Business Property Relief on AIM Shares: IHT Planning 2026/27

Why AIM shares became a popular IHT planning tool

Business Property Relief (BPR) exists to reduce or remove Inheritance Tax on genuinely trading business assets, recognising that forcing a family to sell a business to pay an Inheritance Tax bill would often be destructive. While BPR is most naturally associated with unquoted family companies, it also extends to many shares listed on the Alternative Investment Market (AIM) — because AIM, despite being a public market with its own listing rules, is specifically not treated as a "recognised stock exchange" for BPR purposes. This quirk means qualifying AIM shares can benefit from the same relief as genuinely unquoted trading company shares, while still being tradeable on a public market — a combination that made AIM BPR portfolios a popular later-life Inheritance Tax planning tool, since the shares can be bought, held for the qualifying period, and sold relatively easily if circumstances change.

The two-year holding rule

To qualify, the shares generally need to have been held for at least two years before the death of the owner (with some special rules allowing continuity of ownership periods where one qualifying business asset directly replaces another). This is considerably shorter than the seven-year survival period required for a potentially exempt transfer to become exempt, which is part of why AIM BPR portfolios have appealed particularly to older investors who may be concerned about surviving a full seven years for other forms of gifting.

Crucially, the qualifying status must also be maintained at the date of death, not just at the point of purchase — if the underlying company changes its business so substantially that it no longer counts as a genuine trading company (for example, becoming primarily an investment or property-holding vehicle), the shares can lose their relief entitlement even if they qualified when originally bought.

What does not qualify

Not every AIM-listed company automatically qualifies for BPR. The relief specifically excludes companies that are mainly investment businesses, or that hold a significant proportion of value in non-trading assets — such as large cash reserves beyond working capital needs, investment property, or securities held as investments rather than for trading purposes. This is a genuinely important distinction: simply buying any AIM-listed share does not guarantee BPR eligibility, and specialist AIM IHT portfolio services generally screen holdings specifically to focus on companies most likely to maintain qualifying trading status.

The new cap from April 2026

A significant change affects how valuable this relief now is for larger portfolios. From April 2026, most previously 100%-relieved business and agricultural assets — including qualifying AIM shares — are subject to a combined allowance that gives full 100% relief only on the first £1 million of combined qualifying value per person. Value above that £1 million threshold receives only 50% relief, meaning the effective Inheritance Tax rate on the excess is 20% (half of the standard 40% rate) rather than 0%.

Illustrative example: An investor holds £1.5 million in qualifying AIM shares (with no other qualifying business or agricultural assets) at death. The first £1 million qualifies for 100% relief (no Inheritance Tax on that portion). The remaining £500,000 qualifies for only 50% relief, meaning £250,000 of that amount is effectively taxable, creating an Inheritance Tax charge of £100,000 (40% of £250,000) — where previously, before the cap, the entire £1.5 million might have been fully relieved.

The genuine risks, beyond the tax rules

It is important not to treat an AIM BPR portfolio purely as a tax-planning mechanism — the underlying investments carry real commercial risk:

• Volatility: AIM shares are typically smaller, higher-risk companies than those on the main market, with share prices that can move sharply.
• Liquidity: some AIM stocks trade thinly, meaning it can be harder to sell a large holding quickly without affecting the price.
• Loss of qualifying status: a company's business can change over time in ways that jeopardise its BPR eligibility, independent of its share price performance.

Practical takeaway

AIM Business Property Relief portfolios remain a legitimate and relatively fast-acting (two-year, rather than seven-year) Inheritance Tax planning tool, but the April 2026 cap on 100% relief has meaningfully reduced their effectiveness for larger estates, and the underlying investment risk — volatility, liquidity, and the possibility of a company losing qualifying status — should be weighed just as carefully as the tax benefit itself before committing significant sums.