About the Supplementary Return
The Supplementary Return will list your eligible activities
Your Supplementary Return will automatically pre-populate with details of your approved core and supporting activities.
To complete the return, you can record your actual expenditure alongside each activity.
When is the Supplementary Return due?
You need to file your Supplementary Return within 30 days after the due date of your income tax return.
Extra requirement for Significant Performers
Significant performers must also provide an R&D certificate, signed by an ‘approved certifier’, along with the Supplementary Return.
The R&D certificate provides Inland Revenue with reasonable certainty that you have complied with the requirements set out in your CAM agreement.