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AA06 Form UK: Subsidiary Guarantee Statement Guide

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Part ofCompanies House Forms UK

Written by Brad Askew Solicitor (non-practising)
Brad is on the roll of solicitors of England & Wales but does not hold a practising certificate and does not provide legal advice.
Updated June 2026 · England & Wales
If your group structure includes a subsidiary whose accounts are being exempted from audit under a parent company guarantee, there is a specific Companies House form you need to know about: the AA06. It is the official way a parent declares to the registrar that it stands behind the liabilities of its subsidiary for a given financial year. Getting this right matters, because the audit exemption itself depends on the guarantee being properly notified and recorded. In this guide I walk through what the AA06 is for, who signs it, when it has to be filed, and what tends to trip companies up in practice. If you are sitting with the form in front of you and uncertain whether your situation fits, a short call with an adviser can save hours of second-guessing.

What this document is

The AA06 is the Companies House form used by a parent undertaking to give formal notice of a statement of guarantee under section 479A of the Companies Act 2006. In plain terms, it is how a parent company tells the registrar: 'we guarantee the outstanding liabilities of this subsidiary as at the subsidiary's financial year end.' That notification is what allows the subsidiary to take advantage of the audit exemption available to members of a group, provided all the other conditions in sections 479A to 479C are met.

The form is short, but the legal effect is significant. Once the guarantee is given, the parent becomes liable for the subsidiary's outstanding liabilities at the relevant year end until they are satisfied. It is not a rolling guarantee for future debts, it is tied to a specific financial year, and a fresh AA06 is generally needed for each year the exemption is claimed.

How to use this document

  1. Confirm the group qualifies for the exemption. Before touching the form, check that the subsidiary genuinely meets the conditions in section 479A. The parent must be established under the law of a UK country, the subsidiary must be included in consolidated accounts, and members holding a sufficient majority must not have objected. If any condition fails, the AA06 route is not available.
  2. Gather the correct company details. You will need the full registered name and company number of both the subsidiary claiming the exemption and the parent undertaking giving the guarantee. Double-check these against the public register, as mismatches between the form and the filed accounts are a common reason for rejection.
  3. Identify the relevant financial year. The statement of guarantee is made in respect of a specific financial year of the subsidiary. Enter this accurately, because the guarantee attaches to the liabilities outstanding at the end of that year. A guarantee covering the wrong period can undermine the audit exemption entirely.
  4. Have an authorised person sign on behalf of the parent. The AA06 is signed by a director or secretary of the parent undertaking, not the subsidiary. Make sure whoever signs has the authority to bind the parent and understands that the company is accepting legal responsibility for the subsidiary's outstanding liabilities at year end.
  5. File within the statutory deadline. The AA06 needs to reach Companies House in good time, typically alongside the subsidiary's accounts for the year in question, and there are strict timing requirements tied to when members gave their agreement. Late or incorrect filing can mean the exemption falls away and an audit becomes necessary after all.

Common questions

If you're dealing with this kind of situation, speak to an experienced legal adviser who can walk you through it — from £149.

Common questions

Q Who actually signs the AA06 form?
The AA06 is signed on behalf of the parent undertaking, not the subsidiary that benefits from the audit exemption. A director or the company secretary of the parent typically signs. This makes sense when you think about it: the parent is the one giving the guarantee and accepting liability, so the subsidiary's officers cannot sign on its behalf. Make sure the signatory has authority within the parent to commit the company in this way.
Q Do I need to file a new AA06 every year?
Generally yes. The statement of guarantee relates to a specific financial year of the subsidiary and covers the outstanding liabilities at that year end. If the subsidiary wants to rely on the audit exemption for the following year, a fresh notice is usually required. Treating the AA06 as a one-off filing that covers future years is a frequent mistake, and it can cost the group its exemption.
Q What happens if we file the AA06 late?
Missing the filing window can mean the subsidiary loses the audit exemption for that financial year, which then requires a full audit to be carried out. Companies House may also impose penalties in connection with the accounts themselves. If you suspect you are out of time, do not simply file and hope, get a view on whether the exemption is still available for that year or whether you need to pivot.
Q Does giving a guarantee on AA06 make the parent liable for all future debts of the subsidiary?
No. The guarantee is limited in scope: it covers the outstanding liabilities of the subsidiary as at the end of the financial year the notice relates to, until those liabilities are satisfied. It is not an open-ended guarantee of future trading debts. That said, it is still a real legal commitment, and the parent's board should understand what it is signing up to before the form is submitted.
Q Can an overseas parent company give the guarantee?
The rules on which parent undertakings can provide a qualifying guarantee under section 479A have specific requirements about where the parent is established. The position has changed over time, particularly following Brexit, so it is worth checking the current requirements rather than relying on older guidance. If your parent is not incorporated in the UK, confirm eligibility carefully before assuming the AA06 route is open to you.
Q What is the difference between AA06 and the subsidiary's own accounts filing?
They are separate filings that work together. The subsidiary still files accounts with Companies House, but those accounts can be unaudited if the section 479A conditions are met. The AA06 is the parent's notice of guarantee that underpins the exemption. You also need to include the parent's consolidated accounts and certain other documents. Missing any piece of the package can invalidate the exemption.
Q Can the guarantee be withdrawn once it has been given?
Once a statement of guarantee has been given in respect of a financial year, the parent's liability for the outstanding liabilities of the subsidiary at that year end is a real one and continues until those liabilities are satisfied. You cannot simply change your mind and unwind the legal effect of the guarantee for that year. This is why it is so important that the parent's board properly considers the commitment before the form is signed and filed.
If you're dealing with this kind of situation, speak to an experienced legal adviser who can walk you through it — from £149.

Sources

This guide is based on primary UK law and official guidance.

Brad Askew, Solicitor (non-practising)

Written & reviewed by

Brad Askew Solicitor (non-practising)

Brad is on the roll of solicitors of England & Wales but does not hold a practising certificate and does not provide legal advice. LegalDocuments.co.uk is not a law firm and does not provide regulated legal advice.

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Legal disclaimer
This article is for general information only. It is a tool to help you find your way — not legal advice, and not a substitute for speaking to a qualified adviser about your situation.