R&D Claim Notification Form (CNF) – the issues!

Understanding the rules for filing the R&D CNF will help you avoid missing out on this relief for your business.

I’m going to imagine that if you have always made R&D tax credits claims each year, you heard about the notification rules that came into effect in 2023 and thought that they didn’t apply to you as you weren’t making a new claim and had filed in the last 3 years.

Unfortunately, a lot of people have thought that also, and we have seen too many claims being completely lost because of missing or misunderstanding the rules.

So what are the rules for filing an R&D CNF?

There is a 3-year exemption period, which doesn’t follow the accounting periods but instead follows the claim notification period.

The claim notification period is from the 1^st day of the accounting period until 6 months after the end of the accounting period. The 3-year exemption period runs for 3 years back from the end of the claim notification period.

Companies do not have to file a CNF if during the 3-year exemption period they filed a valid R&D tax credit claim subject to two exceptions: –

1. If HMRC rejected the claim by removing it from the company’s tax return this does not count as a claim having been made.
2. If the claim was made for an accounting period beginning before 1 April 2023 by way of an amended return received on or after 1 April 2023, that does not count as an R&D claim having been made.

Let’s look at a worked example

So, assume the accounting period end date is 31 December. The company makes claims every year for R&D, including the following: –

• FY21 Year ended 31 December 2021 – filed by amended return on 22 December 2023
• FY22 Year ended 31 December 2022 – filed by amended return on 20 December 2024
• FY23 ended 31 December 2023 – filed by amended return on 10 December 2025

So what about year ended 31 December 2024, do they need to file a CNF?

Claim notification period ends 6 months after the end of the accounting period, so 30 June 2025. The 3-year exemption period is therefore 1 July 2022 to 30 June 2025.

FY21 therefore was filed within the exemption period, but it falls within exclusion 2 because it was filed by an amended return after 1 April 2023 and was for an accounting period beginning before 1 April 2023.

FY22 was also filed within the exemption period but again falls within exclusion 2 for the same reason.

FY23 was filed after the exemption period ends and so isn’t a valid claim either.

So, unless FY20 is a valid claim, a CNF would be required. If we follow the same pattern, then FY20 would likely have been filed by an amended return in December 2022, which is within the exemption period, and is before 1 April 2023, so it would count for the FY24 CNF to be exempt.

However, it could have easily been instead filed earlier than 1 July 2022.

What about the year ended 31 December 2025 though?

The exemption period is now 1 July 2023 to 30 June 2026.

FY21 and FY22 are both still within exclusion 2 above. FY23 also falls within the exclusion because it relates to a period beginning on 1 January 2023, before 1 April 2023 and was filed in December 2023, after 1 April 2023.

FY24 was likely filed in December 2026 following the trend of the company to file at the end of the 2 year window to make a claim and therefore for FY25 a CNF would be required.

Read more details about the changes.

How to avoid losing out on an R&D claim

It’s therefore very easy for a company to lose out on a claim simply because the CNF was not filed as they didn’t realise it was needed or because by the time they made their accountant aware it was too late.

If you are thinking of making an R&D claim, then do reach out as soon as possible to so that we can review whether you need a CNF and provide you with the deadline therefore to make the notification and decide whether or not you wish to make a claim.

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