Claim the Annual Investment Allowance Before Your Year-End

What Is the Annual Investment Allowance?

The Annual Investment Allowance (AIA) is a capital allowance that lets your limited company deduct 100% of the cost of qualifying plant and machinery from your taxable profits in the same accounting year you buy it. For the 2025/26 tax year and beyond, the AIA limit is £1 million per year. That is a generous allowance, and most small to mid-sized companies will never come close to exceeding it.

Without the AIA, you would instead claim writing down allowances (WDAs), which reduce the asset's value by a percentage each year — typically 18% for main pool assets or 6% for special rate assets. The AIA accelerates that relief entirely into year one, reducing your Corporation Tax bill much sooner.

What Qualifies as Plant and Machinery?

HMRC has a broad definition of plant and machinery. Qualifying items typically include:

• Computer equipment, laptops, and servers
• Office furniture and fixtures
• Machinery and tools used in your trade
• Commercial vehicles such as vans and lorries
• Business telephone systems and CCTV
• Integral features in a building, such as electrical systems, heating, and air conditioning

Notably, cars do not qualify for the AIA. They fall under their own capital allowance rules based on CO2 emissions. Purely residential property also does not qualify.

Why Year-End Timing Matters

The AIA is calculated on a 12-month accounting period basis. If your company's year-end is approaching — say, 31 July 2026 — any qualifying purchase you make before that date can be included in this year's AIA claim. Wait until 1 August and it falls into the next accounting year entirely, potentially pushing the tax relief back by 12 months or more.

Given that Corporation Tax is currently charged at up to 25% for companies with profits above £250,000, a £50,000 equipment purchase made before year-end could generate a Corporation Tax saving of up to £12,500 in this financial year rather than the next. The cashflow benefit alone makes careful timing worthwhile.

How to Actually Claim the AIA

You claim the AIA through your Company Tax Return (CT600). Your accountant will include the relevant figures in the capital allowances section of the return. Make sure you keep clear records including:

• Invoices or receipts showing the purchase date and cost
• Evidence the asset is used wholly or mainly for business purposes
• Details of any private use element, which will reduce the allowable claim

If an asset has mixed personal and business use, only the business proportion qualifies. For example, if a director uses a laptop 80% for business, only 80% of the cost can be claimed through the company.

Practical Steps to Take Before Your Year-End

If your year-end is within the next few months, here is what to do now:

• Review your planned capital spending. Is there equipment you were going to buy in the next six months? Bringing that purchase forward by even a few weeks could shift the tax relief into this year.
• Check your remaining AIA headroom. If you have already spent heavily on assets this year, confirm you have not approached the £1 million limit before committing to further purchases.
• Confirm the asset is delivered and in use. HMRC generally requires the asset to be purchased and available for use — not merely ordered — before year-end.
• Talk to your accountant. A quick conversation before you spend can confirm whether the purchase qualifies and how it affects your current year tax position.

One Final Consideration: Short Accounting Periods

If your company has an accounting period shorter than 12 months — for example, if you recently changed your year-end date — the AIA limit is reduced proportionally. A nine-month period would give you a maximum AIA of £750,000. This catches some directors off guard, so always check your actual accounting period length before planning large purchases.

Used correctly, the AIA is one of the most straightforward and valuable reliefs available to limited companies. A little planning before your year-end can bring meaningful tax savings forward and improve your company's cashflow significantly.