Can a company change its accounting year end?
Answered 17 March 2026
Can a Company Change its Accounting Year End?
Yes, a company can change its accounting year end. This involves both company law (notifying Companies House) and tax law (the effect on corporation tax accounting periods).
What the law says
Company law — how to change the accounting reference date
Under the Companies Act 2006, a company may change its accounting year end by giving notice to the registrar (Companies House) specifying a new accounting reference date. The notice can apply to either the current or the previous accounting reference period and all subsequent periods. The notice must state whether the relevant period is to be shortened (ending on the first occasion the new date falls after the beginning of the period) or extended (ending on the second such occasion).
There is an important restriction on extensions: a notice extending the current or previous accounting reference period is not effective if given less than five years after the end of an earlier accounting reference period that was previously extended. However, this five-year restriction does not apply where:
- the company is a subsidiary or parent undertaking of another UK undertaking and the new date coincides with that undertaking's accounting reference date/financial year end;
- the company is in administration; or
- the Secretary of State directs that it should not apply.
Corporation tax — effect on accounting periods
For corporation tax purposes, a company's accounting period ends on the first occurrence of several events, including an accounting date of the company or the ending of 12 months from the beginning of the accounting period (whichever comes first). This means that when a company changes its accounting reference date, the corporation tax accounting period will automatically follow the new accounting date — though if the resulting period would exceed 12 months, it will be split into two accounting periods (the first of 12 months, and a second covering the remainder).
HMRC guidance / practice
HMRC recognises that a company's accounting period may be shorter or longer than 12 months as a result of a change of accounting date (e.g. when a new company joins a group). In such cases, the corporation tax return and any Senior Accounting Officer notification obligations follow the new period.
The period for filing accounts at Companies House — and therefore the deadline for related tax compliance obligations — can only be changed if a formal notification to change the accounting reference date has been made to the Companies House registrar in accordance with section 392 of the Companies Act 2006.
Summary
| Step | Action |
|---|---|
| 1. Company law | File a notice with Companies House under CA 2006 s.392 specifying the new accounting reference date (shortening or extending the period) |
| 2. Restriction on extensions | Cannot extend more than once in any five-year period (unless group alignment, administration, or Secretary of State direction applies) |
| 3. Corporation tax | The CT accounting period follows the new accounting date; if the resulting period exceeds 12 months, it is split automatically into two CT accounting periods |
Citation sources
The Senior Accounting Officer (SAO) must provide a certificate to HMRC not later than the end of the period that is allowed by the Companies Act 2006 for filing the company’s accounts for the financial year at Companies House: For public limited companies this is 6 months after the end of the accounting period. For other companies this is 9 months after the end of the accounting period. In certain circumstances, for example a new company joining a group, the company may have an accounting period
The company must notify HMRC not later than the end of the period that is allowed by the Companies Act 2006 for filing the company’s accounts for the financial year at Companies House: For public limited companies this is 6 months after the end of the accounting period. For other companies this is 9 months after the end of the accounting period. In certain circumstances, for example a new company joining a group, the company may have an accounting period which is shorter or longer than 12 months
Part 15 Accounts and reports Chapter 3 A company's financial year Alteration of accounting reference date 392 1 A company may by notice given to the registrar specify a new accounting reference date having effect in relation to— a the company's current accounting reference period and subsequent periods, or b the company's previous accounting reference period and subsequent periods. A company's “ previous accounting reference period ” means the one immediately preceding its current accounting ref