Box 155 is included within the Income section.
Where a business has made a trading profit during the accounting period, HMRC require the trading profits to be reported in box 155. This is an adjusted trading profit based on the corporation tax computation.
Box 780 Losses of trades carried on wholly or partly in the UK:
Box 780 is included within the 'Losses, deficits and excess amounts' section.
Where a business has made a trading loss on trade carried out wholly or partly in the UK during the accounting period, HMRC require these losses to be reported in box 780.
* Fields as per HMRC CT600 (2021) Version 3 form
Help text for Box 155 provides information about this. Clicking F1 help key while the cursor is in the box will display relevant notes.
HMRC notes for box 155 specify that: This box is for trade profits in Part 3 Corporation Tax Act (CTA) 2009 including any profits arising from trades carried on wholly outside the UK. Enter the total of all the profits in box 155 (including any share of partnership profit and taking into account any Patent Box deductions). Enter the total of all losses in box 780 or 790 (taking into account any Patent Box deductions). Your computations should include a detailed calculation of this figure. Please include a separate calculation of the profit or loss of each trade, showing any adjustments made to the figures in the accounts to arrive at the amount of profit or loss, and any capital allowances or balancing charges included in the calculation of the profit or loss. Where relevant, please also include a calculation of the Patent Box deduction (S357A CTA 2010).
HMRC Data validation messages:
General guidance: In most value fields within CT600, HMRC expect entries of positive values. Customers should not enter a minus sign unless the field specifically allows negative values. In fields for losses, deductions, reliefs, etc. customers are required to provide a positive equivalent of the value. E.g. in field for losses enter value of loss without a minus sign.
Software will display HMRC data validation messages when your entries do not comply with HMRC's validation and the software cannot bypass these HMRC validations and allow incorrect entries.
As there are many queries from customers attempting to enter a minus sign in box 155 to report a negative value, just to clear any doubts, box 155 as it is labelled represents trading 'profits' which cannot be negative. HMRC are specifically asking for profit to be reported here (not a loss).
Disclaimer: We cannot advise on how you should complete your tax returns or how the taxes are calculated. Information provided here is given without any obligations and we will not accept any claims or liabilities for any damages as a result of you relying on the information given here, if in doubt you must consult the HMRC Online Services Helpdesk on 0300 200 3600 or a professional tax advisor.