How to claim R&D Tax Credit on the CT600 Form

‍How to claim an R&D Tax Credit on the CT600 Form

A CT600 is a form that is used by UK companies to file their corporation tax return with HM Revenue and Customs (HMRC). It is used to report your company’s financial information, including income, expenses, and profits, and to calculate the amount of corporation tax that your company owes.

As a form of self-assessment tax, all R&D claims require adjustments to be made to the CT600 in order for the claim to be correctly filed with HMRC. This can be done as part of your original return or through an amendment to the original.

What is a CT600?

A CT600 is the standard HMRC-issue form which is a part of your Company Tax Return; if you are a limited company, you use the CT600 to calculate your corporation tax, including any tax amendments, that you owe – it is a fundamental element of your R&D claim.

Amending your CT600 for R&D claims

Making amendments to reduce your corporation tax (CT) liability is quite straightforward; it only requires you to make changes to your tax return.

Companies claiming R&D tax credits must now also complete a new supplementary CT600L form. Without this information being correctly filled in, your R&D claim will be automatically rejected by HMRC. If your claim is submitted close to the end of your financial year this is particularly important: you may not receive confirmation of the rejection until several months after filing. Failure to include the correct forms before the deadline could result in your claim being disqualified.

Whilst most tax software will assist with the preparation of the CT600L, we’d always recommend seeking advice if you have any doubts. The accurate preparation of an R&D claim with all the supporting documentation requires a detailed knowledge of the processes, and the legislation, in order to ensure the claim is submitted properly.

Merged RDEC scheme and CT600L

When claiming under the merged RDEC scheme, a CT600L must always be completed – the seven steps as part of the RDEC payment mechanism must be completed. They take you through a process from entering the amount being claimed, to applying the tax charge and PAYE/NIC caps; and then determining how the benefit will be received in a hierarchical order from first offsetting corporation tax to eventually claiming a payable credit.

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