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HMRC internal manual

COTAX Manual

Accounting periods: company accounting periods: new cases

When new cases are set up, COTAX creates APs and periods of dormancy automatically using the information held. The following table sets out what APs are created using the different items of information available.

Information held AP records created
Date of incorporation only. From the date of incorporation for 12 months and then from the day after the end of the above period to the accounting reference date.
Date of incorporation and date business commenced. From the date of commencement of business for 12 months. Any period prior to the date business commenced is marked as dormant.
Date of incorporation, date business commenced and first intended accounting date. From the date of commencement of business to the earlier of the expiry of 12 months or the first intended accounting date. Any period prior to the date business commenced is marked as dormant.

 Automatic creation of APs - Example 1 (Word 36KB)ex1_auto_create_ap.doc and

Automatic creation of APs - Example 2 (Word 36KB)

ex2_auto_create_ap.doc shows how APs are created for new cases.

COTAX accepts amendments to the ‘information held’ column above at any time. It applies the above rules unless any of the following apply.

  • Function MAPD (Maintain AP Dates) has already been used.
  • COTAX has issued a notice to deliver.
  • COTAX has recorded a payment of tax.
  • There is a logged return.
  • A CTSA assessment has been recorded.

In these cases, a screen message advises you that COTAX cannot amend the AP record automatically. You should pass the papers to a Technical Caseworker to update the AP record using function MAPD. See COM1080 for more information.


  • COM1041 for a list of forms relevant to this subject
  • COM1021 for a list of functions to use in particular situations
  • COM1022 for legislation applying to this subject.