Key Takeaways

• The Annual Investment Allowance provides 100% tax relief on qualifying plant and machinery expenditure up to £1 million per year. It has been permanently set at this level since April 2023.
• Cars, land, buildings, and assets already owned by connected parties do not qualify for AIA. Cars enter capital allowances pools based on CO2 emissions.
• Connected businesses must share the £1 million AIA limit. Two companies under common control have a combined cap of £1 million, not £1 million each.
• Integral features — electrical, heating, ventilation, cold water systems, and lifts — in commercial buildings qualify for AIA and should not be treated as structural expenditure.
• Zero-emission cars and vans attract a 100% first-year allowance separately from the AIA. This relief sits outside the £1 million cap and does not consume the AIA limit.
• For short accounting periods, the AIA is proportionally reduced. A six-month period has an AIA of £500,000.
• The AIA cannot be deferred — it must be claimed in the period the expenditure is incurred. Failure to claim in the correct period means the opportunity is permanently lost.

FAQs

Q1: Can a sole trader claim AIA on equipment purchased in the final weeks of their accounting year if the invoice has not yet been paid?

A1: Well, it is worth noting that the timing of an AIA claim depends on when the expenditure is incurred — not when it is paid. For most purchases, expenditure is incurred when the unconditional obligation to pay arises, which is typically when the contract is entered into or when the goods are delivered and title passes, whichever is later under the terms of the agreement. A sole trader who orders and receives equipment in late March, with an invoice dated in March that they pay in April, has incurred the expenditure in March — and that expenditure falls in the accounting period ending 5 April. The fact that payment follows in the next tax year does not push the expenditure into the later period. This distinction matters enormously when a business is trying to accelerate AIA claims into the current year. Conversely, equipment ordered and paid in March but not delivered until April is typically incurred in April when delivery and title transfer occur. The safest approach is to ensure both delivery and the contractual commitment occur before the year end where current-year AIA is needed. Keeping the delivery note, invoice, and purchase order dated consistently in the same period is good practice for avoiding any HMRC challenge on timing.

Q2: Does AIA apply to assets a business owner contributes from their personal ownership into a partnership or limited company?

A2: In my experience, this is one of the most frequently misunderstood aspects of AIA eligibility, and it catches business owners at the point of incorporation or when formalising a partnership. The AIA is available only on new expenditure — that is, money spent acquiring the asset from an unconnected third party during the accounting period. When a sole trader incorporates and transfers personally-owned assets into a new limited company, those assets enter the company’s capital allowances pool at their market value. However, because the transfer is between connected parties rather than a new purchase from the market, AIA cannot be claimed on that value. The same applies to a partner introducing assets into a partnership. The assets are eligible for writing-down allowances at the normal pool rates — 18% for main pool assets — but the AIA 100% first-year deduction is not available. This means a business owner who has, say, £80,000 of machinery that they transfer to a newly incorporated company at market value will receive only the first-year writing-down allowance of £14,400, not the full £80,000. Planning the timing of major asset purchases — buying directly through the company rather than personally and then transferring — avoids this problem entirely.

Q3: Can a landlord with a residential rental property claim AIA on furniture and white goods supplied to tenants?

A3: Well, this is an area where the rules are quite specific and where landlords often make costly assumptions. Residential landlords cannot claim AIA on assets they provide to tenants. Instead, they have access to the replacement of domestic items relief, which allows the cost of replacing existing items — furniture, appliances, curtains, soft furnishings — to be deducted against rental income in the year of replacement. The key word is replacement: this relief does not apply to furnishing a property from scratch, only to replacing existing items with equivalent ones. It is a revenue relief, not a capital allowance, and it sits within the rental income calculation rather than the capital allowances regime. For landlords who also operate furnished holiday lets, the position was different — FHLs did qualify for capital allowances including AIA on furniture and equipment. However, the FHL regime was abolished from April 2025, and from that date, former FHL properties are treated as standard residential lettings for tax purposes, which removes the AIA entitlement. Commercial landlords — those letting properties to businesses — can claim AIA on plant and machinery installed in their commercial properties, including integral features. The residential versus commercial distinction is therefore the starting point for any landlord wondering about capital allowances.

Q4: How does AIA work for a partnership where the partners have different profit-sharing ratios, and who claims the relief?

A4: Well, this is an area that trips up many partnership accountants. The AIA belongs to the partnership as a business entity, not to the individual partners in proportion to their profit shares. The partnership claims AIA in the partnership tax return, and the allowance reduces the taxable profit of the partnership as a whole. That reduced profit is then shared between partners according to their profit-sharing ratio for the period. So if a partnership spends £200,000 on equipment and claims £200,000 of AIA, the entire £200,000 reduces partnership profit before it is split. A partner with a 30% share benefits from 30% of the AIA-generated reduction — they are not entitled to their own separate AIA claim on top of the partnership’s claim. Where multiple partnerships are connected — for example, two farming partnerships with overlapping partners — the connected party rules require them to share the £1 million AIA limit. The allocation of the shared limit between the two partnerships is a matter for the partners to agree, but HMRC must be notified of the allocation if both partnerships are claiming AIA. In practice, the allocation should favour the entity with the higher corporation tax or income tax rate on its profits, to maximise the tax value of the relief used.

Q5: Is the AIA available on the purchase of a commercial property that includes plant and machinery, and how should the purchase price be split?

A5: In my experience, commercial property purchases are one of the most significant AIA opportunities that businesses fail to exploit fully, and the split of the purchase price is the critical exercise. When a business buys a commercial property, the purchase price covers land (no allowances), the building structure (SBA only at 3%), and embedded plant and machinery — primarily integral features such as electrical systems, heating, ventilation, and cold water systems. The portion of the purchase price attributable to qualifying plant and machinery can be claimed under AIA in the year of purchase, giving 100% immediate relief on that element. The challenge is establishing what proportion of the price relates to each category, and this requires a formal capital allowances survey by a surveyor or specialist adviser. The split is not arbitrary — it must be agreed with the seller at the point of sale through what is called a section 198 election, which fixes the values attributed to each category of allowance for both parties. If no section 198 election is made, the default rules apply and HMRC may dispute the split later. For a commercial property purchase of £500,000, a properly conducted survey might identify £80,000 to £120,000 of embedded plant and machinery — giving AIA relief worth between £15,200 and £22,800 at 19% corporation tax, or considerably more at 25%.

Q6: Can a business claim AIA on a second-hand asset purchased from an unconnected seller, and does it matter that the asset is not new?

A6: Well, it is worth noting that AIA is not restricted to new assets — it applies to second-hand plant and machinery purchased from unconnected parties in exactly the same way as brand-new equipment. A manufacturing company that buys a used lathe from another business for £40,000 can claim the full £40,000 under AIA in the year of purchase, provided the asset qualifies as plant or machinery and the seller is not a connected party. The condition that prevents AIA on second-hand assets is connection, not age. If a business buys used equipment from its own director, a connected company, or a related family member, AIA is not available and the asset enters the writing-down allowance pool instead. For an unconnected third-party seller — a liquidation sale, an auction, a trade-in arrangement, or a private sale — the AIA applies in full. This creates a planning opportunity for businesses looking to acquire well-maintained used equipment at below-new prices: the tax relief is identical to buying new, while the cash outlay is lower. One practical point to note: where an asset was previously used in a business for which capital allowances were already claimed, the seller’s allowances position is closed out on disposal, and the buyer starts fresh with their own AIA claim on the price they paid.

Q7: Does the AIA apply to software purchased by a business, and is there a distinction between off-the-shelf software and bespoke development?

A7: Well, this is genuinely one of the more technically nuanced areas of capital allowances, and the answer depends critically on the type of software involved. Off-the-shelf software — commercial products purchased or licensed for use in the business — is generally treated as plant and machinery and qualifies for AIA. This includes business software packages, subscription software that involves an upfront licence cost, and similar commercial products that a business buys to use as a tool in its trade. Bespoke software developed specifically for a business — commissioned development costs, internal development staff costs, and similar — is treated differently. Development costs of this nature may be treated as capital expenditure on an intangible asset rather than plant and machinery, in which case they fall under the intangible assets regime rather than capital allowances, and AIA does not apply. The distinction is whether the software results in the acquisition of a separate identified asset (bespoke development, likely intangible) versus the purchase of a tool or product (off-the-shelf, likely plant). The Research and Development tax relief regime can interact with software development costs for qualifying businesses, providing an alternative route to relief. A business investing heavily in software should review whether each category of expenditure falls under AIA, the intangibles regime, or R&D relief — they are not interchangeable and can produce very different relief amounts and timings.