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HMRC internal manual

Company Taxation Manual

Corporation Tax self-assessment (CTSA): Discovery determination: General

FA98/SCH18/PARA41 (2)

A discovery determination is the counterpart of a discovery assessment.

You make a discovery assessment when a discovery relates to understated profits or overclaimed or overstated relief, that leads to additional tax liability for the company for the period to which the discovery relates - see CTM95030 onwards.

You make a discovery determination when a discovery relates to overstated losses, or overclaimed or overstated relief, and leads (or may lead) to additional tax liability either:

  • for a different period from that to which the discovery relates or
  • for a different company.

Despite the use of the word ‘determination’, a discovery determination under Paragraph 41 (2) is totally different from a ‘revenue determination’ under FA98/SCH18/PARA36 or 37.

You can only make a revenue determination under Paragraphs 36 and 37 when:

  • the company has not delivered a return, or
  • it only partly complies with a notice to deliver a return.

You can only make a discovery determination when the company has already delivered a return.