The R&D tax adviser market has no fee regulation. Advisers charge what the market bears, and that means the range is wide: from a few hundred pounds for a basic claim by a generalist accountant to tens of thousands for a large-company specialist. The fee model, contingent or fixed, shapes the relationship between adviser and client in ways that go beyond the raw cost. Understanding both models is part of choosing well. Our adviser comparison guide covers the broader selection criteria; this post focuses specifically on the fee structure question.
How Contingent Fees Work in Practice
A contingent fee is typically expressed as a percentage of the tax benefit received. For an RDEC credit under the merged scheme, the tax benefit is the cash credit paid by HMRC. For a profitable company where the RDEC credit reduces the corporation tax payable, the benefit may be calculated as the CT saving rather than a direct cash receipt.
Percentage rates in the market currently range from approximately 10% for large, straightforward claims to 25% for smaller or more complex work. Some advisers apply a sliding scale based on the size of the claim, with higher percentages for smaller claims.
The no-win-no-fee element means the company pays nothing if the claim is rejected or if no relief is received. For a company that has never claimed before and is uncertain whether it qualifies, this removes the risk of paying for work that yields nothing.
How Fixed Fees Work in Practice
A fixed fee is paid regardless of the outcome of the claim. Fixed fees for R&D claims typically reflect the estimated work involved in preparing the technical narrative, the AIF, and the cost schedule. They range from approximately £1,500 for a simple claim on a small qualifying spend to £15,000 or more for a complex multi-project claim requiring detailed technical analysis.
Fixed fees provide cost certainty. The company knows what the adviser costs before the claim is submitted. The fee is owed even if HMRC later disallows part of the claim in a compliance check, though some advisers cap the defence costs within the fixed fee engagement.
Some advisers offer a hybrid: a fixed base fee for claim preparation with a contingent element if the claim exceeds a certain size or if the adviser secures relief above an agreed baseline.
Net Benefit After Fees: the Numbers Matter
The relevant comparison is not the fee in isolation but the net benefit to the company after fees and the quality risk associated with each model.
| Qualifying spend | RDEC credit (20%) | Contingent fee at 15% | Fixed fee (estimated) | Net benefit (contingent) | Net benefit (fixed) |
|---|---|---|---|---|---|
| £100,000 | £20,000 | £3,000 | £2,500 | £17,000 | £17,500 |
| £300,000 | £60,000 | £9,000 | £4,000 | £51,000 | £56,000 |
| £600,000 | £120,000 | £18,000 | £6,000 | £102,000 | £114,000 |
| £1,000,000 | £200,000 | £30,000 | £10,000 | £170,000 | £190,000 |
The table illustrates the growing divergence between fee models as claim size increases. For a £100,000 qualifying spend, the difference is £500. For a £1 million qualifying spend, it is £20,000. Over five years of claiming, the accumulated difference on a mid-sized claim is substantial.
These figures assume equal quality between the two advisers. In practice, the quality of the claim preparation also affects whether HMRC accepts it without challenge, which is the most important variable of all.
How the Fee Model Affects Adviser Behaviour
The fee structure creates different incentives.
Contingent fee advisers are rewarded for maximising the claim. This can be a good thing when it motivates thoroughness in identifying all qualifying cost categories. It becomes a problem if it motivates including borderline or ineligible costs that increase the claim but also increase the enquiry risk. HMRC has flagged systematic overclaiming as a concern in its published guidance on the adviser market.
Fixed fee advisers have an incentive to work efficiently because their fee does not grow with the claim size. A well-run fixed-fee engagement produces a claim that is defensible and complete, not one that is padded. The risk is that a fixed-fee adviser under commercial pressure may underinvest in the technical narrative for the fee they are charging.
Neither model guarantees quality. The best predictor of quality is the adviser's professional standards, track record, professional body membership, and HMRC registration, not the fee model. See our adviser comparison guide for how to assess advisers beyond fee structure.
When a Contingent Fee Makes Sense
A contingent fee is generally appropriate when:
- You are making your first R&D claim and have genuine uncertainty about whether the claim will succeed.
- Your qualifying spend is small enough that the absolute fee difference between contingent and fixed is not material.
- You want the adviser's financial interest aligned with success rather than just completion.
A fixed or capped fee is generally better when:
- You have a large qualifying spend where the contingent fee becomes disproportionate to the work involved.
- The claim is straightforward and well-documented, so the risk element does not justify the premium.
- You are on your second or third year of claiming and the claim process is established.
Check the qualifying expenditure guide to understand what your claim could include, and use our eligibility checker to estimate the claim size before negotiating a fee with any adviser. Knowing your numbers before the conversation gives you the basis for a fair fee discussion. The merged scheme rate comparison may also help you calculate what a given fee level costs as a proportion of the net benefit under current rates.
Frequently Asked Questions
A contingent fee means the adviser charges a percentage of the tax relief received, typically 10% to 25% of the RDEC credit or tax saving. The company pays nothing if the claim is unsuccessful. The percentage applies to each year's claim as long as the arrangement continues.
For smaller claims, the difference between contingent and fixed fee can be marginal in absolute terms. On a £20,000 RDEC credit, a 15% contingent fee is £3,000. A fixed fee for the same work might be £2,000 to £3,500. For large claims, fixed fees become materially better value as the contingent fee scales with the benefit while the work involved does not grow proportionally.
HMRC has raised concerns that some contingent-fee advisers include borderline costs because it increases the claim and the fee. The concern is legitimate but not universal. Well-run contingent-fee advisers apply strict quality controls because overclaims generate enquiries that cost them time and reputation. The fee model alone does not determine quality; the adviser's professional standards do.
Contingent fees typically range from 10% to 25% of the tax benefit received. Lower rates apply to larger claims; higher rates reflect smaller claims or greater complexity. There is no regulatory cap on R&D adviser fees. Some advisers charge a fixed minimum plus a contingent element above a threshold.
Many companies start with a contingent fee to validate the claim, then move to fixed or capped fees once the process is established. For companies with qualifying spend above £500,000, moving to a fixed fee at the second or third renewal typically reduces costs materially. Some specialists offer a cost review specifically at renewal for this reason.
Compare Advisers Before You Commit to a Fee Model
Uplift Tax introductions are to HMRC-registered specialists. We can help you understand the fee options appropriate for your claim size and circumstances. The assessment is free.
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