A UK incorporated company must have a senior accounting officer (SAO) for any financial year in which it is a qualifying company, which means that in the previous financial year its turnover was more than £200 million or its balance sheet total was more than £2 billion, either alone or added together with other UK companies in its group. The SAO must take reasonable steps to make sure the company keeps appropriate tax accounting arrangements and must certify to HMRC every year whether it did. Each type of failure carries a fixed £5,000 penalty, charged either on the company or on the SAO personally.

Where do the SAO rules come from and what are they for?

The rules are in Schedule 46 to the Finance Act 2009, and HMRC explains how it applies them in its Senior Accounting Officers Guidance manual (the SAOG pages). They apply by reference to the company’s financial year under the Companies Act 2006, not to tax return periods.

Paragraph 14 of Schedule 46 defines appropriate tax accounting arrangements as accounting arrangements that enable the company’s relevant liabilities to be calculated accurately in all material respects. HMRC says at SAOG14320 that the rules are not about getting returns in on time, so a late return is not in itself evidence that the SAO has failed, although HMRC may ask whether the lateness was caused by weak arrangements.

The relevant liabilities are corporation tax (including amounts charged as if they were corporation tax), VAT, amounts the company accounts for under PAYE, insurance premium tax, Stamp Duty Land Tax, stamp duty reserve tax, petroleum revenue tax, customs duties and excise duties. The SAO role does not replace every director’s wider tax responsibilities.

Which companies have to appoint an SAO?

Under paragraph 15 of Schedule 46, a company is a qualifying company for a financial year if it is incorporated in the UK under the Companies Act 2006 and, for the preceding financial year, it had turnover of more than £200 million, a relevant balance sheet total of more than £2 billion, or both. Where the company is in a group, the figures of the UK companies in that group are aggregated.

Several points catch people out:

  • The test looks back one year: crossing £200 million in the year to 31 December 2025 makes the company qualifying for 2026.
  • Aggregation means a small UK subsidiary of a large UK group is a qualifying company in its own right, even if its own turnover is modest.
  • The test is based on incorporation, so UK tax residence is irrelevant (SAOG11210).
  • Dormant companies and companies in liquidation or administration are not excluded.

Where the position is not obvious, HMRC suggests at SAOG11231 obtaining the previous year’s figures as soon as that year ends, so that the SAO is not identified too late to meet the main duty.

Who can be the SAO?

The SAO is the director or officer who, in the company’s reasonable opinion, has overall responsibility for the company’s financial accounting arrangements (paragraph 16). If the company’s opinion is reasonable, HMRC has no grounds to challenge it.

  • The role cannot be filled by an agent, such as the company’s auditors or external accountants (SAOG12200).
  • In a group, one person can act as SAO for some or all of the UK companies, provided they are a director or officer of a company in the group and have overall responsibility for that company’s financial accounting arrangements. A group can also have several SAOs.
  • The SAO does not have to be based in the UK (SAOG12300).
  • Where a qualifying company is in administration or liquidation, the person meeting the definition could be the administrator or liquidator (SAOG12400).

What does the main duty involve?

The main duty in paragraph 1 is to take reasonable steps to ensure that the company establishes and maintains appropriate tax accounting arrangements. In particular, the SAO must take reasonable steps to monitor the company’s accounting arrangements and to identify any respects in which they are not appropriate.

What is appropriate depends on the size, complexity and nature of the business. HMRC gives the example that for a dormant company the SAO may only need to stay aware of whether it remained dormant throughout the year. The duty extends to work done by other parties, such as an outsourced payroll bureau, where that work affects the calculation of the company’s relevant liabilities. Good accounting records are the starting point, but the SAO is judged on the whole framework.

HMRC says at SAOG18400 that an SAO who takes reasonable steps to spot and fix inappropriate arrangements without delay is unlikely to have failed the main duty.

What must be notified to HMRC and by when?

Under paragraph 3, the company must notify HMRC of the name of each person who was its SAO during a financial year in which it was a qualifying company. There is no set form, but HMRC expects written details of the financial year, the SAO’s name, the part of the year they held the role, contact details and the companies covered (SAOG13200). One notification can cover several group companies if it lists them all.

Only one notification can be made for a financial year, so it cannot be sent until the year has ended. The deadline is the end of the period allowed by the Companies Act 2006 for filing that year’s accounts (see Companies House accounts deadlines): six months after the year end for a public company and nine months for other companies (SAOG13400). If a combined notification covers companies with different filing dates, it must be sent by the earliest of them. There is no need to tell HMRC when a company stops being a qualifying company.

What goes in the annual certificate?

Paragraph 2 requires the SAO to give HMRC a certificate for each financial year in which the company was a qualifying company. The certificate must state either that the company had appropriate tax accounting arrangements throughout the year, or that it did not, in which case it must explain the respects in which the arrangements were not appropriate. These are known as unqualified and qualified certificates.

The deadline is the same as for the notification: the end of the Companies Act period for filing the year’s accounts, unless HMRC allows longer. Extensions should be rare. A specimen unqualified certificate at SAOG15300 refers to paragraph 2 of Schedule 46, names the financial year, and lists each company with its unique taxpayer reference. One certificate may cover several companies.

The certificate must come from the SAO personally. HMRC will not accept a verbal statement, and an emailed certificate needs either the SAO’s identifiable signature or confirmation that the SAO sent it personally (SAOG15600). HMRC may also accept the certificate as the company’s notification if it contains all the notification details.

What are the penalties?

Failure Who is liable Penalty
Company does not notify the SAO’s name on time The company £5,000
SAO fails the main duty The SAO personally £5,000
Certificate not given on time The SAO personally £5,000
Timely certificate with a careless or deliberate inaccuracy The SAO personally £5,000

Each penalty is a fixed £5,000 with no reduction available (SAOG18200). An SAO can be liable both for a main duty failure and for a certificate failure in the same year, but a certificate that is late and also inaccurate attracts only one penalty. In groups, HMRC’s guidance limits repeat penalties of the same type where group companies’ financial years end on the same day.

A reasonable excuse prevents a penalty for late notification, late certification or a main duty failure. There can be no reasonable excuse for a certificate that is carelessly or deliberately inaccurate. An inaccuracy that was innocent when made is treated as careless if the SAO later discovers it and does not take reasonable steps to tell HMRC. Penalties can be appealed and, if necessary, taken to the tribunal.

How does it work in a group? An illustration

Illustration only. A UK public company has a 31 December year end and two UK subsidiaries. For the year to 31 December 2025 the parent’s turnover is £150 million and the subsidiaries’ combined turnover is £80 million, so the aggregated UK figure is £230 million.

  • All three companies are qualifying companies for the year to 31 December 2026, including the subsidiaries.
  • The group decides its chief financial officer, a director of the parent, has overall responsibility for the financial accounting arrangements of all three, and appoints them as SAO for each.
  • The parent is a public company with six months to file, so a combined notification and a single certificate covering all three companies are due by 30 June 2027.

What are the common mistakes?

  • Testing the thresholds against the current year instead of the previous one, and appointing the SAO too late to meet the main duty.
  • Overlooking small UK subsidiaries that qualify only because of group aggregation.
  • Naming an external adviser as SAO, which the rules do not allow.
  • Giving an unqualified certificate when shortcomings were known. The law expects them to be disclosed.
  • Ignoring processes run by third parties, such as payroll providers.

Very large businesses often face the SAO rules alongside the duty to publish a tax strategy and the requirement to notify uncertain tax treatments, which use the same £200 million and £2 billion thresholds. HMRC says at UTT15400 that it would not ordinarily expect an SAO certificate to be qualified just because an uncertain tax treatment has been notified.

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Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 8 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.