If your performance marketing agency has built custom attribution tooling to solve a genuine technical problem, you might be sitting on a legitimate R&D tax credit claim. Not the "we built a new dashboard" kind. The kind where your developers spent weeks or months trying to figure out how to track conversions across a fragmented customer journey where no off-the-shelf solution worked.

The question is: does building an attribution tool qualify as R&D for tax purposes? The short answer is yes, but only if you can show you resolved technical uncertainty, not just business uncertainty. There is a meaningful difference, and HMRC will look for it.

This article is for agency founders who have built or commissioned custom attribution tooling and want to know whether the costs qualify. We'll walk through the criteria, the common mistakes, and the documentation you need to support a claim. As ICAEW qualified accountants, we've seen claims succeed and fail based on how well the technical story is told.

What HMRC Actually Looks For in an R&D Claim

HMRC's R&D definition has two parts. First, the project must seek an advance in science or technology. Second, it must involve resolving technical uncertainty that a competent professional in the field could not readily resolve.

For a performance marketing agency, the "science or technology" is usually software engineering, data science, or statistical modelling. Building a standard dashboard in Power BI or Tableau does not qualify. Neither does configuring Google Analytics 4 or implementing a third-party attribution platform like Rockerbox or Northbeam.

What does qualify is building novel software to solve a technical problem that has no known solution. For example, if you needed to build a probabilistic attribution model that could handle cross-device tracking without cookies, and you had to develop new algorithms because existing approaches produced unreliable results, that is the kind of project HMRC recognises as R&D.

The Attribution Problem That Can Qualify

Most agencies face the same core problem: the customer journey spans multiple channels, devices, and sessions. A user might see a LinkedIn ad on their phone, search for your client's brand on a desktop, click a retargeting ad on Facebook, and finally convert via a direct visit. Standard last-click attribution underreports the value of upper-funnel channels. Multi-touch attribution is better, but implementing it accurately is technically hard.

If you built a custom solution that:

  • Merges user journeys across devices using deterministic or probabilistic matching
  • Handles data from multiple ad platforms with different attribution windows and deduplication rules
  • Produces statistically valid attribution weights where no standard model existed

...then you may have a qualifying project. The key is that the technical uncertainty existed at the start. You did not know whether it was possible to build a reliable cross-device attribution model given the data available, and a competent data scientist could not have told you the answer in advance.

What Does Not Qualify

HMRC sees a lot of claims that confuse business uncertainty with technical uncertainty. Business uncertainty is "we don't know whether this new attribution model will improve ROAS." Technical uncertainty is "we don't know whether it is technically possible to build a model that can deduplicate conversions across these four ad platforms with less than 5% error margin."

Claims that typically fail include:

  • Configuring off-the-shelf attribution tools. Setting up Rockerbox, Triple Whale, or Northbeam is implementation work, not R&D.
  • Building a standard reporting dashboard. Even if it took months, unless it involved novel data processing, it is unlikely to qualify.
  • Using standard machine learning libraries. Training a model using scikit-learn or TensorFlow is routine unless you had to modify the algorithms themselves to handle your specific data constraints.
  • Projects that failed because of poor project management, not technical difficulty. HMRC will ask: was the uncertainty technical, or was it about resource allocation and timeline?

One of our clients, a 15-person performance agency in Manchester's Northern Quarter, spent six months building a custom attribution model that integrated with Meta, Google, TikTok, and LinkedIn APIs. They thought the whole project was R&D. When we reviewed it, only the work on deduplicating overlapping conversion windows across platforms qualified. The rest was standard API integration work. Their claim was still worthwhile, but it was about 40% of what they originally estimated.

The Qualifying Costs

If your project qualifies, you can claim R&D tax credits for:

  • Staff costs: the salaries, employer NI, and pension contributions of the developers, data scientists, and project managers who worked directly on the qualifying project. You need timesheets or a reasonable estimate of time spent.
  • Software licenses: if you used specific software directly for the R&D, such as specialised statistical modelling tools or cloud computing credits for training models.
  • Subcontractor costs: if you hired external developers or data scientists to work on the qualifying project. The rules differ depending on whether the subcontractor is connected to you.
  • Consumables: costs of materials used up in the R&D process, such as cloud computing resources for running experiments.

For the 2025/26 tax year, the SME R&D scheme gives you an enhanced deduction of 186% of qualifying costs. So if you spent £50,000 on qualifying staff costs, you can deduct £93,000 from your taxable profits. If your agency is profitable, that reduces your corporation tax bill. If you are loss-making, you can surrender the loss for a cash payment worth up to 14.5% of the qualifying costs.

The numbers add up. A £50,000 qualifying project could reduce your tax bill by about £9,500 if you are paying 19% corporation tax, or give you a cash payment of around £7,250 if you are loss-making.

How to Structure Your Claim

HMRC requires a written technical report that explains:

  • The scientific or technological advance you sought
  • The technical uncertainty you faced at the start
  • The work you did to resolve that uncertainty
  • Why that work was not routine

The report must be written by someone who understands the technical work. Usually, that is your lead developer or data scientist. An accountant can help structure the financial side, but the technical narrative must come from the team who did the work.

We recommend keeping a project log as you go. Record the questions your team asked, the approaches they tried and discarded, and the breakthroughs they made. HMRC is more likely to accept a claim that shows genuine iteration and learning than one that presents the project as a straight line from idea to completion.

The Documentation You Need

Beyond the technical report, you need:

  • Timesheets or time estimates for each person who worked on qualifying activities
  • Payroll records showing the costs claimed
  • Invoices for any subcontractors or software licenses
  • Project plans, emails, Slack messages, or meeting notes that show the technical challenges

HMRC does not ask for all of this upfront. But if they open an enquiry, which they do for about 10-15% of R&D claims, you will need to produce it. The better your documentation, the faster the enquiry closes.

Common Pitfalls for Agency Claims

The most common mistake we see is claiming the entire cost of building a product when only a portion qualifies. If your attribution tool took six months to build, but only two of those months involved resolving technical uncertainty, only those two months qualify. The rest is standard development work.

The second mistake is claiming work that was done for a client under a fixed-price contract. If a client paid you to build an attribution model, the R&D belongs to them, not you, unless your contract specifically reserves the IP. You need to check your terms of business before claiming.

The third mistake is claiming without understanding the new rules. Since April 2024, HMRC requires all R&D claims to be made digitally and include detailed breakdowns of costs. Claims must also be endorsed by a named senior officer of the company. The days of filing a one-line R&D claim are gone.

When to Speak to an Accountant

If you think your attribution tooling project might qualify, start the conversation before you submit your company tax return. R&D claims must be made within two years of the end of the accounting period in which the costs were incurred. Miss that window, and the claim is lost.

We recommend getting an initial assessment from an accountant who understands both R&D rules and the agency world. Many general practice accountants will file an R&D claim without properly assessing whether it qualifies, which can lead to HMRC enquiries and penalties if the claim is rejected.

If your agency has built custom attribution tooling in the last two years, contact us. We can review your project against the R&D criteria and tell you whether a claim is worth pursuing. If it is, we will help you structure the technical narrative and prepare the financial breakdown. If it is not, we will tell you that too, and save you the time and risk of a rejected claim.

Final Thoughts

Attribution tooling can qualify for R&D tax credits, but the bar is higher than most agency founders expect. You need genuine technical uncertainty, a clear record of the work done to resolve it, and a claim that separates qualifying activities from routine development.

The payoff is real. A successful claim can return tens of thousands of pounds to your business, cash that can be reinvested into further product development or used to strengthen your balance sheet. But get it wrong, and you risk an HMRC enquiry that costs time, money, and focus you would rather spend on growing your agency.

If you are unsure whether your project qualifies, ask someone who knows the rules. The cost of a professional review is small compared to the value of a well-structured claim or the cost of a failed one.