Company tax returns

By Tolley in partnership with Jackie Barker of Wells Associates

The following Corporation Tax guidance note by Tolley in partnership with Jackie Barker of Wells Associates provides comprehensive and up to date tax information covering:

  • Company tax returns
  • Corporation tax self-assessment
  • Which form should be used?
  • Accounting periods for corporation tax
  • Company tax calculation
  • Filing deadline
  • Late filing penalties
  • Payment of tax
  • Duty to keep records
  • HMRC guidance

This note offers guidance in respect of the administration of company tax returns. If a company or organisation is subject to corporation tax they will have to complete and file a company tax return for each accounting period. A company or organisation must, in the main, file a return even if they have not made any taxable profits during the accounting period. In this guidance note, ‘company’ includes entities which are not strictly companies but are within the charge to corporation tax, eg unincorporated associations. For information on which entities are within the charge to Corporation tax, see the Charge to corporation tax guidance note.

A company tax return is made up of the company tax return form (form CT600), together with any supplementary pages and other relevant information. The default method of filing is online via the Government gateway using an HMRC online account.

Paper returns are only acceptable if you have a reasonable excuse for being unable to file online or if the company files are in Welsh. In these situations, the company must fill in and post form WT1 to explain why the paper form was used.

For full details of the documents to accompany a tax return, see the Documents to accompany tax return guidance note.

Corporation tax self-assessment

It is the responsibility of the company to assess how much corporation tax is due for each accounting period.

HMRC usually issues a form CT603 Notice to deliver a Corporation tax return shortly after the end of an accounting period.

FA 1998, Sch 18, para 3

If a Notice is not received, HMRC must be notified in writing within 12 months of the end of the period that the company is chargeable. If the company fails to give notice, it is liable to a penalty.

FA 1998, Sch 18, para 2; FA

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