If you run a marketing, digital, or creative agency, you buy equipment. Laptops, monitors, office furniture, servers, software licences, maybe a company car. The question is: how much of that cost can you write off against your corporation tax bill in the same year?
The answer, for most agency founders, is the annual investment allowance (AIA). It lets you claim 100% tax relief on qualifying plant and machinery up to £1 million per year [1]. That means you deduct the full cost from your profits before tax is calculated. No spreading the cost over several years. No complicated calculations.
This guide covers the 2025/26 rules, what qualifies, what doesn't, and how to avoid common mistakes. If you are planning a significant equipment purchase for your agency this year, read this before you sign anything.
What Is the Annual Investment Allowance?
The AIA is a capital allowance that gives you immediate tax relief on qualifying expenditure. You claim it in the accounting period when you buy the item [1]. For most limited company agencies, that means the full cost comes off your taxable profits in the year of purchase.
The current AIA amount is £1 million [1]. This has been in place since 1 January 2019 and was originally intended as a temporary measure. It has been extended several times and remains in force for the 2025/26 tax year [2].
For a typical agency paying corporation tax at 19% or 25%, claiming the full £1 million AIA saves you between £190,000 and £250,000 in tax. That is a significant cash flow benefit.
What Equipment Qualifies for AIA?
The AIA covers most plant and machinery used in your agency. HMRC defines this broadly. It includes:
- Computers, laptops, monitors, and tablets
- Office furniture and fixtures (desks, chairs, shelving, partitions)
- Servers, networking equipment, and data storage
- Telephone systems and video conferencing equipment
- Air conditioning, heating, and ventilation systems
- Company cars (with some restrictions on CO2 emissions)
- Tools and equipment used by your team
- Certain building fixtures (solar panels, lifts, fire alarms)
Software licences are a grey area. If you buy a perpetual licence (a one-off purchase), it typically qualifies. If you pay a monthly subscription, it is revenue expenditure and you deduct it through your profit and loss account, not through capital allowances.
What Does NOT Qualify?
Some items are specifically excluded from the AIA. The main ones for agency founders are:
- Buildings and land, you cannot claim AIA on the cost of buying or constructing a building
- Cars with high CO2 emissions, cars over 50g/km CO2 do not qualify for AIA; they go into the main or special rate pools instead
- Items used partly for business, if you use a laptop 60% for business and 40% personally, you can only claim AIA on the business proportion
- Gifts and items you already owned, you cannot claim AIA on something you owned before starting your business; you use market value instead [3]
- Items bought in the final accounting period before your business closes, no AIA is available in that period [1]
How the £1 Million AIA Limit Works
The £1 million limit applies per accounting period. If your agency has a 12-month accounting period, you get the full £1 million. If your period is shorter, the limit is proportionally reduced.
For example, if your accounting period is 9 months, the AIA will be 9/12 x £1,000,000 = £750,000 [1].
If you spend more than the AIA limit in a period, the excess goes into your main pool (18% writing down allowance) or special rate pool (6% writing down allowance), depending on the asset type. You get tax relief, just spread over several years instead of immediately.
When Is the Equipment 'Bought' for AIA Purposes?
This is where many agency founders trip up. The date you buy the item is not necessarily the date you pay for it or the date it arrives. HMRC has specific rules [1]:
- If you sign a contract and payment is due within less than 4 months, the date you bought it is the date you signed the contract
- If payment is due more than 4 months later, the date you bought it is the date payment is due
- If you buy something under a hire purchase contract, you can claim AIA when you start using the item, for all payments you will make under the contract [1]
This matters for year-end planning. If you sign a contract for £50,000 of equipment on 31 March 2026 (your year-end) and payment is due within 4 months, you can claim the AIA in the 2025/26 period. If you delay signing until 2 April 2026, it falls into the next period.
Full Expensing vs AIA: What Is the Difference?
Since 1 April 2023, the government introduced full expensing for companies. This allows a 100% first-year allowance on qualifying plant and machinery, with no cap [3]. Full expensing is available to limited companies only, not to sole traders or partnerships.
So why use AIA at all? Two reasons:
- Sole traders and partnerships cannot use full expensing. AIA is their main route to immediate relief.
- Special rate assets (long-life assets, integral features, cars over 50g/km CO2) qualify for a 50% first-year allowance under full expensing, but only 6% writing down allowance in the main pool. AIA gives 100% relief on these assets up to the £1 million limit.
For most limited company agencies, full expensing is simpler and more generous than AIA for main pool assets. But AIA remains useful for special rate assets and for sole traders.
Worked Example: A Digital Agency Buying Equipment
Let us run through a realistic scenario. You run a 12-person digital agency in Manchester's Northern Quarter. Your accounting period runs 1 April 2025 to 31 March 2026. Your taxable profit before capital allowances is £400,000.