Guidance

Corporation Tax: check if you must amend your Company Tax Return

Find out if you need to correct a Company Tax Return for accounting periods ending between 8 March 2017 and 16 November 2017.

Overview

Some Corporation Tax legislation changed in the Finance (No 2) Act 2017. Although the changes received Royal Assent on 16 November 2017 they’re effective from 8 March 2017 for appropriation to trading stock and 1 April for some other areas.

This means some Company Tax Returns that included accounting periods ending between 8 March 2017 and 16 November 2017 may be incorrect. If your return is wrong you need to amend it.

It’s important that you amend your Company Tax Return as soon as possible, as HM Revenue and Customs (HMRC) may open an enquiry into the return if you don’t.

Company Tax Returns that need to be amended

You’ll need to amend your Company Tax return if you filed a return before 16 November 2017 that didn’t take into account the amended legislation for an accounting period ending after:

  • 8 March 2017 and it contains entries that are affected by assets appropriated to trading stock
  • 1 April 2017 and it contains entries that are affected by:
    • loss reform
    • corporate interest restrictions
    • substantial shareholdings exemption
    • offshore property developers
    • restrictions to deductions for employers’ payments into employee benefit schemes

How to amend your Company Tax Return

You can amend your return by either:

  • signing in online
  • writing to your company’s Corporation Tax office (check recent tax forms or letters from HMRC for the Corporation Tax office address or call the helpline)

Get help

You can contact HMRC to get help or more information about:

Contact your company’s HMRC Customer Relationship Manager (CRM) with any other questions.

Contact the Corporation Tax Helpline if you don’t have a CRM.

Published 17 November 2017