The trust anti-fragmentation rule
The default rule is that each trust holding qualifying BPR or APR property gets its own £1m allowance for chargeable events (the 10-yearly periodic charges under s.64 IHTA 1984 and the exit charges on distributions). The gov.uk summary announces an anti-fragmentation rule for multi-trust structures: 'The government intends to introduce rules to ensure that the allowance is divided between these trusts where a settlor sets up multiple trusts on or after 30 October 2024.'
Three operational consequences:
- Trusts settled before 30 October 2024: each trust retains its own £1m allowance. The grandfathered position protects estates that had legitimately set up multi-trust structures before the Budget announcement.
- Trusts settled on or after 30 October 2024 by the same settlor: share a single £1m allowance divided across them under the anti-fragmentation rule. The precise division mechanic (per-capita, pro-rata to qualifying property value, some other rule) is in the technical consultation cycle and the Finance Act 2026 final text. The widely expected mechanic is pro-rata to the qualifying property value in each trust.
- Trusts settled by different settlors: each retain their own £1m allowance regardless of date. The rule operates on a per-settlor basis. A landlord whose adult children each settle their own trust each gets a full £1m allowance for the trust they settled, even where the trusts are economically interrelated through family ownership.
The implication: any multi-trust structure created in the planning window between the Autumn Budget 2024 and 6 April 2026 should be reviewed against the anti-fragmentation rule before it commences. Trusts that were created to multiply the £1m allowance across the same settlor may not achieve that objective; trustees should seek specialist advice and may need to consider partial decant or unwind before 6 April 2026 to clarify the post-reform position.
Planning responses by relief tier
The cap is not a single planning problem; it is four problems matching the four relief tiers, each with distinct responses:
- Tier 1 / Tier 2 above-cap (working farm or BPR business above £1m): the 20% effective IHT charge on the above-cap portion is the new exposure. Responses: lifetime gifting under s.165 TCGA 1992 holdover where available (true trading businesses qualifying for s.165 can be gifted with no immediate CGT, removing them from the estate via the 7-year PET clock); restructuring ownership across spouses to use both £1m allowances; reviewing whether multi-generational ownership structures (e.g. partial gift now plus retention of share) reduce the cap exposure at death.
- Tier 3 (AIM portfolio dropping to 50%): the AIM-as-IHT-shelter strategy is materially less effective from 6 April 2026 onwards. Existing AIM portfolios held primarily for IHT shelter should be reviewed: the after-tax position at the new 50% rate may be similar to or worse than alternative allocations (life cover in trust, charity nomination, direct gift). Selling out of AIM into other investment classes is a CGT event; the trade-off needs to be modelled on the specific portfolio.
- Tier 4 (BTL portfolio): the cap is irrelevant. The BTL is, and was, on the no-relief side of the Pawson investment line. Planning runs on the routes that have always applied: lifetime gifting (see Wave 4 C4), FIC value-freeze (Wave 4 C7), spousal exemption and second-death-window planning (Wave 4 C2), deed of variation after first death (Wave 4 C5), charitable legacy at 36% (Wave 4 C9), CLT into discretionary trust (Wave 4 C10).
- Cross-tier coordination: the single £1m allowance is shared. Couples with substantial Tier 1 plus Tier 2 exposure should consider pre-2026 ownership rebalancing so that each spouse's estate has £1m of qualifying property to use against their own allowance. The transferable mechanism that recovers wasted NRB and RNRB does not apply to the £1m BPR / APR allowance, so a wasted first-death allowance is only recoverable via deed of variation within 2 years of first death.
For the rule-impact overview and the four-segment "who is affected" framing, see Wave 2 at April 2026 BPR/APR £1m Cap: Property Investor Impact. For why pure BTL has never qualified for BPR (the Pawson investment line that closes the door regardless of the cap reform), see Why Pure Buy-to-Let Fails BPR. For the boundary case of qualifying serviced accommodation, see Serviced Accommodation and BPR. For the wider IHT planning lens, see An IHT Decision Framework for UK Landlords.
