How HMRC issues the first two CT600 accounting periods for new companies
Accounting periods for a company with Companies House can have a maximum of 18 months. For example, if you incorporate a company on 1 January 2022 and choose to have a year-end of 31 March, an accounting period cannot be less than 6 months, so your first accounting period with Companies House would be 15months to 31 March 2023.
Whilst Companies House allow this, your accounting periods for corporation tax (CT600 return period) with HMRC are more restrictive only allowing periods up to 12 months.
Therefore, HMRC will automatically issue the first two CT600 periods to align with this 15 months accounting periods with Companies House, where one CT600 return accounting period is for 12 months and the other is for the 3 months to make up the difference.
This can happen in 2 ways:
Long Period then Short Period
Using the existing example, HMRC issued the first period from 1 January 2022 to 31 December 2022 (12 months), then the second period from 1 January 2023 to 31 March 2023 (3 Months).
This is the most common allocation of accounting periods and the expected process as the eventual deadline for filing the first CT600 is 12 months from 31 December 2022, to 31 December 2023. This is aligned with the Companies House deadline for the Statutory Accounts.
Short Period then Long Period
The other scenario is where HMRC issue the first period from 1 January 2022 to 31 March 2022 (3 months), then the second period from 1 April 2022 to 31 March 2023 (12months).
Whilst this scenario is rare, it can cause unexpected issues with HMRC deadlines. This is because the first 3month CT600 return would be due 12 months from 31 March 2022, on 31 March 2023, 9months before the deadline for the first accounts with Companies House
HMRC have issued my first period and it is less than 12 months
Providing you are within the usual statutory deadlines with Companies House, you can call HMRC on 0300 200 3410 to change to a long then short period, thus aligning your deadlines with Companies House.
Again, providing you do this within the 9-month deadline of your first accounts to Companies House, they should reverse your late filing penalties.