What Is the Annual Investment Allowance?
The Annual Investment Allowance (AIA) lets you deduct the full cost of qualifying plant and machinery from your taxable profits in the year you buy it. For the 2025/26 tax year, the AIA limit is £1,000,000. That is a generous cap. Most small and medium businesses never hit it.
The key question business owners ask is whether this applies to second-hand assets. The short answer is yes, in most cases. But there are specific rules and exclusions you need to know before you claim.
Can You Claim AIA on Second-Hand Assets?
Yes. The AIA is not restricted to new assets. If you buy used plant or machinery for your business, you can claim the AIA on it, provided the asset qualifies as plant and machinery under capital allowances rules.
This is a common misconception. Many business owners assume the AIA only applies to brand-new equipment. That is not correct. A second-hand forklift, a used lathe, a pre-owned van, or refurbished IT equipment all qualify, as long as they meet the general conditions.
There is one important timing rule. The asset must be brought into use for your business in the period you claim the AIA. You cannot buy a second-hand machine in March 2026, store it in a warehouse, and claim the allowance in that tax year. It needs to be available and used for your trade.
What Qualifies as Plant and Machinery for AIA?
HMRC defines plant and machinery broadly. It includes most tangible assets used in your business. Common examples include:
- Commercial vehicles (vans, lorries, tipper trucks)
- Machinery and industrial equipment
- Office furniture and fixtures
- Computer hardware and servers
- Tools and specialist equipment
- Kitchen equipment for hospitality businesses
- Farm machinery and agricultural equipment
If you run a joinery workshop in Digbeth, Birmingham, and buy a second-hand planer thicknesser for £4,200, you can claim the full £4,200 against your profits in the year of purchase. The same applies to a used espresso machine for a café in Stokes Croft, Bristol, or a second-hand van for a plumbing business in Leeds.
What Does NOT Qualify for AIA on Second-Hand Assets?
There are specific exclusions. These apply to both new and second-hand assets, but they catch people out more often with used purchases.
Cars
Passenger cars are excluded from the AIA entirely. This is the most common trap. If you buy a second-hand car for your business, you cannot claim the AIA on it. Instead, you claim capital allowances through the main pool or special rate pool, depending on the car's CO2 emissions. The rates are 18% per year (main pool) or 6% per year (special rate pool) on a reducing balance basis.
Vans and commercial vehicles are different. They qualify for AIA. A used Ford Transit Custom bought for your landscaping business qualifies. A used Audi A4 bought for the same business does not.
Assets Bought Before You Started Trading
If you bought a second-hand asset before your business started trading, you cannot claim AIA on it. The asset must be bought and brought into use for the purposes of your trade. Pre-trading purchases go through a different capital allowances treatment.
Assets Received as Gifts or Inherited
If you acquire a second-hand asset for free, there is no cost to claim AIA against. You cannot claim capital allowances on a nil cost. The same applies if you inherit equipment from a previous business owner or take over assets as part of buying a business. The rules here are more complex and depend on the exact transaction structure.
Assets Used Partly for Non-Business Purposes
If you buy a second-hand asset and use it partly for private purposes, you can only claim AIA on the business-use proportion. A used van used 70% for business and 30% for personal use means you claim AIA on 70% of the cost. This is straightforward but often missed.
Assets Bought from a Connected Person
If you buy a second-hand asset from your spouse, a family member, or a company you control, the AIA claim is restricted. HMRC applies market value rules to prevent abuse. You can only claim the lower of the actual price paid or the asset's market value. This stops artificial transactions designed to generate tax relief.
How to Claim AIA on Second-Hand Assets
You claim the AIA through your annual tax return. For a limited company, this goes on the corporation tax return (CT600). For a sole trader or partnership, it goes on the self-assessment return (SA100 or SA800).
You do not need to submit a separate form. The claim is made by including the qualifying expenditure in the capital allowances computation within your tax return. Your accountant will handle this as part of your year-end accounts preparation.
Keep records of the purchase. You need the invoice, proof of payment, and evidence the asset was brought into use for your business. If HMRC ever queries the claim, you need to show the asset exists and is used in your trade.
Worked Example: Second-Hand Machinery Purchase
Let us run through a realistic example. A Manchester-based precision engineering company buys a second-hand CNC milling machine for £38,500 in December 2025. The company's year-end is 31 March 2026.
The machine is delivered and set up in the workshop by January 2026. It is used exclusively for the business. The company has not used any other AIA expenditure in this financial year.
Result: the full £38,500 qualifies for AIA. The company deducts this from its taxable profits for the year ending 31 March 2026. If the company's corporation tax rate is 19% (small profits rate), the tax saving is £7,315. If the company pays 25% (main rate), the saving is £9,625.
That is a significant cash flow benefit. It effectively reduces the net cost of the machine to £31,185 or £28,875 respectively.
AIA Limit and Associated Companies
If you control multiple companies, the £1,000,000 AIA limit is shared between them. This is the associated companies rule. If you own two limited companies, the AIA limit is split between them. You can agree how to allocate the limit, but the total across all associated companies cannot exceed £1,000,000.
This matters when buying second-hand assets across a group. If one company buys a used machine for £600,000 and another buys used equipment for £500,000, you have exceeded the combined limit. Plan the purchases carefully or accept that some expenditure will go into the main pool at 18% rather than attracting full relief.
Second-Hand Assets and the Special Rate Pool
Some second-hand assets fall into the special rate pool rather than the main pool. These attract AIA at the same rate (100% up to the limit), but any expenditure above the AIA limit goes into the special rate pool at 6% per year rather than 18%.
Assets in the special rate pool include:
- Integral features (electrical systems, air conditioning, lifts, etc.)
- Thermal insulation added to buildings
- Solar panels
- Cars with CO2 emissions over 50g/km (but remember, cars are excluded from AIA anyway)
If you buy a second-hand air conditioning unit for your office, it qualifies for AIA. But if the cost exceeds the AIA limit (unlikely for a single unit, but possible for a full system), the excess goes into the special rate pool.
What About Second-Hand Buildings?
You cannot claim AIA on the purchase of a second-hand building itself. The AIA only applies to plant and machinery, not to land or structures. However, if you buy a second-hand commercial building, you may be able to claim capital allowances on the plant and machinery fixtures within it.
This is a complex area. HMRC requires you to identify the value of qualifying fixtures separately from the building cost. If the seller has already claimed capital allowances on those fixtures, your claim may be restricted. This is where a capital allowances specialist or a formal valuation can help.
Practical Steps for Claiming AIA on Second-Hand Assets
Here is what you need to do to get this right:
- Identify qualifying assets. Check that the second-hand asset is plant and machinery, not a car, building, or excluded item.
- Confirm business use. If there is any private use, calculate the business proportion.
- Check the purchase date. The asset must be bought and brought into use in the same accounting period.
- Check connected party rules. If buying from a relative or connected company, use market value.
- Keep records. Invoice, payment proof, and evidence of use in the business.
- Include in your tax return. Your accountant will add the expenditure to the capital allowances computation.
If you are unsure whether a specific second-hand asset qualifies, speak to your accountant before you buy. A quick check can save you from a missed claim or a later HMRC enquiry.
At Holloway Davies, we are ICAEW qualified accountants who deal with capital allowances claims regularly. We can review your asset purchases and make sure you claim everything you are entitled to.
Common Mistakes with AIA on Second-Hand Assets
Here are the errors we see most often:
- Claiming AIA on a second-hand car. It does not qualify. Use the main pool or special rate pool instead.
- Claiming AIA on assets not yet in use. The asset must be brought into use in the period. Storing it does not count.
- Forgetting the associated companies rule. If you have multiple companies, the £1,000,000 limit is shared.
- Claiming on assets bought before the business started. Pre-trading expenditure has different rules.
- Ignoring private use. Claiming 100% AIA on an asset used 50% privately is incorrect and can trigger penalties.
If you have made any of these errors in a previous return, you can amend it. The time limit is usually 12 months from the filing date. For older errors, you may need to write to HMRC and disclose the mistake voluntarily.
Final Thoughts
The AIA is one of the most valuable capital allowances available to UK businesses. It applies to most second-hand plant and machinery, giving you full tax relief in the year of purchase. The exclusions are specific and manageable.
If your business is buying used equipment, check the AIA rules before you file your return. The tax saving can be substantial, especially for capital-intensive trades like manufacturing, construction, and hospitality.
For tailored advice on your specific situation, contact our team. We can help you structure your purchases and claims to maximise relief.
You can also explore our fundamentals section for more guidance on capital allowances and corporation tax planning.