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HMRC internal manual

COTAX Manual

Accounting periods: company accounting periods: accounting period records

COTAX gives a two digit number to each AP, in order of the creation of the AP record. The first AP COTAX creates on a company’s record is therefore 01, the next 02, and so on.

Individual AP numbers do not change even if the AP is superseded. COM1160 has more information about superseded APs.

COTAX gives superseding APs new numbers, so the sequence of a company’s AP numbers does not always agree with the date order of the APs.

COTAX gives dormant periods an AP number to complete the database record but does not display it. If a dormant period is later replaced with live APs, the dormant period is deleted from the database and the AP number is lost. This is why a record sometimes has a missing AP number.

COTAX creates and maintains APs in different ways. For more information, see COM1080 for existing cases and COM1100 for new cases.

You sometimes have to intervene to correct APs set up automatically or prevent the future automatic creation of 12 month AP records when the AP end date changes or APs are regularly of less than 12 months.

See COM1080 for full details.