COM50113 - Claims/reliefs: loss and non-trading deficits carry-back: allowing the carry-back (Action Guide)
Source: gov.uk (2025-08-01)


To give effect to a claim for carry-back relief for a CTSA Accounting Period (AP), consider steps 1 - 14 below.

Exceptionally, you can follow this guidance for CT Pay and File APs, using the appropriate assessing functions.

The guide is presented as follows.

Initial action (#initial)

Steps 1 - 3

Making an entry in screen COT120M (#cot120m)

Steps 4 - 14

Initial action

1. Use function MAPS (Maintain AP Signals) to set the ‘inhibit reallocations and repayments (manual)’ signal to ’Y’.

2. Set the clerical interest indicator (CII) see COM95015 (https://www.gov.uk/hmrc-internal-manuals/cotax-manual/com95015) if necessary. See COM50080 (https://www.gov.uk/hmrc-internal-manuals/cotax-manual/com50080) and COM50090 (https://www.gov.uk/hmrc-internal-manuals/cotax-manual/com50090) for more information.

3. Use function RAMA (Record/Amend Assessment) to give effect to the loss carry-back if:
- the self assessment has not been recorded but the return included the loss or non-trading deficit carry-back
- the self assessment has already been recorded and the return does not contain the loss or non-trading deficit carry-back
​Where boxes 170 and 172 (CT600 Version 3) or 6 and 7 (CT600 version 2) have been completed, enter the NT loan profit minus the amount of the carry back and the NT deficit AP end date and NT deficit amount to come to the net figure in box 170 on version 3 (box 6 on version 2). This allows COTAX to calculate the correct repayment interest.

Making an entry in screen COT120M

4. If the profits before the carry-back were charged at the main CT rate with no marginal relief, answer the question ‘MSCR pre and SCR post c/b?’ ‘N’.

5. If the profits before and after the carry-back were charged at the main CT rate with marginal relief, answer the question ‘MSCR pre and SCR post c/b?’ ‘N’.

6. If the profits before the carry-back were charged at the main CT rate with marginal relief and charged at the small profits rate after the carry-back, answer the question ‘MSCR pre and SCR post c/b?’ ‘Y’.

7. If the profits before the carry-back were charged at the small profits rate, answer the question ‘MSCR pre and SCR post c/b?’ ‘N’.

8. If the profits before the carry-back were charged at the small profits rate with marginal relief and at the small profits rate without the relief after the carry-back, answer the question ‘MSCR pre and SCR post c/b? ‘Y’.

9. Change the effective date of payment (EDP) on this screen if required. See COM50080 (https://www.gov.uk/hmrc-internal-manuals/cotax-manual/com50080) for more information.

10. See COM50100 (https://www.gov.uk/hmrc-internal-manuals/cotax-manual/com50100) if you have carried back more than one loss to the AP and you need to change the default order of processing.

11. Complete the assessment.

12. Use function VPPD (View Payment and Posting Details) to check that the ‘LOS’ posting correctly reflects the tax effect of the carry-back and that the EDP is correct.

13. If the ‘LOS’ posting is correct, use function MAPS (Maintain AP Signals) to unset the ‘inhibit reallocations and repayments (manual)’ signal.

If the CII is set, a relief has been displaced, and a repayment is due:
- issue a form CT250(P) to HMRC Payments to notify the interest position. See COM50090 (https://www.gov.uk/hmrc-internal-manuals/cotax-manual/com50090) for more information
- use function DIRR (Direct Repayment) to make the repayment due if the overpayment of tax exceeds the tax effect of the loss and no additional LPI charge is likely following the review of the interest position
COTAX makes any repayment due automatically if CII is not set.

14. If the ‘LOS’ posting is not correct, contact the COTAX Business Help Desk (This content has been withheld because of exemptions in the Freedom of Information Act 2000)