Corporation Tax Self Assessment

If your company or organisation is liable for Corporation Tax you'll have to deliver a Company Tax Return to HM Revenue & Customs (HMRC) for each accounting period. This guide explains what you need to deliver with your Company Tax Return form, how to submit your return and what happens once you've done so.

It also explains the new HMRC requirement to complete and deliver your return online from April 2011.

A complete Company Tax Return isn't just your return form CT600 (online or paper version) and the signed declaration at the end of the form.

As part of your Company Tax Return, you normally need to deliver:

  • Company accounts (sometimes known as statutory accounts) - these are the accounts your company must file at Companies House or your organisation must prepare under its constitution. They include director's reports and auditor's reports. However, if your company files abbreviated accounts at Companies House, you must file full accounts as part of your Company Tax Return.
  • Separate computations and/or calculations - for example, if you fill in Boxes 3, 16, 17, 43 to 62, 64, 105 to 121 or 131 you need to attach a document to your return showing how you worked out those figures. Additional documentation you may also need to deliver as part of your return, depending on the particular circumstances of your company or organisation, includes:

Supplementary pages:

  1. Loans to Participators by Close Companies - directors' loans (form CT600A)
  2. Controlled Foreign Companies (form CT600B)
  3. Group and Consortium (form CT600C)
  4. Insurance (form CT600D)
  5. Charities and Community Amateur Sports Clubs (CASCs) (form CT600E)
  6. Tonnage Tax (form CT600F)
  7. Corporate Venturing Scheme (form CT600G)
  8. Cross-Border Royalties (form CT600H)
  9. Supplementary charge in respect of ring fence trades (form CT600I)
  10. Disclosure of tax avoidance schemes (form CT600J)
  11. Any other relevant claims, elections, reports or statements.

Whether you owe 100 or 10,000, the first thing you should do is try to find possible sources to get advice. Please call us or apply online for advice on corporation tax