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HMRC internal manual

Company Taxation Manual

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

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 create 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).

An enquiry may be opened into a later return reflecting the use of a carried forward loss in a later accounting period. Examples include

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

See CTM06300 onwards about the disallowance under CTA10/S673 of trading losses following a change in ownership of a company.