CTM04150 - Corporation Tax: trading losses: general: relief for losses carried forward: finality of figures

For accounting periods ending on or after 2 July 1999 the loss of the accounting period becomes final in the same way as other figures required by the return (CTM95430). Note that the figure that becomes final with the return is the loss for the accounting period, not the total amount of losses carried forward.

So where a loss has been stated in a return and has become final, the fact that the loss is shown as (or part of) a carry forward amount in computations included with a later return does not give you a second opportunity to enquire into the amount of the loss. An enquiry into the amount of a loss that has become final may be possible following a discovery determination (CTM95500 onwards).

However you can enquire on a later return into the use of a carried forward loss in the later accounting period. Examples include:

• A dispute about whether a trade has continued or whether it has ceased and a new trade commenced.
• The effect of the relevant liabilities restriction (CTM06250) following a company reconstruction.

See CTM06300 onwards about the disallowance under CTA2010/S673 of trading losses following a change in ownership of a company.