CTSA: the filing obligation: filing date: definition
You should check the other guidance available on GOV.UK from HMRC as Brexit updates to those pages are being prioritised before manuals.
The filing date for a company tax return is the last day of whichever of the following periods is the last to end:
- twelve months from the end of the period for which the return is made - see example 1 in CTM93050,
- three months from the date when the notice requiring the return is served - see CTM93040 and example 2 in CTM93050 for more detail,
- if the company’s relevant period of account is not longer than 18 months:
- twelve months from the end of that period - see example 3 in CTM93050,
- if the company’s relevant period of account is longer than 18 months:
- 30 months from the beginning of the period of account - see example 4 in CTM93050.
Paragraph 14 (2) defines ‘relevant period of account’. It means in relation to a return for an accounting period, the period of account of the company in which the last day of that accounting period falls. There are examples at CTM93050.
See the On-line Company Tax Manual (COM) ‘Notices and Returns’ business area about the need to notify the computer when the third or fourth bullet applies.