Patent Box: reduce Corporation Tax on patented profits

What Patent Box is and why it matters

Patent Box is a Corporation Tax relief that allows UK companies to pay an effective rate of just 10% on profits earned from patented inventions. Compared with the standard 25% main rate, this represents a significant tax saving for companies that commercialise intellectual property.

The relief was introduced by the Finance Act 2012 to encourage companies to develop, manufacture, and exploit patented innovations in the UK. It applies to profits derived from products incorporating a qualifying patent, from licensing patent rights, and from certain other IP income streams.

Who should read this: If your company holds UK or European patents (or is developing inventions that could be patented), Patent Box could substantially reduce your Corporation Tax liability. The relief is available to companies of any size, not just large corporates or pharmaceutical businesses.

Who can claim Patent Box

To elect into Patent Box, your company must meet two fundamental conditions:

1. Ownership or exclusive licence: Your company must own a qualifying IP right or hold an exclusive licence over one. A non-exclusive licence does not qualify.
2. Active development: Your company must have been actively involved in creating the patented invention, or must have performed significant further development of the invention, the patented item, or a product incorporating it.

The active development condition prevents companies from simply acquiring patents and claiming the relief without contributing to the underlying innovation. HMRC expects to see evidence that your company's own employees carried out qualifying development work.

What if you acquired the patent

If your company purchased or licensed a patent rather than developing the invention from scratch, you can still qualify provided you performed significant further development of either the invention itself or a product incorporating it. Routine modifications or cosmetic changes are unlikely to meet this threshold. HMRC looks for genuine technical advancement beyond what was acquired.

Group structures

Where patents are held by one company in a group and exploited by another, group companies can still benefit from Patent Box provided the development condition is met within the group. However, the mechanics of how profits are allocated between group members require careful structuring. Take professional advice if your group holds patents centrally but trades through subsidiaries.

Qualifying IP rights

Not all forms of intellectual property qualify for Patent Box. The relief is deliberately limited to IP rights that involve a rigorous examination and grant process:

• UK patents granted by the Intellectual Property Office (IPO)
• European patents designating the United Kingdom (granted by the EPO)
• Supplementary protection certificates (SPCs) extending patent protection for pharmaceutical and plant protection products
• Plant variety rights granted under the Plant Varieties Act 1997
• Certain regulatory data protection rights in pharmaceuticals

What does not qualify: Trade marks, registered designs, copyright, unregistered design rights, and trade secrets are all excluded. Crucially, pending patent applications do not qualify until the patent is granted, although relief can be backdated to the application date once the grant is confirmed.

Tactical consideration: If your company relies on trade secrets rather than patents, Patent Box cannot apply. For some businesses, the tax saving from Patent Box may justify the cost of filing patent applications, even where trade secret protection might otherwise be preferred. However, patents require public disclosure of your invention, so weigh the commercial trade-offs carefully.

The modified nexus approach

Since July 2016, the proportion of patent profits qualifying for the 10% rate is determined by the modified nexus fraction. This is an OECD-mandated approach designed to ensure that only profits attributable to genuine R&D activity in your company benefit from the reduced rate.

The nexus fraction is calculated as:

Qualifying expenditure x 1.3 (capped at total expenditure) / Total expenditure on the IP

Where:

• Qualifying expenditure = R&D costs incurred by your company directly, plus payments to unrelated subcontractors for R&D
• Total expenditure = All of the above, plus acquisition costs for the IP, plus payments to related parties for R&D

The 1.3 multiplier (known as the "uplift") gives a 30% bonus to your qualifying expenditure, recognising that some outsourced or acquired work supports in-house R&D. However, the result is capped so the fraction cannot exceed 1 (i.e. 100%).

What this means in practice

If your company performed all R&D in-house, your nexus fraction is 1.0 and 100% of patent profits qualify. If you acquired the patent from another company and did no further R&D yourself, your fraction may be close to zero. Most companies fall somewhere between these extremes.

Key implication: Companies that invest heavily in their own R&D benefit most from Patent Box. Outsourcing R&D to connected parties (such as a parent company overseas) reduces the nexus fraction and limits the relief available.

The streaming calculation: how profits are identified

Patent Box does not simply apply a 10% rate to your company's total profits. You must identify the specific profits attributable to qualifying patents through a multi-step calculation known as "streaming".

The calculation follows these broad stages:

1. Identify relevant IP income: Separate your income into five categories (sales of patented items, licence fees, IP disposal proceeds, infringement damages, and other patent-related compensation)
2. Deduct routine return: Subtract a standard 10% return on routine costs (such as premises, equipment, and basic operations) that would arise regardless of patent ownership
3. Deduct marketing return: Subtract a notional return attributable to marketing activities rather than the patent itself
4. Apply the nexus fraction: Multiply the remaining profit by your nexus fraction to determine the proportion qualifying for the 10% rate
5. Calculate the Patent Box deduction: The difference between the standard CT rate and 10%, applied to the qualifying amount, becomes a deduction on your CT600

This calculation is technically demanding. While HMRC provides detailed guidance, most companies use specialist tax advisers or accountants experienced in Patent Box to prepare the computation.

Small claims treatment: For companies with qualifying IP income below a de minimis threshold, a simplified "small claims" calculation is available. This removes the need for the full streaming exercise, making Patent Box accessible to smaller innovative businesses without disproportionate compliance costs.

Interaction with R&D tax relief

Patent Box and R&D tax relief are complementary, not mutually exclusive. A company can claim both reliefs simultaneously, covering different stages of the innovation lifecycle:

• R&D relief reduces your tax bill during the development phase, when you are incurring qualifying R&D expenditure but may not yet have generated profits
• Patent Box reduces your tax bill during the commercialisation phase, once your patented invention is generating income

There is a natural progression: R&D relief supports investment in innovation, and Patent Box rewards the successful exploitation of that innovation. For companies with ongoing R&D programmes that also commercialise patented products, both reliefs can apply to the same accounting period.

Strategic consideration

R&D expenditure that qualifies for R&D tax relief also counts as qualifying expenditure in the nexus fraction. This means that investing in R&D simultaneously delivers three benefits: a direct tax credit or deduction today, a higher nexus fraction for Patent Box purposes, and a potentially patentable invention that unlocks Patent Box in the future.

If your company is already claiming R&D relief, assess whether any resulting innovations could be patented. Even if the patent application process takes 3-5 years, the Patent Box benefit can be backdated to the filing date once the patent is granted.

When to seek professional advice

Patent Box is one of the more technically complex Corporation Tax reliefs. Consider taking specialist advice in these situations:

• First election: The initial setup of Patent Box tracking and the streaming calculation requires careful structuring
• Mixed products: Where your products incorporate both patented and non-patented elements, apportioning income correctly is essential
• Group structures: Allocating patent profits between group companies involves transfer pricing considerations
• Nexus fraction: Optimising your R&D expenditure structure to maximise the nexus fraction requires forward planning
• Patent strategy: Deciding which inventions to patent (versus protecting as trade secrets) should factor in the Patent Box benefit

HMRC's Patent Box guidance runs to several hundred pages. The cost of professional advice is typically modest compared with the potential tax saving, particularly for companies with substantial patent-derived income.